David Wright, Leigh Johnston, Jeff Kershaw, Roger Ordidge, Terence O'Brien, Sandy Shultz

Apparent fibre density (AFD) is postulated to be a sensitive marker of white matter damage and, as it is derived from a continuous fibre orientation distribution, may identify changes along single fibre bundles in regions containing multiple fibre groups. Here, we compared AFD to traditional DTI metrics in an experimental model of traumatic brain injury (TBI). We found that rats given a TBI had widespread regions of reduced AFD when compared to sham-injured rats as well as significant, but less extensive changes in DTI metrics. These results support the use of AFD in assessing disease progression and treatment following TBI.

Lian Li, Michael Chopp, Guangliang Ding, Changsheng Qu, Qingjiang Li, Asim Mahmood, Quan Jiang

Cerebral vascular permeability and hemodynamic alteration in a broad normal appearing brain tissue in response to the transplantation of hMSCs after TBI were longitudinally investigated up to 3-months post-injury. Our data reveal the evidence that a quicker recovery of vascular integrity, as a result of cell transplantation, is associated with a higher level of cerebral perfusion, and acute cell administration after TBI significantly promotes these global therapeutic effects. The findings of the current study indicate that BBB reconstitution plays an essential role in CBF restoration in the injured brain, which in turn, contributes to the improvement of functional outcome. 
 

Samuel Barnes, Brenda Bartnik-Olson, Holshouser Barbara, Stephen Ashwal

Adolescents who sustained a concussion and had persistent symptoms were scanned with DSC-PWI, to assess blood flow, and DTI. Images were compared with controls using automatically defined ROIs by registration to an atlas, and manually drawing ROIs. While both techniques showed similar trends manual ROIs has less variance within groups and therefore greater sensitivity. To detect subtle imaging changes after concussion on an individual basis, manual ROIs, despite being time intensive to define, should still be considered due to their greater sensitivity.

Amy Schranz, Kathryn Manning, Gregory Dekaban, Lisa Fischer, Kevin Blackney, Christy Barreira, Tim Doherty, Douglas Fraser, Arthur Brown, Ravi Menon, Robert Bartha

The effect of concussion on female athletes is underreported in the literature.  This study found reduced glutamine in the prefrontal white matter of female varsity rugby athletes after concussion and in non-concussed athletes after a season of play using proton magnetic resonance spectroscopy (MRS).  Additionally, using diffusion tensor imaging, decreased fractional anisotropy and increased radial diffusivity were found within the spectroscopy voxel in athletes after a season of play.  The observed changes were uncorrelated with clinical test scores suggesting these imaging metrics may be more sensitive to brain injury and could aid in concussion diagnosis and monitoring.

Ferdinand Schweser, Austin Poulsen, Dhaval Shah, Nicola Bertolino, Marilena Preda, Jenni Kyyriäinen, Asla Pitkänen, Robert Zivadinov, David Poulsen

This work investigated if Quantitative Susceptibility Mapping (QSM) can detect thalamic Ca²⁺ influx associated with an alteration of the N-methyl-D-aspartate receptor in a rodent model of mild TBI (mTBI). We found significant concentrations of calcium after repeated mTBI, but not after single mTBI, suggesting that persistent calcium deposits represent a primary pathology of repeated injury.

Yu-Chieh Kao, Chia-Feng Lu, Huai-Lu Chen, Ping-Huei Tsai, Fei-Ting Hsu, Hua-Shan Liu, Gilbert Aaron Lee, Paul Blakeley, Li-Chun Hsieh, Bao-Yu Hsieh, Cheng-Yu Chen

Longitudinal rsfMRI showed the hyper-connectivity in the primary somatosensory cortex and DMN in the acute phase after experimental impact acceleration injury. This is the first demonstration of functional connectivity change with the preserved brain structure after mTBI in rats.

Kevin Koch, Robin Karr, Brad Swearingen, Ashley LaRoche, Casey Anderson, Timothy Meier, Michael McCrea, Andrew Nencka

We present findings of longitudinal quantitative susceptibility mapping measurements on a cohort of contact sport athletes that were imaged longitudinally (24 hour, 8 day, 6 month) following diagnosed sport-related concussions (N=22). A cohort (N=29) of contact sport controls was imaged longitudinally using the same protocol and allowed stability assessment stability of the measurement.  In regions of high stability, changes in susceptibility after injury were assessed in comparison to an atlas constructed from the control data.  Substantial susceptibility variations after injury were found in the deep brain nuclei, which recovered and stabilized in the following two measurement points.  

Barbara Holshouser, Jamie Pivonka-Jones, Joy Nichols, Udo Oyoyo, Karen Tong, Stephen Ashwal

The primary aim of this prospective study was to test the hypothesis that early 3D MR spectroscopic (MRSI) changes in discrete regions of the brain after TBI predict neuropsychologic outcomes 1 year after injury. MRSI was acquired at 3T in 68 pediatric mild to severe TBI subjects and 72 controls. Subacute NAA/Cr and NAA/Cho ratios were significantly reduced in TBI patients in all brain regions. A binary logistic regression analysis using combined subcortical NAA/Cr ratios alone predicted dichotomized neurologic outcome (93%), Full Scale IQ (78%), General Memory (82%) and General Attention (88%).  

Swati Rane, Jalal Andre, Christine MacDonald

This work applied ASL imaging to understand perfusion abnormalities in concussive brain injury. Results show overall reduction in cerebral perfusion, with significant decreases in the frontal and temporal lobes as well as the insula.

Tsang-Wei Tu, Wael Ibrahim, Neekita Jikaria, Dima Hammoud , Joseph Frank

The current study investigated the feasibility of using glucoCEST technique, without delivering exogenous glucose as contrast agent, to measure the endogenous glucose content in brain by optimizing the saturation power and duration. The glucoCEST data were compared to the gold-standard ¹⁴C-2-deoxyglucose autoradiography for testing the sensitivity and specificity in the detection of hypometabolic syndrome in a rat model of diffuse traumatic brain injury (TBI). The glucoCEST showed comparable results to the 2DG-autoradiography showing glucose uptake largely decreased after TBI. Our findings suggest that glucoCEST could be a robust and reliable imaging modality capable of monitoring glucose metabolism non-invasively.

Petr Menshchikov, Tolibjon Akhadov, Olga Bozhko, Natalia Semenova

There is not any information about [GABA] and [GABA]/[GLX] balance in human brain in acute phase of mTBI, but animal studies have shown alterations in concentrations of major inhibitory and excitatory neurotransmitters. [GABA-], [GABA+] and [GLX] were studied in vivo using MEGA-PRES pulse sequence in young patients (mean age - 16±2) with acute phase of mTBI. [GABA-]/[GLX] was significantly increased (p<0.05) in patients and [GABA-]/[tCr] had a trend for increase (p=0.09). This results correlates with animals experiments. [GABA+] didn't show any effects. Thus, [GABA-] MEGA-PRESS is more preferable for accurate [GABA] estimation. 

Chao Chai, Chao Zuo, Linlin Fan, Tianyi Qian, E Mark Haacke, Shuang Xia, Wen Shen

The aim of this study is to explore the changes of regional cerebral venous oxygen saturation (SvO₂) in patients with mild traumatic brain injury (mTBI) using susceptibility mapping (SWIM). SWIM was reconstructed from magnitude and phase data of SWI to measure the susceptibility of cerebral veins in mTBI patients and healthy controls. The results suggested that overall regional cerebral SvO₂ was higher in mTBI patients than controls. The regional cerebral SvO₂ shows that decreased to normal levels along with an increase in elapsed time post trauma and a high-SvO₂ condition is an evidence of neurophysiological deficit.

Ping-Hong Yeh, Chen-Haur Yeh, Gerard Riedy, Wei Liu, Grant Bonavia, John Ollinger

Changes of the fronto-parietal brain metabolites following traumatic brain injury can be reflected in cognitive performance and self-reported psychological function.  These results suggest that MRSI might be sensitive to the disturbance of brain metabolites in chronic military mTBI. 

Chia-Feng Lu, Li-Chun Hsieh, Yu-Chieh Jill Kao, Ho-Fang Huang, Wen-Jin Hsieh, Fei-Ting Hsu, Ping-Huei Tsai, Hua-Shan Liu, Hui-Hsien Lin, Huai-Lu Chen, Cheng-Yu Chen

Disrupted thalamocortical networks and elevated connectivity between thalamic nuclei can reveal the clinical symptoms in mild traumatic brain injury.

Talaignair Venkatraman, Chris Petty, Haichen Wang, John Nouls, Allen Song, Chris Lascola

3D High-Resolution DTI and volumetric analyses in a mouse model of sub-acute injury after TBI with and without neuroprotective therapy.

Arnold Toth, Balint Kornyei, Noemi Kovacs, Andras Buki, Tamas Doczi, Peter Bogner, Attila Schwarcz

This study aims to reveal the relation between traumatic microbleeds (TMBs) on susceptibility weighted imaging and diffuse axonal injury (DAI). Regional TMB and diffusion tensor imaging (DTI) data were collected from 38 traumatic brain injury patients, and 20 control subjects. Analyses included multiple linear regression among TMB parameters, clinical variables and DTI data. Only basal ganglia area TMBs were found to be significantly related to DTI alteration indicating DAI. In general, TMBs might be rather due to microvascular vulnerability than actual DAI, however, specifically basal ganglia area TMBs might be still regarded as markers of DAI.  

Anna Pukropski, Alexander Weber, Michael Jarrett, Christian Kames, Shiroy Dadachanji, David Li, Jack Taunton, Alexander Rauscher

We followed 45 varsity hockey players during one season of play, and scanned all players at the beginning of the season. 11 players received a concussion, and were scanned within 72hrs post-concussion, and then again after 2 weeks and 2 months. Quantitative Susceptibility Maps were created from the multi-echo 3D gradient-echo data, and susceptibility values were measured in deep grey matter (caudate, pallidum, putamen, and thalamus) and frontal and posterior WM in the corpus callosum (genu and splenium). A linear mixed-effect model analysis of the regions of interest revealed no significant changes over time compared to baseline.

Sohae Chung, Els Fieremans, Xiuyuan Wang, Dmitry Novikov, Farng-Yang Foo, Steven Flanagan, Yvonne Lui

Mild traumatic brain injury (MTBI) is a growing public health problem and some patients may suffer from long-term symptoms. This study shows that there are both microstructural changes as well as regional textural changes after MTBI affecting the corpus callosum within 4 weeks of injury. We demonstrate the potential for compartment specific white matter tract integrity (WMTI) metrics such as tortuosity of the extra-axonal space (a marker of misalignment of fibers or demyelination), and Shannon entropy (reflecting complexity or uncertainty) to be useful as early biomarkers of MTBI-related WM injury.

L. Tugan Muftuler, Daniel Olson, Michael McCrea

Mild traumatic brain injury (mTBI) is a prevalent health problem, especially in full-contact sports^{1, 6}. Despite its prevalence, there is still a lack of reliable, unbiased biomarkers of brain injury and recovery following mTBI. Diffusion weighted MRI techniques have gained attention recently in studies of mTBI. Diffusion kurtosis tensor imaging (DKTI) is an extension of the conventional DTI, which estimates non-Gaussianity of bulk diffusion in each voxel. Our studies indicated that DKTI might be potential biomarker to detect subtle changes in brain tissues⁵. Here, we introduce a workflow to detect sites of brain injury in an individual concussed subject.

Asamoah Bosomtwi, Alexandru Korotcov, Angela Pronger, Margalit Haber, Andrew Hoy, Ramon Diaz-Arrastia, Bernard Dardzinski

The long-term dynamic response of microstructural changes in rat brain to the administration of sildenafil after traumatic brain injury (TBI) using non-invasive MRI techniques have been investigated. Our results demonstrate that the treatment of diffuse traumatic brain injury with sildenafil reverses several changes in brain microstructure at 30 days post injury. Diffusion tensor imaging (DTI) data suggests that sildenafil treatment improves white matter reorganization after TBI in rats compared with saline treatment. 

Brenda Bartnik Olson, Katsunori Shijo, Sima Ghavim, Neil Harris, Richard Sutton

Traumatic brain injury initiates a cascade of events including increased oxidative stress that contributes to the period of generalized metabolic depression. Previously, sodium and ethyl pyruvate and glucose supplementation were shown to reduce cell death and improve recovery following experimental TBI. In this study we used ¹³C NMR spectroscopy to determine if sodium pyruvate, ethyl pyruvate or glucose supplementation influences the activity of metabolic pathways associated with the intracellular redox state and oxidative metabolism. Our findings show improvements in astrocyte anaplerotic metabolism following all fuel treatments. Only animals treated with sodium pyruvate showed improved oxidative metabolism in neurons. None of the fuel treatments reduced the amount of glucose metabolized via the pentose phosphate pathway.  The restoration of astrocyte metabolism by these fuels may partially underlie their abilities to improve cerebral glucose utilization and to reduce neuronal loss following experimental TBI.

Wei Liu, Gerard Riedy, Ping-Hong Yeh, Dominic Nathan, Grant Bonavia, John Ollinger

Magnetic susceptibilities of the basal ganglia, as well as the right and left cerebral hemispheres of TBI patients with cerebral microhemorrhage (CMH) were analyzed.  Compared to patients without CMH and controls, patients with CMH demonstrated increased magnetic susceptibility in both the left and right hemispheres but decreased magnetic susceptibility in the basal ganglia. This finding suggests disrupted brain iron hemostatsis due to CMH in the chronic phase of TBI.

Maged Goubran, Sherveen Parivash, Paymon Rezaii, Wei Bian, Brian Boldt, Huy Do, David Douglas, Eugene Wilson, Lex Mitchell, Mansi Parekh, Scott Anderson, Gerald Grant, Michael Zeineh

There is emerging evidence that cumulative sports-related concussions may lead to long-term neurological abnormalities. The extent to which changes are occurring in collegiate athletes is still undetermined, and the progression of these changes is poorly understood. Cross sectional studies with small cohorts have found that concussions maybe be associated with cortical thinning in young football players ^(1,2). We analyze the longitudinal changes occurring in high vs. low contact sports over the course of 3-4 years. 

Riikka Immonen, Amna Yasmin, Asla Pitkänen, Olli Gröhn

In lateral fluid percussion rat model for posttraumatic epilepsy 50% of animals have slowly developed epilepsy 1 year after the head injury.¹ The seizures presumably originate in the perilesional cortex that appears normal in conventional MRI.2 We targeted localized magnetic resonance spectroscopy (MRS) to this cortical area 6 months post-injury, and found elevated Taurine and elevated macromolecule concentration to differentiate the subpopulation (19%) of injured animals with higher susceptibility to seizures in EEG recorded PTZ test. The preliminary immunohistochemical analysis of the underlying complex pathology revealed swollen neurons that may associate with the increase of osmoregulator taurine.

Oscar Bennett, M. Jorge Cardoso, John Duncan, Gavin Winston, Sebastien Ourselin

The visual identification of subtle abnormalities in MR brain images that underlie focal epilepsies is a challenging problem. In this study, we used machine learning techniques to uncover patterns of abnormality that exist within reportedly normal brain images from individuals with epilepsy. Our results demonstrated that abnormalities exist in MR images reported to be normal by a human reader, and that these abnormalities exist in a different spatial pattern to that seen in visually apparent cases. We obtained novel insights into why visual assessment may be ineffective in these visually normal cases and provide suggestions on how to improve this situation.

Dan Benjamini, Michal Komlosh, Peter Basser

Studying the axons’ membrane permeability at different white matter tracts could clarify the role of aquaporins. Diffusion exchange spectroscopy (DEXSY) is an assumption-free approach to measure water exchange, allowing for any number of exchange processes between any number of compartments. It has never been applied in biological MRI owing to its exceptionally long scan time requirements. Here we present a method to reduce the number of required acquisitions, making DEXSY-MRI clinically feasible for the first time. We apply this method on a nerve tissue phantom, and demonstrate that 14 acquisitions are sufficient to determine the exchange spectrum.

Alessandra Caporale, Marco Palombo, Emiliano Macaluso , Michele Guerreri, Marco Bozzali, Silvia Capuani

Motivated by previous results obtained in vitro, we investigated the dependence of the anomalous diffusion γ-parameter on local magnetic susceptibility differences (Δχ) in human brain. We performed diffusion weighted experiments varying diffusion gradient strengths in eight healthy subjects at 3.0T and measured the rate of relaxation (R2*). We found significant strong linear correlations between γ and R2* both in white and gray matter selected regions. Conversely, DTI-parameters did not correlate with R2*. Consequently AD-γ depends on Δχ due to differences in myelin orientation and iron content. This makes AD-imaging even more appealing for clinical neuroimaging investigations.  

Congyu Liao, Kang Wang, Xiaozhi Cao, Dengchang Wu, Qiuping Ding, Hongjian He, Jianhui Zhong

A recently proposed MR fingerprinting (MRF) technique was used to acquire quantitative multi-parametric maps in about 3 minutes for diagnosis of mesial temporal lobe epilepsy in 20 patients. The results could improve the reliability and sensitivity of MRI evaluations in such patients compared with conventional MRI diagnosis methods.

Andrew Weitz, ManKin Choy, Ben Duffy, Jia Liu, Jin Hyung Lee

Optogenetic fMRI studies have traditionally required significant scan averaging to achieve signal-to-noise ratios sufficient for whole-brain functional network mapping. As a result, more scan time is required, and measurements may not directly translate to accompanying behavioral paradigms that employ a single stimulation. Here, we used a SPION-based MRI contrast agent to enable single-scan functional network mapping with CBV during optogenetic stimulation of the thalamic submedial nucleus. Measurement of CBV led to significant activations detected at the site of stimulation and downstream mono- and polysynaptically connected regions. In comparison, single-scan BOLD measurements led to minimal detectable responses to stimulation.

Khin Tha, Ulrich Katscher, Shigeru Yamaguchi, Shunsuke Terasaka, Hiroki Shirato

Madhwesha Rao, Neil Stewart, Paul Griffiths, Graham Norquay, Jim Wild

The feasibility of imaging human brain tissue-perfusion using inhaled hyperpolarized ¹²⁹Xe magnetic resonance imaging is demonstrated. Enhancement of ¹²⁹Xe gas polarization and a custom brain RF coil array have together enabled imaging of hyperpolarized ¹²⁹Xe dissolved in the human brain at 1.5 T with a quality and signal-to-noise hitherto unseen. The images clearly demonstrate the uptake and washout of ¹²⁹Xe in the brain with time and could provide novel insights into cerebral perfusion and blood brain barrier permeability without the use of intravenous contrast.

Erin Englund, Maria Fernandez-Seara, Hyunyeol Lee, Zachary Rodgers, John Detre, Felix Wehrli

An improved interleaved pulse sequence termed “OxBOLD” is presented for calibrated fMRI. OxBOLD measures ASL-based perfusion and BOLD signal changes with whole-brain coverage, in addition to global measures of blood flow and venous oxygen saturation by concatenating background-suppressed 3D-GRASE pCASL, phase contrast, 2D-multi-slice EPI, and dual-echo GRE sequences. The OxBOLD pulse sequence is combined with the Y_v-based calibration model to derive the calibration factor, M, which relates perfusion and BOLD signal changes to the cerebral metabolic rate of oxygen (CMRO₂). M-maps derived from OxBOLD have similar M values averaged over grey matter as compared to the traditional Davis calibration model. 

Salil Soman, Zhe Liu, Ursula Nemec, Samantha Holdsworth, Keith Main, Jerome Yesavage, David Hacknkey, Ansgar Furst, Maheen Adamson, Yi Wang, Pascal Spincemaille, Michael Moseley

Traumatic brain injury often results in brain lesions which are subtle. Current conventional MRI techniques (GRE and SWI) are field strength and echo time dependent, causing lesions to possible be missed. QSM methods can overcome this, but with many artifacts and missed lesions due to masking artifacts. TFI QSM can overcome this issue, as we demonstrate in this study of TBI patients.

Victor Schepkin, Andreas Neubauer, Christian Schuch, Tilo Glaeser, Michael Kievel, Steven Ranner, William Brey, Shannon Helsper, Lothar Schad

The capability of ¹⁷O MRI in a rat head was evaluated at the high magnetic field of 21.1 T (NHMFL, Tallahassee).  The results demonstrated that ¹⁷O MR relaxation times are dependent on the magnetic field strength which correlates with experimental observations for sodium. Well separated MR peaks of ¹⁷O water and 6-¹⁷O glucose provided the time courses of water distribution and glucose consumption in vivo.  3D ¹⁷O MRI is possible with a resolution of 1 mm³ in normal rats.   ¹⁷O MRI is a promising tool for future tumor detection and evaluation of tumor glucose consumption rates.

Tomohiko Horie, Nao Kajihara, Shuhei Shibukawa, Susumu Takano, Toshiki Saitou, Tetsu Niwa, Mitsunori Matsumae, Kagayaki Kuroda, Makoto Obara, Tetsuo Ogino, Isao Muro

We reported a new technique to visualize the irregular motion of cerebrospinal fluid (CSF) by using   dynamic improved motion-sensitized driven-equilibrium steady-state free precession (dynamic iMSDE SSFP). The purpose of this study was to optimize the sequence parameters of dynamic iMSDE SSFP. As a result, the slow and irregular CSF motions were sensitively detected using the following parameters: T2prepTE: 30 ms, dynamic interval: 700 ms, flow VENC: 1 cm/s and the directions of MSG: 3axes. Therefore, optimized dynamic iMSDE SSFP is suggested to contribute to the diagnosis of various diseases in the CSF space.

Christoph Leuze, Subashini Srinivasan, Michael Lin, Brian Hargreaves, Bruce Daniel, Jennifer McNab

In this work we use the Microsoft Hololens for holographic visualization of brain MR imaging data aligned to the real world human body. This provides a way to directly “look inside” the subject’s head instead of treating image and subject as two separate entities.

Valentin Prevost, Olivier Girard, Myriam Cayre, Gopal Varma, Samira Mchinda, Jean-Philippe Ranjeva, Jean Pelletier, Pascale Durbec, David Alsop, Guillaume Duhamel

The ihMT (inhomogeneous Magnetization transfer) signal qualitatively demonstrates sensitivity for myelinated structures. However, image intensity and contrast vary with the saturation parameters, further questioning the specificity of ihM for myelin. This study validated ihMT as a myelin biomarker by demonstrating for various ihMT sequences, linear relationships between ihMT signal and intensity of fluorescence microscopy (a quantitative myelin specific histology technique) collected in plp-GFP mouse brain.

Marsel Mano, Elise Bannier, Lorraine Perronnet, Anatole Lécuyer, Christian Barillot

Neurofeedback (NFB) relies on neurosignals for the estimation of brain activity. There exist a wide variety of NFB applications that use one type of neurosignals like fMRI or electroencephalography (EEG). Recently, the combination of two or more neurosignals has been receiving a lot of attention in the research community, but still very few multi-modal NFB applications exist. This is primarily because of the lack of commercial multi-modal NFB systems and the associated technical difficulties in building them.

Here we are going to describe a bi-modal EEG and fMRI NFB platform that we have build in our lab. Our platform is designed to maximize modularity and parallel processing in order to be able to provide real-time NFB with high level of synchronization and minimal delays. We have successfully used our platform to conduct over 100 uni-modal and bi-modal NFB experiments with more than 30 healthy subjects.

Leonardo Rivera Rivera, Patrick Turski, Oliver Wieben, Scott Reeder, Tilman Schubert , Kevin Johnson

Pulsatility differences in large intracranial arteries and veins have been observed in patients with dementia using 4D flow MRI. How microvascular pulsatility is affected, however, is unclear. Non-invasive methods to monitor capillary pulsatility are still lacking. In this work, we present a method to assess brain parenchyma microvascular pulsatility using T2* signal changes over the cardiac cycle using ferumoxytol enhanced MRI. Significant differences in PI of the cortical gray matter were found when compared to white matter PI values. This method to assess microvascular blood volume pulsatility over the cardiac cycle might serve as a marker to study capillary pulsatility.

Daniel Smith, Hillary Schwarb, Ryan Pohlig, William Oliviero, Bradley Sutton, Tracey Wszalek, Graham Huesman, Curtis Johnson

Mesial temporal sclerosis (MTS), or hippocampal sclerosis, is the most common form of temporal lobe epilepsy and can be effectively treated by surgery if it is able to be reliably detected. In this work we examine whether hippocampal stiffness measured by magnetic resonance elastography (MRE) is sensitive to MTS. In our preliminary sample of five patients with MTS and seven controls, we found the hippocampus to be softer bilaterally in MTS (-13.4% and -15.2% differences for affected and unaffected sides). This preliminary evidence suggests MRE may provide highly sensitive markers that could aid the diagnosis and treatment of MTS.

Nora Weiduschat, Xiangling Mao, Diana Vu, Michelle Blate, Guoxin Kang, Halinder Mangat, Amanda Artis, Yize Zhao, Gudrun Lange, Claire Henchcliffe , Benjamin Natelson, Dikoma Shungu

A prior finding of robust cortical glutathione (GSH) deficits in patients with chronic fatigue syndrome (CFS) and major depressive disorder (MDD) provided a compelling rationale for this pilot study that aimed to assess whether 4 weeks of daily supplements of 1800mg of the GSH synthetic precursor N-acetylcysteine (NAC) would normalize brain GSH in CFS patients, as measured in vivo with J-edited MRS. The study’s main finding was that NAC supplementation significantly increased cortical GSH levels in CFS patients compared to controls, while levels of the antioxidant remained statistically unchanged in controls despite a slight numerical increase.

 

Mohammad Kayvanrad

This work aims at improving the calculation of T1 maps at high magnetic fields from a set of VFA SPGR and IR-SPGR images for direct correction of B1 inhomogeneities using DESPOT1-HIFI. In the present work we (i) call attention to an erroneous assumption regarding the IR-SPGR signal intensity equation in the original DESPOT1-HIFI method and derive an alternative equation, and (ii) propose a reduced-dimensions least-squares fitting method, which turns the complex multi-parameter fitting into a simple one-dimensional search.

Arnold Evia, Aikaterini Kotrotsou, Robert Dawe, Sue Leurgans, Julie Schneider, David Bennett, Konstantinos Arfanakis

In order to establish the role of quantitative susceptibility mapping (QSM) as a diagnostic tool in aging, it is essential to combine QSM with direct assessments of age-related brain pathologies on the same individuals. Using ex-vivo QSM for this purpose may be more advantageous than in-vivo QSM, since ex-vivo QSM assesses the brain in the same condition as histology, and allows imaging of older adults independent of frailty level. However, being able to translate ex-vivo QSM findings to in-vivo is crucial. Therefore, our goal was to investigate the effects of death and fixation on brain QSM data collected ex-vivo.  

Xin Zhang, Linfeng Yan, Yang Yang, Haiyan Nan, Yu Han, Yuchuan Hu, Jin Zhang, Ying Yu, Yingzhi Sun, Qian Sun, Zhicheng Liu, Wen Wang, Guangbin Cui

This study demonstrates the significance of integrating multi-parametric MRI attributes and effective machine learning techniques in preoperative glioma grading. A comprehensive scheme combining tumor attribute extraction, attribute selection and classification model was proposed and tested. The tumor attributes were collected from histogram and texture analysis of multi-parameter MRI maps within the whole tumor. The classification performances of 25 commonly used classifiers combined with 8 kinds of attribute selection strategies in differentiating low grade gliomas from high grade gliomas were investigated. Support vector machine (SVM) combined with SVM-RFE attribute selection method were found to exhibit superior performance to others.

Mizue Suzuki, Yasutaka Fushimi, Tomohisa Okada, Takuya Hinoda, Ryusuke Nakamoto, Yuji Nakamoto, Kaori Togashi

A newly developed " Flexible PET (fxPET)" is a prototype of MR-compatible mobile PET system. We tried to investigate the clinical feasibility of the fxPET with a 1.5T MRI compared with PET/CT for brain imaging. Twenty-one patients ( including 12 patients with known intracranial masses) were enrolled in this study. We compared misregistration between fxPET/MRI and PET/CT, and compared the image quality of fxPET and PET in both qualitative (visual rating) and quantitative (standardized uptake value (SUV)-based analysis ) manner. Consequently, fxPET/MRI showed acceptable misregistration and enough image quality, revealing clinical feasibility comparable to that of PET/CT.  

Graziella Donatelli, Guido Buonicontri, Rosa Pasquariello, Mauro Costagli, Raffaello Canapicchi, Michela Tosetti

In paediatric neuroimaging, young children have often to be sedated in order to obtain diagnostic MRI images. Magnetic Resonance Fingerprinting (MRF) is a potential alternative to sedation in children, as it achieves a fast exam with reduced sensitivity to patient motion. MRF acquisitions can be used to acquire a fully-quantitative anatomical exam in less than five minutes at a standard resolution. We performed a preliminary evaluation of MRF in 15 paediatric patients, acquiring both the standard protocol and MRF at 1.5T.  Detection of brain alterations was possible, if present, in all patients.  Only a few small lesions were unrevealed. MRF could be a promising tool for a fast and diagnostic exam in children, and due to its low sensitivity to motion it has the potential to allow exams without sedation.

Shintaro Ichikawa, Utaroh Motosugi, Yoshie Omiya, Hiroshi Onishi

Hyperintensity in the dentate nucleus (DN) on unenhanced T1-weighted images was associated with previous administration of gadodiamide but not gadoxetic acid. There were no significant differences in DN-to-pons ratio between patients who received five or more administrations of gadoxetic acid and those without gadolinium-based contrast agent administration or chronic liver disease. Hyperintensity in the dentate nucleus on unenhanced T1-weighted images is not associated with up to fifteen previous administrations of gadoxetic acid. Therefore, gadolinium deposition in the brain might be difficult despite a history of repeated gadoxetic acid administration.

Valerie Anderson, Xin Li, Aaron Doud, Ian Tagge, Eric Baker, Joseph Quinn, Jeffrey Kaye, William Rooney

Epithelial cells of the choroid plexus contain the blood-CSF barrier and play a pivotal role in brain water homeostasis. Here, DCE-MRI was used to investigate choroid plexus water exchange in 25 older individuals. A marked non-linearity of blood and tissue R₁ values was observed, indicating that water exchange departs the fast exchange limit at clinical blood contrast agent levels. Using a two-site model that explicitly incorporates water exchange between intra- and extraventricular compartments, a mean rate constant for ventricular water efflux, k_io, of 0.26 ± 0.13 s^-1was obtained. Significant associations of k_io with age and cognitive status were found.

Meher Juttukonda, Manus Donahue, Melissa Gindville, Lori Jordan

Brain tissue oxygen extraction fraction (OEF) and cerebral blood flow (CBF) have been identified as potential imaging biomarkers for triaging adults with sickle cell anemia (SCA) for aggressive blood transfusion therapy for stroke prevention; however, little is known regarding how tissue-level hemodynamics are affected by transfusions. We utilized noninvasive MRI methods to assess OEF and CBF before and after transfusions in adults with SCA. Our results showed that OEF significantly reduces after transfusion and that this reduction parallels increases in blood oxygen content, while CBF is unchanged.

Stephan Kaczmarz, Jens Göttler, Vanessa Griese, Jan Petr, Kim van de Ven, Michael Helle, Hendrick Kooijman, Anne Kluge, Dimitrios Karampinos, Claus Zimmer, Christian Sorg, Christine Preibisch

Internal carotid-artery stenosis (ICAS) causes complex and not yet well understood physiological impairments. We present preliminary data from an ongoing clinical study in ICAS patients and healthy, age-matched participants. The major aims were to evaluate the reliability of a multimodal MRI-protocol and investigate physiological changes. For ICAS patients, regionally impaired vascular-reactivity as well as hypo-perfusion were found. In accordance with literature, we did not find ICAS-induced changes in oxygen extraction on group level. The presented preliminary results thus imply successful application of multimodal MRI methods and are highly promising with respect to gaining a deeper insight into ICAS-related physiological changes.

Sang-Hun Jang, Seung-Man Yu

The objective of this study were to examine the brain metabolite concentration quantification change by in-vivo 1H-MRS analysis in animal hemorrhage model, and we determined the bio-marker that was shown the effect of exercise treatment in hemorrhage disease. No significant difference in the concentration levels of experimental and control group were observed (p=0.839). There was great significance in revealing that (Glu+Gln)/tCr value was increased, and tCho/tCr concentration level was decrease applying exercise treatment methods on hemorrhage animal model. Therefore, the metabolite concentration change of (Glu+Gln)/tCr and tCho/tCr can be used as a powerful bio-marker that represented an exercise treatment in hemorrhage patients.

Mario Lepore, Hongxia Lei

Stroke is a leading cause for disability. Metabolic evolution of transient ischemia attack might shed insights for diagnosis and prognosis. We aimed to ¹H MRS study metabolic evolution of cortex before, during and immediately after 15-min complete global ischemia. Combination of MR angiography (MRA) and ¹H MRS allows execution of vascular occlusion models directly in the magnet as well as proper identification and characterization of complete stroke.

Lena Vaclavu, Zelonna Baldew, Sanna Gevers, Veronica van der Land, Henri Mutsaerts, Karin Fijnvandraat, John Wood, Charles Majoie, Ed vanBavel, Bart Biemond, Aart Nederveen, Pim van Ooij

Hemodynamic parameters such as wall shear stress(WSS) may be adversely affected in Sickle Cell Disease(SCD). Vaso-occlusion is a common complication leading to ischemic organ damage. We investigated how impaired hemodynamics (velocity, WSS, flow and lumen area) relate to ischemic white matter lesions(WMLs). Our aim was to quantify age-related changes in hemodynamics and to investigate their relationship with WMLs. 14 controls and 69 patients underwent 4D-flow MRI. We assessed intracranial velocity, WSS, flow and lumen area in the circle of Willis. We show that 4D-flow parameters are decreased in patients with WMLs, but age is an important factor in this relationship.

Takashi Inoue, Yasutaka Kuzu, Yoshiyuki Kanbara, Shunro Fujiwara, Kuniaki Ogasawara, Teiji Tominaga

Patients with ICH are sometimes treated with surgical evacuation. However, the efficacy of surgery remains unclear for recovery of motor function. We assessed the relationship between motor function outcome and sequential change of FA in patients, to explore whether motor function outcome can be predicted in the early phase. The FA values of the cerebral peduncle on day 3 could predict the motor function outcome on day 90. Patients with severe motor paresis and FA value of greater than 0.7 should be considered for surgical evacuation.

Le He, Shuo Chen, Zhensen Chen, Lixia Yang, Xihai Zhao, Chun Yuan, Huijun Chen

Cerebral blood flow (CBF) reduction below a certain threshold is a main cause leading to cerebral ischemia . Arterial Spin Labeling (ASL) is a noncontrast MRI perfusion technique that can quantify CBF. Although ATA may be problematic for CBF quantification, there are evidences suggest that ATA may be a useful imaging biomarker to represent collateral flow and indicate better outcomes , this study aims to investigate the difference of ATA prevalence between stroke patients with cerebral artery stenosis and healthy volunteers. It was found that the stroke patients have more brain regions with long arterial transit time compared with healthy volunteers using a manual review method to estimate the overall CBF of subject while allowing ATA detection, suggesting ATA could be a potential imaging biomarker.

Xiaoyi Chen, Huilin Zhao, Zechen Zhou, Le He, Rui Li, Chun Yuan, Xihai Zhao

Carotid artery severe stenosis or occlusion will lead to decreases in blood flow and ischemia in downstream arterial segments. It has been shown that ischemia within vessel wall may lead to wall edema which will affect the vascular revascularization after interventional treatment for the severe stenotic or occluded diseases. This study investigated the correlation between extra-cranial carotid artery stenotic diseases and arterial wall edema in ipsilateral petrous internal carotid artery (ICA) using 3D MR vessel wall imaging. We found that proximal ICA severe stenosis was independently associated with wall edema in ispilateral petrous ICA (OR=2.45, 95% CI 1.65-3.63, P<0.001).

Chengcheng Zhu, Xia Tian, Andrew Degnan, Zhongzhao Teng, Jianping Lu, David Saloner, Qi Liu

Intraplaque hemorrhage (IPH) in intracranial arteries is a possible marker of increased stroke risk.  While previous studies focused on stenotic arteries, non-stenotic arteries also cause fatal stroke. We studied 100 patients using high-resolution MRI and found IPH was prevalent (>20%) in both stenotic and non-stenotic basilar arteries, and was a strong predictor of symptoms with an odd ratios of 15.4. IPH has a very high specificity (97.1%) to predict symptoms. Specifically, IPH may be useful in selecting high risk stroke patients with clinically non-significant stenosis, who may benefit from more aggressive treatment.

Jamie Kawadler, Patrick Hales, Fenella Kirkham, Chris Clark

Sickle cell disease (SCD) is associated with chronic anaemia and oxygen desaturation, which elevates cerebral blood flow (CBF) and increases risk of stroke. Cerebral haemodynamics are abnormal and techniques for assessing CBF using a single inflow-time may not be sufficient. This study investigated haemodynamic parameters from a multi-inflow-time acquisition in younger and older children with SCD and healthy controls. CBF was elevated globally in both groups of patients, but in older children, patients had significantly shorter bolus arrival time. This may indicate increasing disparity between patients and controls with age and may be related to longer standing burden of disease.

Tetsuro Sekine, Ryo Takagi, Yasuo Amano, Yasuo Murai, Yoshimitsu Fukushima, Erika Orita, Takahiro Andoh, Yoshio Matsumura, Shin-ichiro Kumita

We performed 4D Flow MRI assessment of the ophthalmic artery (OphA) flow in patients with internal carotid artery stenosis (ICS). Twenty-one consecutive patients with unilateral ICS were recruited. 4D Flow MRI and acetazolamide-stress brain perfusion SPECT were performed. The flow direction on the affected-side OphA was categorized into native flow and non-native flow based on 4D Flow MRI. In the affected-side MCA territory, the ratio of rest cerebral blood flow to normal control (RCBF_MCA) and cerebral vascular reserve (CVR_MCA) were calculated from SPECT dataset. Eleven patients had native OphA flow and the remaining 10 had non-native OphA flow. RCBF_MCA and CVR_MCA were significantly lower in non-native flow group (84.9±18.9% vs. 69.8±7.3%, p<0.05; 36.4±20.6% vs. 17.0±15.0%, p<0.05). Four patients in the non-native flow group and none in the native flow group were confirmed as high-risk (Sensitivity/Specificity, 1.00/0.65). The 6 min-standard 4D Flow MRI assessment of OphA in patients with ICS can predict intracranial hemodynamic impairment.

Hanne Stotesbury, Fenella Kirkham, Chris Clark, Jamie Kawadler

Sickle cell disease (SCD) is associated with stroke¹ and slower processing². Slower processing in the absence of stroke may be related to hypoxic-ischaemic white-matter (WM) injury³. Cognitive assessments and tract-based spatial statistics analyses using diffusion tensor imaging (DTI), were conducted in 84 patients with SCD, stratified by degree of hypoxic-anaemic exposure. Processing speed indices (PSI) were related to WM integrity, and there were differences in PSI and WM integrity as a function of daytime oxygen-desaturation, but not SCI. The results provide links between oxygen desaturation, PSI, and WM integrity, and may indicate amelioration of function by interventions that reduce hypoxic exposure. 

Maria-Eleni Dounavi, Aneurin Kennerley, Solomon Tesfaye, Christopher Martin, Dinesh Selvarajah, Elaine Boland, Iain Wilkinson

This study evaluates cerebral perfusion and cerebrovascular reserve (CVR) in impaired glucose tolerance and patients with type-2 diabetes using QUASAR Arterial Spin Labeling. CVR was evaluated as the change in gray matter CBF in response to a pharmacological stimulus. The developed processing pipeline was based on published QUASAR theory, modified to account for excessive motion and partial volume effects. Results show that baseline CBF is within the expected range. In patients with T2DM and IGT there is a significantly lower value of Cerebrovascular Reserve compared to healthy, normoglycaemic individuals.

Rui Jia, Ningyu An, Xian Xu, Bing Wu

Contrast free arterial spin labeling approach is used to assess the perfusion changes in PCI in the elderly group (>80yrs)compared with normal control elderly group. Lower perfusion level was seen in PCI group, also a long PLD time is more effective in detecting the PCI group in case of slower perfusion rate. The lower level of increment with a long PLD in PCI group also indicates the weakened perfusion ability in the posterior circulation. 

Muhammad Haque, Refaat Gabr, Khader Hasan, Jerome Jeevarajan, Jonathan Izygon, Duyen Nghiem, Clark Sitton, Ponnada Narayana, Sean Savitz

The primary objective of this longitudinal study is to determine the rate of ipsilesional and contralesional lateral ventricular volume (LVv) enlargement in six mild chronic ischemic stroke patients who underwent serial brain MRI at four time points over one year. Infarct volumes, National Institutes of Health Stroke Scale (NIHSS), LVv, gray matter volume (GMv) and white matter volume (WMv) were also measured. Our results show the ipsilesional increase in LVv and the decrease in WMv suggests post-stroke progression of unilateral atrophy.  These changes appear to be independent of the decrease in NIHSS during this same period. This study suggests that MRI can detect pathology that is not reflected by NIHSS.

Xiao Gao, Shengzhang Ji, Yulong Gao, Jinyu Song, Ran Du, Zhizheng Zhuo, Shengli Chen

Based on carotid MR imagings performed on a 3.0T MR scanner with an eight-channel phased-array carotid coil, including 3D TOF, BB-T1WI, BB-T2WI, 3D MP-RAGE, 3D MERGE, We investigated the characteristics of the internal carotid artery angle and common carotid artery bifurcation angle, and compare different forms of carotid bifurcation, analyzed the occurrence of the vulnerable plaques and plaque components, found that bifurcation angles of the internal carotid artery and the common carotid artery have a close relationship with the occurrence of atherosclerosis. Vulnerable plaque with LRNC is more likely to occur at the large angle of the internal carotid artery.

Jilei Zhang, Jingjing Su, Mengxing Wang, Qian Yao, Haifeng Lu, Hui Zhang, Jianqi Li, Jian-Ren Liu, Xiaoxia Du*

In current study, we analyzed resting-state fMRI data for the first time to evaluate the dysfunction of the sensorimotor network in migraineurs without aura by applying regional homogeneity (ReHo), amplitudes of low-frequency fluctuation (ALFF) and degree centrality (DC) analysis methods. The ReHo, DC and ALFF values were decreased in the S1 and PMC indicating the sensorimotor network dysfunction in migraineurs without aura. These changes may result in disruption of discrimination of sensory features of pain, thereby affecting nociception pathways. Non-invasive brain stimulation could be applied to sensorimotor network to modulate headache pain in future therapies.

Mariska Hendriks, Irene Huenges-Wajer, Theo Witkamp, Jeroen Hendrikse, Gabriel Rinkel, Johanne Visser-Meily, Mervyn Vergouwen, Jill De Vis

A significant amount of patients with aneurysmal subarachnoid hemorrhage suffer from cognitive impairment. The exact origin of this cognitive impairment is unclear. Lesions developing in relation to the event have been hypothesized as the mechanism of action. However, literature on this topic is inconclusive. We aimed to scrutinize this by analyzing our cohort of patients. Lesions were found in  60% of patients,  no relation was found with cognitive outcome, This could be due to selection bias as most of the included patients had a good or mild impaired clinical status at admission and demonstrated ‘no cognitive impairment’ at follow-up.  

Kevin Midlash, Yong Jeong, Charles Cantrell, Keigo Kawaji, Greg Christoforidis, Timothy Carroll

Modern stroke research and treatment depend on the ability to accurately characterize and quantify diffusion volume. Current methods for segmentation and quantification of diffusion volumes are largely manual and time intensive. In this paper, we explored and validated a method of automatic segmentation of diffusion volumes. This algorithm was validated against known values from previous studies. We then studied the number of angles required to accurately predict diffusion volumes. We determined accurate volumes can be determined with as few as 3 directional vectors while accurate infarct mapping requires only 7 allowing for reduced scan time.

Cihat Eldeniz, Michael Binkley, Dustin Ragan, Melanie Fields, Kristin Guilliams, Liam Comiskey, Yasheng Chen, Andria Ford, Jin-Moo Lee, Hongyu An

Alterations in cerebral oxygenation may be helpful as an imaging biomarker to predict stroke risk in sickle cell disease (SCD). Such measurement requires the knowledge of susceptibility properties of sickle hemoglobin, HbS. In this study, we aimed at measuring volume susceptibility difference between fully-oxygenated and full-deoxygenated blood, Δχo, of HbS and HbA. The measured Δχo of HbA is consistent with literature reported range, and Δχo of HbS is greater than that of HbA.  However, this difference does not reach statistical significance. 

Arzu Has, Mehmet Pektezel, Mehmet Topcuoglu, Rahsan Gocmen, Bulent Erbil, Nalan Metin Aksu, Ethem Arsava, Kader K. Oguz

Acute elevations in systemic blood pressure can lead to a wide spectrum of central nervous system manifestations, including catastrophic scenarios like intracerebral hemorrhage. We hypothesized that brain swelling occurs in hypertensive crisis patients, assessed by structural MRI. We prospectively collected MRI data from a consecutive series of patients admitted to the emergency department with a diagnosis of hypertensive urgency but no neurologic symptoms. A second MRI was obtained at 3-months follow-up of blood pressure normalization. MRI analysis revealed reductions in cortical and sub-cortical gray matter after normalization of blood pressure.

MungSoo Kang, HyungJoon Cho

 The visualization of post stroke revascularization is of particular importance for the prognosis and therapeutic measures. In this work, using dual contrast R₁-R₂^*-MRAs, visualization of post stroke revascularization on a rat model was performed. R₁-R₂^*-MRAs were used to visualize surface and inner regions of rat brain, respectively. As a result of post stroke revascularization, all MRAs clearly showed thickened vessel structures in ipsilateral hemisphere.

Shanshan Xie, Jingliang Cheng, Yong Zhang, Chengru Song

This study aimed to explore the assessment value of HRMRI and PWI in patients of TIA with unilateral MCA atherosclerotic stenosis. 43 patients with MCA territory symptoms underwent preliminary DWI and MRA to exclude acute cerebral infarction and ascertain unilateral stenosis of MCA M1 segment. Thereafter, all the patients underwent HRMRI and PWI. HRMRI gets 155 positive slices,type ? of plaque 49 (31.6%), IV~?a 41 (26.5%),?b 4 (2.5%), ? 13 (8.4%),?c 48 (31.0%). The soft plaques(type ?~?a and VI) adds up to 54 (34.8%), hard plaques (type III,?b and?c) 101 (65.2%). HRMRI diagnosed four cases of mild stenosis, 11 moderate, 22 severe and 6 occlusion. 42 patients has hemisphere perfusion difference between the affected and normal MCA perfusion districts, with lower rCBF , longer rMTT and TTP (P <0.05) in the affected side.  HRMRI can assess AHA sub-type and stability of atherosclerotic plaque, and stenosis rate of MCA, MTT, TTP can be found changes in early ischemic events, which are sensitive parameters to diagnose TIA.

Shoko Hara, Masaaki Hori, Syo Murata, Ryo Ueda, Misaki Nakazawa, Yoji Tanaka, Taketoshi Maehara, Shigeki Aoki, Tadashi Nariai

We applied Neurite Orientation Dispersion and Density Imaging (NODDI) and neurophysiological batteries to 13 patients with moyamoya disease (10 females, age 16-61 yo). We found that intracellular volume fraction (Vic) and orientation dispersion index (OD) decreased as the stages of vascular lesion progressed, and many neurocognitive tasks correlated with the decrease in Vic and OD among different parts of brain. Interestingly, some tasks were much more correlated with the Vic and OD among posterior part of brain than among frontal part. This finding may suggest the importance of PCA lesions in  neurocognitive disturbance in patients with moyamoya disease.

Brittany Katz, Daniel Albaugh, Chunxiu Yu, Martin MacKinnon, Warren Grill , Yen Yu Ian Shih

Neurovascular coupling is the central principle of functional magnetic resonance imaging (fMRI), and thus critical for the interpretation of most fMRI data. While the strong majority of studies support such a tight coupling between neuronal and vascular activity changes in the cortex, the case may not be so straightforward in brain areas containing different cell types such as the striatum, wherein negative fMRI response has been observed to be positively correlated with1, 2, or uncorrelated with electrophysiologically-measured neuronal activity3, 4. Thus, the rodent striatum is an attractive platform to mechanistically dissect the rules governing neurovascular coupling, providing a novel case in which known coupling rules are violated. Taking this path, we began by asking a simple yet critical question: are neuronal activity increases in striatum causal in striatal negative fMRI response? Our results, employing an optogenetic-fMRI approach coupled with correlative in vivo electrophysiology, reveal that, indeed, selective excitation of striatal neurons drives large-scale local negative fMRI response. However, complementary electrophysiological data also described here suggests that the link between striatal neuronal activity and hemodynamics is more complicated than straightforward negative coupling

Guangxiang Chen, Du Lei, Jiechuan Ren, Xiaoqi Huang, Dong Zhou, Qiyong Gong

The underlying pathophysiological mechanisms of paroxysmal kinesigenic dyskinesia are still not fully understood. The aim of this study was to investigate the patterns of resting-sate functional connectivity of thalamus in patients with paroxysmal kinesigenic dyskinesia. Our novel findings of abnormal resting-sate functional connectivity from thalamus to precentral gyrus and medial frontal gyrus provided direct evidence that the basal ganglia-thalamo-cortical circuit may play an important role in the pathogenesis of paroxysmal kinesigenic dyskinesia.

Adnan Alahmadi, Rebecca Samson, Matteo Pardini, Egidio D'Angelo, Karl Friston, Ahmed Toosy, Claudia Gandini Wheeler-Kingshott

We investigated linear and non-linear BOLD-grip force (GF) relationships in the brain using dominant (DH) and non-dominant hands (NDH). The NDH revealed widespread brain activations compared to DH, irrespective of GF. Looking at the BOLD-GF effects, both hands showed increased activations with increased GF within the contralateral M1 and ipsilateral anterior cerebellum. Non-linear BOLD-GF relationships (up to 4^th order) were found, typically in posterior M1, premotor, sensory, parietal, and cerebellar areas. Finally, the consistent bilateral involvement of the cerebral and cerebellar areas suggests their involvement in error tracking or in synkinetic processes between DH and NDH.

Kyung Eun Jang, Jeehye Seo, Hyejeong Choi, Hyunsil Cha, Eunji Kim, Moojin Yang, Jiung Yang, Huijin Song, Yongmin Chang

Several neuroimaging studies demonstrated that solvent-exposed subjects showed significantly poor performance on the working memory task than did controls [1,2]. However, no investigations have examined how solvent-exposed subjects are influenced by the cognitive load of a working memory task. Therefore, we performed N-back tasks with different cognitive demands using fMRI to investigate the neural basis for possible association between working memory load and memory deficit in the subjects with neurotoxicant solvent exposure. We found a positive correlation between response time of the 1-back task and percent BOLD signal changes in the left inferior parietal cortex, but a positive correlation was not founded of the 2-back task.

DUN DING, XueYing Ma, WangHuan Dun, Peng Li, ZhuoNan Wang, ZHANG MING

To investigate the structure and functional changes in the insulars in uremic RLS patients using a resting-state function magnetic resonance imaging (fMRI )paradigm,We examined cortical thickness,and investigage the abnormal functional connectivity in maintenance dialysis patients. The clinical parameters and RLS severity were correlated analyzed. The characteristics of uremic RLS patients were compared to those of the controls.

Pengmin Qin, Niall W Duncan, David Yen-Ting Chen, Zirui Huang, Chien-Yuan Lin, Christine Wiebking, Chien-Mu Lin, Che-Ming Yang, Ying-Chi Tseng, Georg Northoff, Timothy Lane

We sought to investigate the mechanism involved in temporal variability (TV) changes between two basic behavioral states, namely having the eyes open (EO) or eyes closed (EC). The aim of this study was to use the change between the EC and EO states to identify the potential mechanisms involved in TV modulation.

Wolfgang Grodd, Philip Ehses, Klaus Scheffler, Vinod Kumar

The presented study explores the capability of high resolution functional MRI (fMRI) at 9.4 Tesla to study functional changes in the primary visual cortex and the human thalamus during rest and natural picture viewing. We found increased intrinsic thalamic connectivity during both eyes open (EO) and eyes closed (EC) condition in the viewing task compared to rest.

Min-Hee Lee, Areum Min, Yoon Ho Hwang, Dong Youn Kim, Bong Soo Han, Seung Ku Lee, Chang-Ho Yun, Chol Shin

Obstructive sleep apnea (OSA) is a common and progressive condition that is accompanied by affective, cognitive and autonomic nervous system changes. Recent studies have demonstrated abnormalities in the brains of OSA subjects. However, no study has illustrated alterations in brain structural connectivity caused by OSA. To assess alterations of brain structural connectivity, we constructed a structural brain network from diffusion tensor imaging (DTI) and examined global network properties for control and OSA subjects. OSA subjects showed lower global efficiency, local efficiency and strength. Brain network analysis may improve understanding of global architecture of anatomical connection patterns in OSA.

Jiaming Lu, Xin Zhang, Yun Chen, Jiadong Xia, Zhao Qing, Fei Chen, Huiting Wang, Weibo Chen, Queenie Chan, Yutian Dai, Bing Zhang, Bin Zhu

Premature ejaculation (PE) is considered the alteration in dopaminergic reward system. Functional connectivity density along with network pattern methodology provides an opportunity to assess the functional integrity of brain activity in implicated circuits and it was applied to analysis the inter-group difference in SFCD and LFCD. Network constructing and graph theoretical were used to compare the network property. In conclusion, this study demonstrated the weaken connection inner brain areas and strengthened connection inter brain areas in dopaminergic reward system along with the functional network pattern has changed in the lifelong PE patient for the first time.

Shilpi Modi, Mukesh Kumar, Sanjeev Nara, Subash Khushu

According to the Attentional Control Theory, trait anxiety has a greater adverse effect on processing efficiency (i.e. performance effectiveness/ effort) than on accuracy.  Functional magnetic resonance imaging (fMRI) provides a measure of task-related effort in the form of neural activity elicited during cognitive processing. fMRI was used to assess the neural activation (Blood Oxygen Level Dependent (BOLD) contrast estimates) in a priori regions of interest for a reasoning task. Our results indicate that a compensatory increased neural effort is required by high trait anxious individuals to maintain an equivalent task performance as that of low anxiety individuals.

Takashi Shizukuishi, Osamu Abe, Takahiro Shinozaki, Haruyasu Yamada, Akihiko Wada, Ryutaro Kohashi, Yoshiki Imamura

Objective: We investigated whether autogenic training (AT) altered resting state functional connectivity. Methods: 7 volunteers familiar with AT participated in this study. Rs-fMRI was performed pre and post AT, and 3D-T1WI was acquired. Group analysis was performed to explore the alteration of resting functional connectivity after autogenic training by using CONN functional connectivity toolbox. Results: Greater connectivity between 1. right amygdala and right caudate, 2. precuneus and left pallidum, and 3. right supratemporal gyrus and left pallidum, were demonstrated. Conclusion: AT could have positive effects not only to restore the automatic nervous system but also to alter RS functional connectivity.

Suzanne Witt, Olga Bednarska, Adriane Icenhour, Sigrid Elsenbruch, Johan Söderholm, Maria Engström, Emeran Mayer, Åsa Keita, Susanna Walter

The brain-gut axis is thought to play a key role in the regulation of the gastrointestinal system with overall physical and emotional health.  In diseases, such as irritable bowel syndrome, dysfunction within brain-gut interactions have been proposed to underlie symptoms of chronic abdominal pain.  This study demonstrated that variations in gut mucosal permeability affected both resting-state functional connectivity in the DMN and white matter microstructure properties in healthy adult women.  Variations within brain function and structure were apparent even when variations in gut permeability were small and remained within the normal range, indicating that brain-gut interactions may be quite sensitive.

Suhnyoung Jun, Sanghoon Han, Chang Soo Kim, Seung-Koo Lee

Detrimental effects of air pollutants on cognitive function are gaining considerable concern. The present study compared high-risk and low-risk group, defined based on the level of exposure to air pollutants, using graph theory-based approach and sliding window correlation analysis. Despite the undifferentiated cognitive functions between the groups, our study demonstrated the changes of the large-scale functional networks and dynamic brain activity of the high-risk group. Thus, our findings provide strong evidence of the influence of chronic high-dose exposure to air pollutants on the neural correlates, and offer new ways to understand the functional neural networks and dynamics.

Xin Xu, Song Wang, Qiyong Gong

As a personality trait, hope refers to the motivational tendency for initiating actions and generating routes to achieving goals and plays a protective role in anxiety. Here, we investigated the neural basis of hope in 231 adolescents using resting-state functional magnetic resonance imaging (RS-fMRI). We found that trait hope was negatively associated with the spontaneous activity in the bilateral medial orbitofrontal cortex (mOFC). Further mediation analyses revealed that trait hope mediated the relationship between the mOFC activity and trait anxiety. Taken Together, our findings might provide the initial evidence for the brain-personality mechanisms protecting against anxiety.

Gustavo Pamplona, Frank Scharnowski, Yury Koush, Carlos Salmon

Being able to sustain attention for longer without mind-wandering would improve our performance. The brain correlates underlying both sustained attention and mind-wandering – the so-called sustained attention and default mode networks, respectively – have been well identified. Nevertheless, this knowledge has not yet been translated in advanced brain-based attention training protocols. Here we propose to use a novel brain imaging technique based on real-time fMRI to provide participants with information about ongoing levels of activity. We thus purpose a neurofeedback training of this difference between brain networks, what could lead to a boost in sustained attention ability, which is not reported yet.

Kim Cecil, Thomas Maloney, Mekibib Altaye, Rachel Severs, Christopher Wolfe, Zana Percy, Travis Beckwith, Kimberly Yolton, Grace LeMasters, Patrick Ryan

Traffic-related air pollution (TRAP) is strongly associated with adverse cardiopulmonary health effects. Evidence suggests the developing brain may also be a target organ for particulate matter due to translocation either from the respiratory system or through the olfactory nerve. Using a pediatric cohort, we tested the hypothesis that exposure to TRAP during critical windows of brain development is significantly associated with changes in brain functioning during a language task. Children with high exposure levels were associated with reduced activation within the frontal lobe compared with children at low exposure.

Slim Fellah, Matthew Scoggins, Ping Zou, Lisa Jacola, Ching-Hon Pui, Robert Ogg, Wilburn Reddick

ALL survivors treated with chemotherapy alone remain at elevated risk for neurocognitive impairment. We used fMRI to investigate associations between clinical risk factors, neurocognitive performance and brain activity in survivors of ALL. Ninety-two survivors completed Verbal and Object N-back tasks during fMRI at end of therapy. Measures of working memory were completed as part of a neurocognitive evaluation. Working memory-related brain activation was associated with important clinical risk factors and neurocognitive performance. The pattern of behavioral and imaging responses provides evidence for both compromised and compensatory changes in regional brain function. fMRI may help in selecting patients for remedial intervention.

Eddie Wong, Celia Dong, Russell Chan, Leon Ho, Alex Leong, Condon Lau, Ed Wu

Entrainment is known to alter or synchronize brain rhythm and may enhance task performance. However, whether and how sensory entrainment may modulate the long-range brain functional networks are unknown. We investigated the effects of frequency-dependent visual entrainment on resting state functional connectivity in distinct sensory cortical networks. Our findings provide the first and direct evidence that only low frequency visual entrainment can modulate the long-range non-visual sensory networks. They suggest that the entrained neural oscillation at low frequency can actively contribute to the long-range interactions between primary sensory cortical functional networks that underlie the brainwide connectivity measured by resting-state fMRI.

Ming Zhou, Chuang Yang, Xuan Bu, Haixi Lin, Yan Liang, Lu Lu, Lianqing Zhang, Xinyu Hu, Xiaoqi Huang

In the current study, we used a graph theory-based network measurements named degree centrality (DC) to identify main cortical hubs in the brain network architecture at voxel level affected in ADHD. Then, functional connectivity maps were generated with seeded at altered DC to detect the brain changes at large-scale level. Finally, we found the disconnection within cortico-thalamus and cortico-striatal loops in ADHD patients, which may associated with inattention and cognitive function deficits.

Tong Yang, Xuan Niu

This paper presents an original research to investigate the underlying neural mechanism on acupoint specificity underlying the antiemetic efficacy. Our findings further suggested that acupuncture at different acupoints may exert distinct modulation effects on the brain activity patterns. Notably, we also may provide preliminary evidence for understanding the gut–brain communication.

Pallab Bhattacharyya, Bradley Gill, Javier Pizarro-Berdichevsky, Howard Goldman, Mark Lowe, Stephen Jones

Sacral nerve stimulation (SNS) is an effective treatment for refractory overactive bladder(OAB). For patient-specific and therapeutic efficacy, stimulus at levels below or above the sensory level are sometimes applied on OAB patients. Previous functional brain studies suggested that few forebrain circuits acting primarily on midbrain periacqueductal grey is responsible for facilitating voiding reflex and a sensation of voiding. The neural circuits underlying the action of SNS, and its response to different levels of stimulus is studied by functional MRI (fMRI). Differences in activation patterns resulting from subsensoy, sensory and supresensory stimulation are reported.

Long Zuo, Shuangkun Wang, Hua Gu, Junliang Yuan, Yang Zhou

The problem

The whole-brain functional connectivity strength on long-range and short-range in the AgCC is still unknown.

Methods

A novel voxel-based FCS analysis were performed on the whole-brain resting-state functional images.

Results

Compared with the healthy control subjects, the AgCC groups exhibits statistical differences of FCS on long-range and short-range connecvity respectively.

Conclusions

Anatomical distance affects functional connectivity strength in AgCC individuals.

Ziqi Chen, Mingrui Xia, Weihong Kuang, Zhiyun Jia, Yong He, Qiyong Gong

Previous studies suggested abnormal functional connectivity related to suicide behavior, which however relied on priori selection of seed regions. We applied functional connectivity density (FCD) to investigate the short-range and long-range functional connectivity patterns in major depressive disorder (MDD) patients with suicidal behavior. Relative to healthy controls, MDD patients with suicidal behavior showed reduced short-range FCD in bilateral thalamus, left hippocampus and increased short-range FCD in left precuneus. This study demonstrated altered local connectivity density at voxel level in MDD patients with suicidal behavior and highlighted that the thalamus, hippocampus and precuneus were important brain network hubs for these patients.

Long-Biao Cui, Yi-Bin Xi, Ling-Li Zeng, Guo-Hong Han, Hong Yin

We investigated whether motor system in the brain shows altered functional connectivity and what the anatomical basis behind it is in patients with hepatic myelopathy (HM) after transjugular intrahepatic portosystemic shunt (TIPS), a rare and likely overlooked complication in chronic liver disease patients with portosystemic shunts characterized by severe and mostly irreversible neurologic symptoms. HM patients exhibited hypoconnectivity between the right SMA and right insula, which revealed decreased gray matter volume. The positive correlation was observed between the strength of this connectivity and folic acid level in HM patients, which could discriminate HM from Non-HM with a high level of accuracy.

Hyunkoo Kang, Keuntak Roh

We evaluated the correlation between cerebrovascular reserve (CVR) on acetazolamide-stress single photon emission computed tomography (SPECT) brain scans and collaterals on arterial spin-labeling (ASL) magnetic resonance imaging (MRI) in internal carotid artery (ICA) stenosis.With acetazolamide stress SPECT, the 21/74 (28%) patients showed evidence of decreased CVR. In 7/53 (13%) of the normal CVR group and 10/21 (48%) of the reduced CVR from the SPECT results, ASL showed ATA in ipsilateral to the stenosis. Significant relationship was observed between reduced CVR group and ATA showing group in ICA stenosis patients on ASL brain perfusion (p=0.004).

Yan Bai, Meiyun Wang, Yue Li, Xiaowei He, Xiaoyue Ma, Panli Zuo, Yucheng Li, Xiaolei Song

This study investigated the diagnostic capability of a novel scheme of Length and Offset VARied Saturation (LOVARS) CEST method, for detecting and differentiating intracerebral hemorrhage from ischemic stroke at early stage. With the saturation offsets of 2 ppm and -3.5 ppm, the new LOVARS real image is able to separate ischemic lesion from hemorrhagic lesion by the opposite signal appearances for all patients enrolled. i.e. the former is hypointensity while the latter is hyperintensity. Our results revealed that the LOVARS real signals are significantly higher in hemorrhage than in ischemic stroke, which may serve as an imaging marker.

Kyle Pate, Junjie Wu, Seena Dehkharghani, Fadi Nahab, Jason Allen, Deqiang Qiu

In this paper, 9 patients with chronic cerebrovascular disease underwent a two day MR perfusion study with a Diamox challenge in order to quantify cerebrovascular reserve with a focus on MTT and Tmax parameters. Parametric maps were generated and used to compare regional differences in four perfusion parameters between the left and right hemispheres, MCA and ACA vascular territories, and the cerebellum. This approach demonstrated an unexpected increase in MTT and Tmax augmentation in the anterior circulation over augmentation in the cerebellum.

Jin Gao, Rodolfo Gatto, Richard Magin, Andrew Larson, Weiguo Li

Amyotrophic lateral sclerosis (ALS), a progressive motor neuron disease, is characterized by severe cervical spinal cord damage caused by degeneration of the corticospinal tracts and loss of lower motor neurons. Although MR imaging of spinal cord is challenging, the ubiquity and non-invasive nature of MRI has supported its continued development and a leading role in ALS biomarker discovery. In this study, we investigated the feasibility of exploiting high b-value diffusion MRI to evaluate alterations of the spinal cord in a mouse model of ALS.

Alan Stone, George Harston, Davide Carone, Radim Licenik, James Kennedy, Nicholas Blockley

Streamlined-qBOLD is a baseline brain oxygenation measurement technique that has qualitatively shown promising results for the early identification of the ischaemic penumbra. Here regional definitions of tissue outcome are used to further investigate the application of this technique in acute stroke. Quantitative brain oxygenation parameters are demonstrated to vary between regions with different tissue outcomes.

Shuang Xia, Chao Chai, Qingyuan Yang, Tianyi Qian, E Mark Haacke, Wen Shen

The aim of this study was to explore the correlation between thrombus length, thrombus susceptibility, CBS, DWI-ASPECTS, and admission and discharge NIHSS scores between patients with single-segment and multiple-segment thrombi using susceptibility mapping (SWIM). SWIM, reconstructed from magnitude and phase images acquired by an SWI sequence, was used to measure thrombus susceptibility in patients with acute infarction. A higher susceptibility of thrombus was correlated with lower DWI-ASPECTS and increased NIHSS scores. The patients with multiple-segment thrombi had a larger area of cerebral infarction, more severe symptoms, and worse clinical outcomes.

Pedro Henrique Silva, Ana Paula Camargo, André Paschoal, Octavio Pontes-Neto, Renata Leoni

Asymptomatic unilateral internal carotid stenosis is associated with brain hemodynamic changes and cognitive impairment. However, the effects on Gray Matter (GM) volume, Cerebral Blood Flow (CBF) and Functional Connectivity (FC) are not clear. Therefore, the present study aims to assess changes in brain volume, CBF, resting-state FC and their relation to cognitive decline in a group of patients at presymptomatic stage using MRI. This study confirmed abnormalities in GM volume, CBF, RSBNs and RS-FC in patients, showing that MRI have great potential as biomarker of the disease and may provide additional information to predict cases at risk of brain ischemia.

Shuang Yan, Tianyi Qian, Li Zhang, Josef Pfeuffer, Mingli Li, Bin Peng, Zhengyu Jin

To investigate the perfusion pattern in patients with unilateral middle cerebral artery stenosis, a multi-inversion time pulsed arterial spin labeling technique was used to measure the cerebral blood flow and bolus arrival time (BAT). The preliminary results indicatethat patients with cerebral infarction (CI) had longer BAT than patients with transient ischemic attack (TIA). Assuming CBF valuesare corrected in the areas with BAT longer than 1300ms and combine the corrected CBF with the BAT, we can distinguish TIA and CI cases from their perfusion deficits patterns.

Wang Ting , Xing Xinbo, Wu Bing , Ma Lin , Lou Xin

Carotid endarterectomy (CEA) and carotid artery stenting (CAS) are two commonly used surgical treatment methods for severe internal carotid artery (ICA) stenosis, hence, our objective was to investigate the CBF difference before and in 4-day follow up after CEA and CAS using 3D pCASL technique. As it demonstrated, the CBF values showed no significant (P>0.05) differences in various time points prior to the operations between CAS and CEA, whereas compared to the patients after CEA, the CBF values were stable fluctuated in various time points (P<0.05). This proves that 3D pCASL is useful for quantifying CBF changes after CAS or CEA; moreover, the stable fluctuation CBF may indicate that CAS has a lower hyperperfusion syndrome and death rate compared to CEA in the future.

Noriyuki Fujima, Tomoyuki Okuaki, Takuya Aoike, Suzuko Aoike, Kohsuke Kudo

Diffusion-weighted arterial spin labeling technique was described to depict the tissue water permeability in the brain non-invasively; this information was also described to reflect the degree of blood-brain barrier damage. This study revealed that tissue water permeability can be useful for the evaluation of ischemic lesion more in detail than conventional technique such as T2WI or FLAIR for the determination of severity of ischemia and the prediction how fast the ischemia will progress.

Kyler Hodgson, Ganesh Adluru, Lorie Richards, Jennifer Majersik, Edward DiBella

Improved characterization of brain microstructure is important for image-based methods for diagnosing stroke. We explored the extent to which microstructural maps including Fractional Anisotropy (FA), Generalized Fractional Anisotropy (GFA), and Neurite Orientation Dispersion Density Index (NODDI) detect ipsilateral and contralateral differences in stroke patients as a measure of stroke severity. The difference between hemispheres was correlated with Fugl-Meyer Assessment motor function scores and the results of 16 patient scans reported. Results suggest that the Orientation Dispersion Index (ODI) contains information that could be clinically useful in understanding stroke recovery. 

Jenni Schulz, José Marques, Annemieke ter Telgte, Frank-Erik de Leeuw, Frederick Meijer, David Norris

In this abstract, we demonstrate a clinical application of a MB-PINS-HASTE sequence with TRAPS and compare it to a standard HASTE protocol which is used in daily clinical practice. The modified MB-PINS-HASTE sequence offers the possibility to overcome limitations related to its typically high energy deposition and can accelerate the acquisition by acquiring several slices simultaneously. The reconstructed images show good diagnostic quality for the evaluation of the overall brain and CSF spaces in patients with small vessel disease. MB-PINS HASTE therefore offers the possibility of using ultrafast spin-echo imaging to acquire anatomical T2-weighted images and follow dynamic signal changes.

Masatoshi Takagaki, Yuki Togami, Akira Murasawa, Kazutami Nakao, Manabu Kinoshita

Although outcome of acute cardiogenic cerebral embolism patients improved dramatically due to development of interventional devices, sub-acute cases over the golden period still follow miserable clinical courses requiring to elucidate the pathology of cerebral ischemia. The authors attempted to unveil the correlation of clinical features following cardiogenic cerebral embolism and the locations or sizes of the infarction using voxel-based lesion mapping (VBLM). Our result revealed a correlation between spatial characteristics of infarction and clinical features. Larger ischemic volume at the left hemisphere is correlated with patient’s outcome and cerebral herniation was strongly influenced by ischemic volume after standardization.

Rui He, Olivier Detante, Alexandre Krainik, Assia Jaillard, Emmanuel Barbier, Benjamin Lemasson

Predicting clinical outcome following stroke remains a challenge for magnetic resonance imaging (MRI). In this study, we acquired longitudinally (3 sessions) multiparametric MRI data sets including diffusion-weighted and perfusion-weighted images of 30 patients with chronic ischemic stroke. All of the diffusion and perfusion MRI parameters were analyzed by the classic whole-lesion approach and the parametric response map (PRM), a voxel-based post-processing approach at each time point. The results emphasized the superiority of the PRM over the whole-lesion approach for the prediction of long-term outcome based on early MRI data.

Peter Ludewig, Nadine Gdaniec, Jan Sedlacik, Kannan Krishnan, Christian Gerloff, Tobias Knopp, Tim Magnus

Magnetic particle imaging (MPI) is a new tomographic imaging modality with superior temporal and spatial resolution compared to other imaging techniques, allowing 3D real-time assessment of vasculature and perfusion without X-rays or nephrotoxic contrast agents. For the first time we show that MPI can used for the diagnosis of acute pathologies like ischemic stroke by showing the first MPI stroke images in a murine stroke model. Additionally, we give an outlook how MPI may revolutionize not only stroke imaging but also stroke treatment, as the magnetic fields of the MPI can be used for catheter guidance and targeted drug delivery.

Lisa van der Kleij, Carlo Lucci, Esben Petersen, Mervyn Vergouwen, Gabriel Rinkel, Jeroen Hendrikse, Jill De Vis

Brain injury after aneurysmal subarachnoid hemorrhage (aSAH) has been linked to cerebral hypoperfusion in the acute and subacute disease stage. The areas most prone to hypoperfusion are the borderzone regions. In this study we obtained cerebral blood flow measurements in the subacute stage after aSAH, and longitudinal volumetric data. We found a moderate correlation between the ratio of borderzone/whole-brain perfusion and percentage brain volume loss. Thereby, perfusion in the watershed areas in the subacute stage could identify patients at a higher risk for future brain parenchymal volume loss. Consequently, increasing perfusion in these regions could be a future therapeutic target. 

Ya-Fang Chen, Sung-Chun Tang, Yen-Shu Kuo, Wen-Chau Wu

Internal carotid artery stenosis (ICAS) has been identified as a risk factor of ischemic stroke, with altered flow velocity and narrowed lumen commonly assessed by ultrasonography and angiography. However, hemodynamic change/compensation in microvasculature cannot be ruled out before symptoms. In this study, we investigated cerebral perfusion changes in asymptomatic ICAS by simultaneously assessing cerebral blood flow (CBF), arterial transit time (ATT), and flow territory, derived from arterial spin-labeling (ASL) MRI. Our data suggest that ATT and flow territory may be better predictors of high-grade unilateral ICA stenosis (≥70 %) than CBF in asymptomatic patients.

Yihao Xia, Yaqiong Chai, Adam Bush, Natasha Lepore, Thomas Coates, John Wood

Sickle cell disease (SCD) is a genetic blood disorder with a high prevalence of cerebral vasculopathy and stroke. Arterial Transit Time (ATT) refers to the time it takes blood to flow from the labeling plane, to the vascular imaging compartment and reflects cerebrovascular impairment in SCD. We used pseudo continuous arterial spin labeling to measure ATT with flow encoding arterial spin tagging technique in patients with SCD and ethnicity matched, healthy controls. Our findings demonstrated sensitivity of ATT to vasculopathy. 

Ulf Jensen-Kondering, Ruwen Böhm, Liang Shu, Olav Jansen, Ulrich Katscher

Electric properties tomography (EPT) is a new contrast in MRI which delivers information on tissue electrical conductivity. Up to now, it has been mostly used for tumor mapping. Ischemic cerebral stroke is another promising application. Seven male Wistar rats were used in this study. Five culled animals from another stroke study, three of which were subjected to MCAO and two live animals which were also subjected to MCAO were examined. Healthy cortical grey matter, white matter and  cerebrospinal fluid could be well differentiated Conductivity was altered within the infarct. EPT is feasible in a rodent model of stroke.

Wenjing Lan, Shuang Xu, Yang Liu, Kaining Shi, Lizhi Xie

Diffusion tensor imaging (DTI) has been the most commonly used modality among diffusion MRI methods in the studies of ageing and development in the current study, we investigated diffusional modifications arising from brain small vessel disease, as compared with age and educational level matched healthy controls.  Diffusion kurtosis imaging (DKI) was applied throughout the study, which is a recent novel extension of DTI to provide additional metrics quantifying non-Gaussianity of water diffusion in brain tissues.

Hongfu Sun, Derek Emery, Kenneth Butcher, Alan Wilman

To follow the time evolution of intracranial hemorrhage (ICH) using quantitative susceptibility mapping (QSM) and compare to CT. Twenty ICH patients were followed using a clinical MRI protocol typically performed on day 2, 7 and 30. The ICH areas and mean values were compared between the CT and QSM on 18 patients (average 1.7 days apart). Time evolution of ICH was also investigated by QSM. In conclusion, QSM can be used to measure the size of ICH and track susceptibility evolution of the blood degradation products, providing a means to track iron evolution.

Takamasa Namba, Kuniaki Ogasawara, Hideaki Nishimoto, Daiya Ishigaki, Yoshichika Yoshioka, Toshiyuki Murakami, Makoto Sasaki, Masakazu Kobayashi, Kenji Yoshida, Ikuko Uwano, Shunrou Fujiwara, Kazunori Terasaki, Akira Ogawa

Deep cerebral white matter (CWM) like the centrum semiovale is vulnerable to ischemic injury. Brain temperature (BT) was associated with cerebral hemodynamic abnormalities in patients with chronic ischemia. We investigated whether the BT distribution map by multi-voxel ¹H-MRS were associated with the cerebral hemodynamic abnormalities assessed by positron emission tomography (PET) in the CWM region of patients with unilateral chronic major cerebral artery steno-occlusive disease. The BT map quantitatively and qualitatively correlated with PET images, especially oxygen extraction fraction. This may help to identify the patients at high risk for the stroke recurrence.  

Carlo Lucci, Lisa van der Kleij, Mervyn Vergouwen, Gabriël Rinkel, Jeroen Hendrikse, Jill De Vis

Aneurysmal Subarachnoid Hemorrhage (aSAH) accounts for only 5% of all strokes, but it is a disabling disease because of the cognitive deficits that occur in many survivors. We hypothesize these deficits to be caused by an accelerated brain atrophy process that develops after the event. To investigate this hypothesis, we evaluated brain volume changes in aSAH patients over time.

Jonghyun Bae, Jin Zhang, Orlando Aristizabal, Willis Chen, Youssef Zaim Wadghiri, Yulin Ge, Sungheon Gene Kim

The purpose of this study is to investigate the feasibility of reducing the scan time while maintaining the sensitivity to BBB permeability changes. We propose a new model, extended Patlak model (EPL), where plasma flow is added to the Patlak model. The numerical simulation and in vivo mouse data in this study suggest that the proposed EPL model can be used to measure BBB permeability change with DCE-MRI scan time of 10 min or less.

Jelena Lazovic, Whitney Pope, Massoud Akhtari

In the current study we tested if accumulation of non-radioactive 2-deoxy-D-glucose (2DG)-conjugated magnetonanoparticles (2DG-MNP) can be used as a measure of metabolic activity in glioblastoma. To quantify 2DG-MNP uptake across brain ΔR₂ maps are proposed. The difference in R₂ relaxation rates prior to and at different times following 2DG- or unlabeled (plain) MNP administration represents ΔR₂. Significant changes in ΔR₂ between brain and glioblastoma, reflecting increased metabolic rate of glioblastoma were found for glucose labeled MNP and not for plain-MNP.  Our results suggest that 2DG-MNP have potential to be utilized in metabolic imaging as non-radioactive 2-¹⁸[F]-fluoro-deoxy-D-glucose analogue.

Xi Chen, Xiaoying Fan, Yuzheng Hu, Chun Zuo, Dost Ongur, Fei Du

The resting-state functional connectivity (rsFC) and task evoked fMRI, involving the default mode network (DMN) and control network (CN) was performed, with GABA, glutamate and glutamine measured at MPFC and DLPFC, in order to explore the underlying molecular mechanism of the DMN-CN interaction. We found that MPFC GABA concentrations significantly modulate DMN deactivation during a working memory task, and resting state anti-correlation between DMN and CN, while DLPFC GABA correlations modulate DMN-CN anti-correlation in the opposite direction. These findings suggest that MPFC and DLPFC GABA make a major but differential impact on task related activation and inter-network rsFC. The neurochemical characteristics of DMN and CN may provide novel insights into abnormal network activity in neuropsychiatric diseases and provide opportunities for novel interventions.

Ana Pereira, Xiangling Mao, Caroline Jiang, Guoxin Kang, SAra Milrad, Bruce McEwen, Ana Krieger, Dikoma Shungu

Sleep-disordered breathing (SDB) is a disorder characterized by repeated episodes of hypopnea and apnea during sleep that lead to sleep fragmentation and intermittent hypoxia. A leading model of model of SDB that posits GABAergic and glutamatergic dysregulations that lead to hyperexcitability and neuronal damage, which this study aimed to investigate using J-edited MRS and polysomnography. The main results were a robust DLPFC GABA decrease and associations between GABA and hypoxia as well as disease severity. The state of hyperexcitability observed in SDB is interpreted as likely the result of disinhibition (GABA) that might lead to excitotoxicity and neuronal damage.

Margaret Lentz, Anna Honko, Jordan Bohannon, Matthew Lackemeyer, Jeffrey Solomon, Louis Huzella, Gene Olinger, Lisa Hensley, Peter Jahrling

The purpose of this study was to use MRI and magnetic resonance spectroscopy (MRS) to determine if structural or metabolic alterations occur in the brain of rhesus macaques exposed to Ebola virus via inhalation of aerosolized small particles. Unlike intramuscular inoculation with Ebola virus, small-particle aerosol exposure of macaques did not result in uniform changes in brain volume or vascular alterations 8-9 days after exposure.  However, most animals had reductions in N-acetyl aspartate and increases in choline levels, indicating spectroscopy may be useful in identifying early alterations in brain metabolism due to Ebola virus disease.

Thomas Johnson, James Rogers, Jeff Dunn

Cerebral metabolic rate for oxygen (CMRO₂) in gray matter (GM) is a sensitive marker for abnormalities in oxidative metabolism. We combined a near-infrared spectroscopy (NIRS) system with 9.4.T MRI to quantify regional CMRO₂ in the experimental autoimmune encephalomyelitis (EAE) mouse model of multiple sclerosis. Increases in CMRO₂ were seen in EAE mice and positive inflammation (CFA) controls at day 35 post-induction when compared to naïve controls. In addition, EAE and CFA mice showed increased CMRO₂ from day 14 to 35. These data indicate that inflammation alone, not necessarily linked to a white matter autoimmune disease, could cause abnormal CMRO₂ in GM.

Emilie Poirion, Benedetta Bodini, Marco Battaglini, Theodore Soulier, Léorah Freeman, Daniel Lorenzo-Garcia, Géraldine Bera, Michel Bottlaender, Bruno Stankoff

We explored the neuronal component of grey matter damage in the earliest phase of multiple sclerosis (MS) with [¹¹C]Flumazenil positron emission tomography (PET). Using a novel post-processing approach based on the generation of individual maps of neuronal pathology, we found a significant neuronal damage in the cortical lesions of patients with MS which preceded the occurrence of cortical atrophy, and correlated with white matter lesion load. These results suggest that cortical demyelination, together with retrograde degeneration of transected axons within white matter lesions, are among the key pathogenic contributors to neuronal cortical damage at the earliest stage of the disease.

Ian Marshall, Michael Thrippleton, Mark Bastin, Daisy Mollison, David Dickie, Francesca Chappell, Scott Semple, Annette Cooper, David Miller, Sue Pavitt, Gavin Giovannoni, Claudia Gandini Wheeler-Kingshott, Bhavana Solanky, Christopher Weir, Nigel Stallard, Clive Hawkins, Basil Sharrack, Moira Ross, Jeremy Chataway, Peter Connick, Siddharthan Chandran, the MS-SMART trialists

¹H MR Spectroscopy yields metabolic information and has proved to be a useful addition to structural imaging in neurological diseases. We applied short-TE Spectroscopic Imaging combined with linear modelling with respect to brain tissue type in a homogeneous cohort of 42 patients with Secondary Progressive Multiple Sclerosis. Metabolite levels were significantly different in lesions compared with normal appearing tissues, suggesting axonal damage (reduced NAA) and increased glial activity (increased myo-inositol) yet relatively stable lesions (reduced Glx).

 

 

James Joers, Dinesh Deelchand, Tianmeng Lyu, Uzay Emir, Diane Hutter, Christopher Gomez, Khalaf Bushara, Lynn Eberly, Gulin Oz

We investigated the sensitivity of ultra-high field MRS to distinguish 4 hereditary neurodegenerative diseases with substantial overlap in clinical presentation and conventional MRI. We carried out pairwise classifications of spinocerebellar ataxias (SCAs) 1,2,3 and 6 using distance weighted discrimination (DWD) on 7T MRS from 3 brain regions of 68 SCA patients. Each subject contributed to the DWD model a 50-dimensional vector of concentrations. SCA6 was classified from SCAs 1-3 with high reliability (90%) and SCA2 was classified from SCA3 with moderate success (84%), while SCA1 could not reliably be classified from SCA2 (62%) or SCA3 (48%) with the current model.

Devashish Das, Aneurin Kennerley, Samuel Harris, Jason Berwick

Permissive hypercapnia is commonly used as vasodilatory challenge in clinical applications and basic research. During fMRI experiments continuous exposure to mild (3-10%) CO2 can be applied to derive stimulus induced changes in the cerebral rate of oxygen consumption (CMRO2) by measuring cerebral blood flow and blood oxygenation dependent (BOLD) signal. Previous data from anesthetized primate during hypercapnia suggested increase in CBF are accompanied by decreases in neuronal activity. In this context, using multinuclear (31P/1H) and multi-parametric MR  we show that mild exposure to hypercapnia elevates regional CBF, and can cause marginal but consistent drop in intracellular pH of rat  brain, despite constant [ADP ~25-35µM] and [ATP ~3-2.4mM]  to that of resting  brain. Our findings support the view that unspecific drop in brain pH may likely elevate regional CBF, thereby sustain oxygen supply-to-demand ratio in rat brain.

Xueying Ma, Dun Ding, Peng Li, Fengli Liang, Zhuonan Wang, Yingxiang Sun, Haining Li, Ming Zhang

Restless legs syndrome (RLS) was very common among ESRD patients. However, the physiopathologic mechanisms of RLS in ESRD patients were largely unclear. Here we analyzed the thalamic metabolites using 1H MRS and the correlation between sleep/RLS score and metabolites, compared with corresponding normal controls. The results showed that the Cho/Cr ratio increased and NAA/Cr ratio decreased in thalamus of ESRD patients. The correlation between Cho/Cr ratio and RLS score was significant. It indicated that the sleep disturbance in ESRD patients with RLS might be associated with the abnormal thalamocortical activation of human sleep regulation system.

Devashish Das, Aneurin Kennerley, Samuel Harris, Jason Berwick, Devashish Das

Permissive hypercapnia is commonly used as vasodilatory challenge in clinical applications and basic research. During fMRI experiments continuous exposure to mild (3-10%) CO2 can be applied to derive stimulus induced changes in the cerebral rate of oxygen consumption (CMRO2) by measuring cerebral blood flow and blood oxygenation dependent (BOLD) signal. Previous data from anesthetized primate during hypercapnia suggested increase in CBF are accompanied by decreases in neuronal activity. In this context, using multinuclear (31P/1H) and multi-parametric MR  we show that mild exposure to hypercapnia elevates regional CBF, and can cause marginal but consistent drop in intracellular pH of rat  brain, despite constant [ADP ~25-35µM] and [ATP ~3-2.4mM]  to that of resting  brain. Our findings support the view that unspecific drop in brain pH may likely elevate regional CBF, thereby sustain oxygen supply-to-demand ratio in rat brain.

Heather Gray-Edwards, Elise Diffie, Ashley Randle, Amanda Gross, Nouha Salibi, Lauren Ellis , Ronald Beyers, Miguel Sena-Esteves, Thomas Denney, Douglas Martin

Tay-Sachs Disease (TSD) is a fatal neurodegenerative disorder of children and the sheep model of TSD is a powerful tool to study the disease and evaluate novel therapies.  One such therapy, adeno associated viral (AAV) gene therapy has resulted in a 2-fold increase in lifespan and biomarkers are needed for clinical trials.  7T MRI shows white and gray matter alterations and MR spectroscopic abnormalities that worsen with TSD disease progression.  At humane endpoint the AAV treated sheep has normalization of gray and white matter intensities, but cortical atrophy and MRS alterations persist.   7T MRI and MRS reflect TSD disease severity.  

Pallab Bhattacharyya, Micheal Phillips, Lael Stone, Mark Lowe

Gamma aminobutyric acid (GABA), a major inhibitory neurotransmitter, has been implicated as a metabolic marker of multiple sclerosis (MS). Previously it has been shown that sensorimotor cortex GABA level is higher in relapsing remitting MS (RRMS) patients with poorer motor performance. In this study, the association between cortical GABA level and motor performance, as measured by 9-hole peg test score, has been studied for groups of patients with RRMS with different degrees of motor impairment. The results suggest that cortical GABA has more involvement in motor performance in early stage of RRMS or in less impaired patients.

Yuki Kanazawa, Masafumi Harada, Mitsuharu Miyoshi, Yuki Matsumoto, Hiroaki Hayashi, Toshiaki Sasaki, Natsuki Ikemitsu

The purpose of this study is to assess the CEST effect and contrast of various brain regions in normal for phase cycle-CEST MR imaging. Subjects were five healthy volunteers. All slice positions were set on the nucleus basalis level. ROIs were set as thalamus, frontal, occipital, putamen, and gray matter on right and left brain hemispheres of each subject There was no significant difference in mean MTR_asym values among each brain region (P > 0.01 for all). CEST effects for normal brain tissue had no dependency on region and/or left-right hemispheres.

Jimin Ren, Ty Shang, A. Dean Sherry, Craig Malloy

³¹P MRS is capable of probing cerebral metabolism in vivo, but clinical applications are limited by poor spatial resolution. This study demonstrates that ³¹P MRS imaging (MRSI) at 7T can offer high quality spectral data that enables cross-sectional mapping of various phosphorus-bearing metabolites in normal human brain. In a patient with prior ischemic stroke,  high-energy phosphates were depleted and extracellular inorganic phosphate was increased in the stroke lesion. 

Bretta Russell-Schulz, Andrew Yung, Austin Hill, Alex MacKay, Piotr Kozlowski, Blair Leavitt

Two Huntington’s disease (HD) mouse models with difference rates of disease progression, zQ175 and YAC128, were examined using 7T proton magnetic resonance spectroscopy of mice aged 6-7 months. zQ175 heterozygous and homozygous genotypes showed significantly decreased [tNAA] and increased [mI] compared to wild type. No differences in metabolite concentrations were found between YAC128- (wild type) and YAC128+ mice. A slow HD disease course in YAC128+ genotype may be the reason for lack of measured metabolite concentration differences.

Ahmad Seif Kanaan, Alfred Anwander, Andreas Schäfer, Berkin Bilgic, Torsten Schlumm, Jamie Near, Kirsten Müller-Vahl, Harald Möller

We use a combination of Quantitative Susceptibility Mapping and 1H-MRS to examine the role of iron and its association with glutamatergic signalling in Gilles de la Tourette syndrome (GTS). GTS is a neurodevelopmental movement disorder with abnormalities in the neurotransmission of dopamine and GABA and, as shown more recently, also in subcortical glutamate (Glu) and glutamine (Gln). In this work, we observed that GTS patients exhibit reductions in cerebral iron levels and report a general association between iron and the Gln:Glu ratio. This work provides a good example of utilizing multi-modal neuroimaging methods to interrogate pathophyiology at multiple scales.

Golam Chowdhury, Peter Dixon, Robin de Graaf, Xiaoxian Ma, Johnson Johnson, Jeffrey Johnson, Larry Park, Gerard Sanacora, Douglas Rothman, Kevin Behar

Alterations in brain glucose and energy metabolism is observed in Huntington’s Disease (HD) and HD animal models. 1H-[13C]-MRS can be readily adapted to measure metabolic pathway flux by use of 13C-labeled substrates. In this study we assessed whether activation of the astroglial Nrf2-ARE pathway in the R6/2 mouse model of HD, which has shown therapeutic potential in HD animal models, can reverse the reduction in 13C labeling seen previously in R6/2 mice. In cortex and striatum, astroglial Nrf2 activation led to increased amino acid 13C labeling, suggesting a degree of improvement in mitochondrial and neurotransmitter fluxes in the R6/2 mice.

Mingming Zhu, Alice Shum-Siu, Emily Martin, Abby Wade, Darlene Burke, David Magnuson, Chin Ng

We measured the profile of major metabolites longitudinally using MRS in spinal cord gray matter of  kainic acid (KA) injured rats at both 7 and 14 days post KA administration and correlated their concentrations with functional outcomes assessed by the Basso, Bresnahan, and Beattie (BBB) Open Field Locomotor scores. Our preliminary findings indicate that metabolite concentrations in the lower lumbar spinal cord gray matter, caudal to the injury epicenter, as detected by in vivo 1H-MRS, could be used as injury and recovery biomarkers in SCI animal models.

Yiran Chen, Byongsop Lee, Robert Bok, Ilwoo Park, Subramaniam Sukumar, R Sheldon, A Barkovich, Donna Ferriero, Duan Xu

In this study, we applied dynamic nuclear polarization (DNP) technique to investigate C1 labeled ¹³C pyruvate to lactate conversion on hypoxic ischemia (HI) injured neonatal mouse brains during development. Our results showed that lower pyruvate level and higher lactate to pyruvate ratio on the injured hemisphere in comparison to the non-injured hemisphere at the day of injury (P10). This difference narrows as the brain matures. With this technique, we are able to examine individuals’ response to HI in vivo during brain development.

Yuxue Dang, Xiaoming Wang, Kaining Shi

The excitotoxicity of glutamate metabolism as well as hemodynamic disorders of the brain are both risk factors for neonatal hypoxic–ischemic brain damage (HIBD). To investigate the combined application of intravoxel incoherent motion (IVIM) and ¹H-magnetic resonance spectroscopy (MRS) in exploring the possible mechanisms. This study was undertaken to examine basal ganglia metabolites (by means of ¹H MRS) and microcirculation (by means of IVIM) in a piglet model of hypoxic-ischemia (HI). It is concluded that elevation of glutamate occurs in parallel to perfusion disruption reflected by changes in perfusion fraction f after HI.  

Ana Rodríguez-Soto, Yulin Chang, Wen Cao, Zachary Rodgers, John Detre, Erin Englund, Sarah Leinwand, Richard Schwab, Michael Langham, Felix Wehrli

Obstructive sleep apnea (OSA) is a chronic disorder caused by intermittent obstruction of the upper airways during sleep. Neurocognitive deficits in this population have previously been associated with altered brain metabolism. In fact, a recent pilot study suggests that global cerebral metabolic rate of oxygen (CMRO₂) may be a potential marker of oxygen metabolic dysfunction in this population. Here, we present preliminary results from an ongoing study designed to quantify CMRO₂ in subjects with OSA and matched controls. Initial results suggest that apneics have overall lower baseline CMRO₂ and increased response to volitional apnea, a paradigm to mimic spontaneous apneas. 

Thomas Mueggler, Andreas Bruns, Laurence Ozmen, Herve Schaffhauser, Basil Künnecke, Markus von Kienlin

In contrast to transgenic models of Huntington’s disease (HD) newly available knock-in models, such as the HttQ175, recapitulate the heterozygosity present in the clinically observed pathophysiology. Here we report a longitudinal assessment of striatal metabolites using 1H-MRS and volumetry in 30+ brain regions in both male and female HttQ175 mice. Apart from a genotype-specific, progressive neurodegenerative phenotype present in both genders, we discovered an entirely novel feature in mouse models of HD, namely individuals with abnormally high glutamine (Gln) levels, whose incidence increased with mutant Htt gene dosage. In line with emerging data on a widespread peripheral metabolic perturbation in HD, we hypothesize that this excessive Gln is a consequence of disordered hepatic metabolism.

Tao Gong, Guangbin Wang, Richard Edden, Fei Gao, Yuanyuan Xiang, Weibo Chen

This study was aimed to evaluate the differences between PD motor subtypes of GABA+ levels using MEGA-PRESS. PD patients were classified into PIGD and TD groups; sixteen healthy controls were recruited. All subjects underwent 3T MR examination including MEGA-PRESS. We found that GABA+ concentration was lower in PD compared with controls; furthermore, the TD group was lower than PIGD. In PD patients, the GABA+ levels were correlated with UPDRS scores. The results suggest that GABAergic dysfunction may play an important role in the pathogenesis of Parkinson’s disease. MEGA-PRESS provides a valuable examination method to discriminate between PD motor subtypes. 

Sune Darkner, Søren Jønsson, Stefan Sommer

We present the first MRI-based study of the anatomy of the human outer ear. We show that on 45 subjects we can accurately retrieve the anatomy of this outer cavity using a focussing coil, a T2-weighted sequence and vegetable oil. As validation, we show that from the retrieved anatomies of the population we can, using standard methodology, compute an average ear canal that has distinct anatomical landmarks as well as the acoustical properties, which are almost identical to that of a real ear-canal anatomy.

Isabella Klasinc, Kathrin Ogris, Thomas Ehammer, Thomas Widek, Thorsten Schwark, Eva Scheurer

Former studies have already shown, that MRI findings in victims after survived strangulation allow the diagnosis of strangulation. Native 3T MR scans of the neck were performed in strangulation victims without external findings. All subjects showed strangulation specific MRI findings. Therefore, MRI of the neck is indicated in cases of reported manual strangulation. 
 

Meng Lin, Xiaoduo Yu, Bing Wu, Dehong Luo, Han Ouyang, Chunwu Zhou

Assessment of perfusion is important in tumor diagnosis, stage and therapeutic effect evaluation. This study aimed to investigate the relationship between arterial spin labeling (ASL) (with PLD=1.0, 1.5 and 2.0s) and DCE-MRI parameters of nasopharyngeal carcinoma (NPC). Two observers measured the tumor blood flow (TBF) by ASL and DCE derived parameters including MaxSlop, CER, IAUGC, Ktrans, Kep and Ve. TBF showed moderate to strong correlations between all three TBF and DCE-MRI parameters except between all TBF with Ve and between TBF of PLD1.5s and CER. ASL is a feasible non-invasive tool in NPC to quantitatively assess the perfusion.

Toshitada Hiraka, Masafumi Kanoto, Yuuki Toyoguti, Yoshihiro Konno, Yasuhiro Sugai, Takaaki Hosoya

Non-echo planar imaging diffusion-weighted imaging (nEPID) is a useful tool for diagnosing middle ear cholesteatoma. The cut-off value of nEPID has not yet been determined, however, as fused thin-slice nEPID and computed tomography (nEPID-CT) color imaging cannot correctly distinguish cholesteatoma from other soft tissue. We examined the detectability of cholesteatoma with nEPID using nEPID-CT color images obtained as preoperative studies. The appropriate cut-off value of the signal intensity ratio on nEPID is 0.925 on the receiver operating characteristic (ROC) curve with Youden’s index. Here, we evaluate the efficacy of nEPID-CT color images based on this nEPID cut-off value.

Chien-Yuan Lin, Jianxun Qu, Ai-Chi Chen, Yen-Chien Wu, David Yen-Ting Chen, Ying-Chi Tseng, Chi-Jen Chen

Pseudo-continuous arterial spin labeling (pCASL) has been recently used for investigating cerebral hemodynamic change on the patient receiving carotid artery stenting (CAS) because it permits repeated measurement of absolute cerebral blood flow in a short interval without MR contrast agent or radioactive material. However, labeling efficiency of pCASL has been proved to be dependent on B₀ and B₁ inhomogeneity. The aim of this study was to understand how inhomogeneous of the B₀ and B₁ at labeling position of pCASL and find the remedies of the pCASL measurement for the CAS patient.

Kingkarn Aphiwatthanasumet, Gerry O'Donoghue, Paul Glover, Xiao Liang, Penny Gowland

Despite the promise of increased sensitivity, non-contrast-enhanced imaging of inner ear at 7T is challenging due to local variations in B1 and B0. Here we optimize T2-weighted scanning to improve image quality in the inner ear and evaluate the normal variation in the geometry of the cochlea using 3D T2W DRIVE sequence with dielectric pads and RF shimming. The resulting images show well-defined internal structure of the cochlea and the branches of cranial nerve. 

Dechun Zheng, Yunbin Chen, Meng Liu, Hao Lin, Xiaoxiao Zhang, Qiuyuan Yue, Wang Ren, Weibo Chen, Queenie Chan

Many quantitative DCE-MRI based studies suggested it had utility in early monitoring radiotherapy and chemotherapy sensitivity in anti-tumor treatment. However, there are a few studies investigated whether it could been used for predicting IMRT effect and to what extend of its performance would be. This study enrolled 87 patients who received DCE-MRI one week before NAC and one week after IMRT treatment and suggested there were collaboration the kinetic parameters of quantitative DCE-MRI in early assessing IMRT treatments in NPC.

Lan Zhang, Wen Chang Chen

Imaging the brachial plexus is a challenge due to its complicated structure. The purpose of this study is to improve the diagnosis ability for brachial plexus 3D-STIR-SPACE technique with contrast agent administration. After contrast agent administration, signals of adjacent vessels were suppressed due to reduction in its T1 relaxation time which became similar to that of fat. The outlines of nerves would be clearer with respect to surrounding tissues.The image of 3D-STIR-SPACE technique with contrast agent was superior to that without contrast agent. It might be a better way to evaluate anatomies and pathologies of the brachial plexus.  

Nao Kajihara, Tomohiko Horie, Syuhei Shibukawa, Susumu Takano, Toshiki Saito, Makoto Obara, Tetsuo Ogino, Tetsu Niwa, Yutaka Imai

Dynamic improved motion-sensitized driven-equilibrium steady-state free precession (dynamic iMSDE SSFP) has been introduced to visualize the irregular flow of cerebrospinal fluid (CSF), which obtains this data in 2D. To improve visibility of CSF space at a wide range, we here proposed a new technique using 3D-free factor. The results showed that fluid motions were sensitively suppressed by iMSDE, similar to 2D acquisition. Thus, this technique may detect irregular CSF motion at the wide range.

Jing Yuan, Yihang Zhou, Oilei Wong, Winky Wing Ki Fong, George Chiu, Kin Yin Cheung, Siu Ki Yu

Investigation of positional and geometric variations of organ-at-risk (OAR) in head-and-neck (HN) radiotherapy (RT) is greatly limited by the poor soft tissue contrast of X-ray-based imaging. We investigated the positional variation of parotid glands (PG) in the immobilized HN-RT treatment position on healthy volunteers using high-spatial-resolution 3D-MRI at 1.5T. The results showed that PGs generally had sub-millimeter and sub-degree group mean error, systematic error and random error under immobilization. Although PGs generally showed insignificant positional variations from global HN, individual left and right PG might move independently and resulted in insignificant positional correlations with each other and global HN.

Katsuhiro Inoue, Maki Umino, Ryohei Nakayama, Shinichi Takase, Tsunehiro Yamahata, Makoto Obara, Masayuki Maeda, Hajime Sakuma

Evaluation of parotid blood flow (PBF) may provide an insight into the pathophysiology of parotid diseases. We evaluated and compared the blood flow of normal parotid glands in six volunteers using 2D-echo-planar (EP) and 3D-turbo-spin-echo (TSE) pseudo-continuous ASL (pCASL) sequences. Visual assessment indicated that 3D-TSE pCASL maps were significantly better for delineating normal parotid glands. 3D-TSE pCASL showed larger PBF values than 2D-EP pCASL. Fewer measurement errors were observed in 3D-TSE pCASL data. We concluded that 3D-TSE pCASL is more suitable for the evaluation of PBF than 2D-EP pCASL.

Yu-Chia Cheng, Yi-Jui Liu, Yi-Hsiung Lee, Hing-Chiu Chang, Hui-Chu Chiu, Ta-Wei Chiu, Kang Hsu, Hsian-He Hsu, Chun-Jung Juan

The parotid gland function is evaluated by gustatory stimulation using scintigraphy in clinic. It is supposed to measure the water component of parotid gland using PD MRI instead of scintigraphy. In this study, we initially developed the evaluation of parotid gland function by PD MRI, and 10 healthy volunteers underwent double echo EPI with gustatory stimulation. Maximal drop ratio (MDR), time to peak (TTP), drop slope (DS), recovery slope (RS) and recovery ratio (RR) were calculated. The signal intensity dropped significantly after gustatory stimulation on PD image (P<0.01). MRI allows quantification of parotid gland function using semi-quantitative functional parameters.

Yusuke Yokota, Yasutaka Fushimi, Tomohisa Okada, Akira Yamamoto, Tsutomu Okada, Aurelien Stalder, Christoph Forman, Michaela Schmidt, Kaori Togashi

The aim of this study is to perform a comparison between 3D pituitary dynamic study using time-resolved angiography with interleaved stochastic trajectories (TWIST) and TWIST with iterative reconstruction (IT-TWIST). IT-TWIST was retrospectively reconstructed from the raw data of TWIST by using L1 wavelet regularization in space and time. One neuroradiologist put regions of interest in pituitary stalk and anterior lobe and made time intensity curve. The slope of enhancement in the early phase was evaluated. In addition, image quality was visually evaluated. IT-TWIST yielded higher slope of enhancement in the early phase in anterior lobe and better image quality.

Miran HAN, Jin Wook Choi, Su Jin Lee

We evaluated association between perfusion/diffusion MRI parameters, metabolic ¹⁸F-FDG PET parameters and HPV status in not only primary oral cavity-oropharyngeal squamous cell carcinoma but also its metastatic lymph nodes. Any significant difference was not found in quantitative perfusion, diffusion, metabolic parameters of primary tumor between HPV-positive and HPV-negative groups. In case of metastatic lymph node, only metabolic parameters were significantly higher in HPV-positive group. In our study population, HPV status of primary OC-OPSCC and metastatic lymph nodes did not translate into different perfusion/diffusion parameters. Larger study population is needed to establish whether imaging parameters can represent the HPV status.

Samantha By, Ed Mojahed, Saikat Sengupta, Seth Smith

Spinal cord DTI is technically challenging, primarily due to the small size of the cord and physiological motion. We compare three different sequences to address these challenges: 1) single-shot EPI (ss-EPI), 2) multi-shot EPI with 2D navigation (IRIS), and 3) multi-shot EPI with reduced FOV (IRIS+iZOOM). Results indicate that IRIS alleviates geometric distortion present in ss-EPI. The combination of IRIS and iZOOM, however, provides the most consistent and least distorted diffusion-weighted images.  These effects are clearly seen in the fractional anisotropy, axial diffusivity, and radial diffusivity maps, where exceptional contrast between gray and white matter are observed with IRIS+iZOOM.

Ola Norbeck, Enrico Avventi, Henric Rydén , Stefan Skare

We propose a simple method to suppress cerebrospinal fluid pulsatile-flow-artifacts in axial 2D T1-weighted spin-echo images of the spine. Widening the spatial width of the excitation pulse is shown to remove artifacts that otherwise could obscure or mimic tumors in the spinal canal.

Kinya Ishizaka, Kohsuke Kudo, Kuniaki Harada, Toru Shirai, Taro Fujiwara

To evaluate the homogeneity of B1+ and signal intensity of the thoracolumbar spine with different arm positions. Twenty volunteers were scanned with 4-channel RF transmit coil at 3T. Three arm positions were used; arms on the bed, arm lift, and arm up position. Axial B1+ maps and sagittal T1WI were obtained individually with each arm position. Mean and SD values of FA, and CNR with arm lift and arm up position were significantly superior with arms on the bed position. Inhomogeneities of B1+ and signal intensities were improved by simply changing the arm position at 3T thoracolumbar spine imaging.

Satoshi Maki, Benjamin Conrad, Robert Barry, Lydia McKeithan, John Gore, Seth Smith

 In spinal cord functional magnetic resonance imaging (fMRI) studies, localization of functional activation is still limited due to low signal to noise ratio and low spatial resolution. We studied blood oxygen level dependent signal changes in individual gray matter horns of the cervical spinal cord using a 3D gradient-echo sequence for fMRI during an upper extremity motor task. Visualization and delineation of neural activity in gray matter of cervical spinal cord elicited by the motor task was successfully demonstrated at fine spatial scales suggesting the potential for noninvasive monitoring of spinal cord function.

Martina Liechti, Nuttakarn Budtarad, Daniel Altmann, Xixi Yang, Ahmed Toosy, Jalesh Panicker, Claudia Gandini Wheeler-Kingshott, Marios Yiannakas

Spinal cord (SC) atrophy as a consequence of neurodegeneration, and its association with clinical scores of disability, may be assessed indirectly by means of cord, grey matter (GM) and white matter (WM) segmentation from magnetic resonance images. Neuropathological evidence suggests that in certain neurological conditions, early degeneration may occur as low as the sacral SC, potentially implicating neural pathways that are essential for the functioning of the lower urinary tract. In this work, the feasibility of GM/WM segmentation of the conus medullaris is assessed in vivo using a clinical 3T system.

Matthew Budde, Nathan Skinner, Brian Schmit, Shekar Kurpad

Diffusion tensor imaging (DTI) of the spinal cord remote from the site of injury has been shown to be a surrogate marker of spinal cord injury (SCI) severity.  In this work, detection of injury severity with in vivo diffusion MRI of the rat cervical cord following a thoracic SCI was improved with advanced diffusion MRI signal modelling compared to DTI.

Gergely David, Eveline Huber, Nikolaus Weiskopf, Siawoosh Mohammadi, Patrick Freund

Neuroimaging of the cervical cord has demonstrated above-level neurodegeneration after traumatic spinal cord injury. In this study, we investigated below-level neurodegeneration with optimized high-resolution MRI sequences, including diffusion tensor imaging and structural imaging, applied to the lumbar cord in patients with cervical injury. Our results demonstrate that atrophy and axonal degeneration are prominent in the lumbar cord reflected by structural and diffusivity changes. Furthermore, the extent of these changes is related to clinical impairment. This study shows neurodegeneration below the level of injury and demonstrates the clinical feasibility of acquiring readouts of tissue-specific changes in the lumbar cord.

Eveline Huber, Gergely David, Niklaus Weiskopf, Siawoosh Mohammadi, Patrick Freund

We studied the extent of cervical grey and white matter neurodegeneration above the level of injury after traumatic spinal cord injury (SCI) using high-resolution structural and diffusion MRI data. We found marked atrophy of both white and grey matter alongside diffusivity changes associated with axonal degeneration within the major spinal tracts. The extent of structural decline related to clinical impairment. These tract specific changes and clinicopathological relationships shed light into underlying neurodegenerative disease mechanisms, and therefore these measureable changes hold potential to serve as neuroimaging biomarkers of cord pathology.

Tomohiro Takamura, Ryo Ueda, Masaaki Hori , Ryusuke Irie, Koji Kamagata, Michimasa Suzuki, Shigeki Aoki

Quantification of disease severity and prediction of postoperative outcome were essential in management of cervical spondylotic myelopathy (CSM). The purpose of this study was to investigate correlation between diffusion metrics, including DTI or NODDI in spinal cord pathways, and the severity of CSM, as well as their predictive ability for postoperative recovery. We elucidated that the disease severity was significantly correlated with FA and ODI, and postoperative recovery correlated with RD and MD. The lateral funiculi and lateral corticospinal tract seemed to be the predominant spinal cord pathway that correlated with disease severity and postoperative recovery.

Rexford Newbould, Paul Matthews

A 1-dimensional MR sequence termed Fine Structural Analysis (fineSA) was applied to the human cervical spinal cord in order to determine if spinal tracts and nerve fibres of the dorsal horn could be identified from the spectral regularity of their myeloarchitecture.   Repeatable 60 μm peaks could be attributed to the dorsal horn as opposed to projective nerve tracts of the cord.  This analysis might be able to identify the loss of neurons via changes in packing density that would be proximal to macrostructural atrophy detectable on more classical MR sequences.

Santi Puch, Paulo Rodrigues, David Moreno-Dominguez, Marc Ramos, Vesna Prckovska

Robust and automated tools such as FreeSurfer or ANTs for brain segmentation and quantification have been of utmost importance in the recent advancements in the Neuroimaging field. However, the reproducibility and variability of their results are often uncertain. In this study, we analyzed their reproducibility and compared their outputs for different brain structures. We observe that both tools give high reproducibility for volumetric studies and give similar results in most of the examined cases. However, in some structures (pallidum, rostral-anterior cingulate) there are more pronounced and significant differences. Our results also indicate slightly better reproducibility of ANTs over FreeSurfer.

Yuki Kanazawa, Masafumi Harada, Mitsuharu Miyoshi, Yuki Matsumoto, Hiroaki Hayashi, Toshiaki Sasaki, Natsuki Ikemitsu, Michael Carl

To assess signal of dura mater acquired from UTE imaging, we evaluated this component with T₂^* mapping derived from a multi-echo UTE sequence of healthy volunteers. We then compared measured T₂^* values of cranium and dura mater. The mean T₂^* value of dura mater in five healthy volunteers was significantly higher than that of cranium (P < .05). It is found that the T₂^*decay of dura mater was faster than the cranium components. UTE T₂^* mapping makes it possible to obtain detailed information for meningeal abnormalities.

Seung-Kyun Lee, Seulki Yoo, Anup Bidesi

We investigated scan-rescan reproducibility of human habenula susceptibility measurement using quantitative susceptibility mapping (QSM) at a 0.5x0.5x0.8 mm³ resolution. Although previously reported paramagnetic enhancement in the habenula (Schenck et al., ISMRM 2015) was confirmed, the paramagnetic center was highly localized within the habenula mass to make the susceptibility quantification vulnerable to partial volume effects. This appeared to limit the reproducibility of peak susceptibility measurements in the habenula to 10~40%, with significant variation among subjects. High resolution scans and reliable coil combination of phase data would be needed to make QSM a more reliable tool for human habenula characterization.

Roman Fleysher, Namhee Kim, Asif Suri, Michael Lipton, Craig Branch

Voxel-wise analyses of DTI, fMRI or any other MRI-derived metric, be it for comparing groups or one patient to a control group, require quality registration of images to a template. One or several poorly registered images may skew the distributions of the metric in several voxels leading to incorrect inferences. We propose an approach to screen poorly registered images prior to voxel-wise analysis by comparing subject-wise mean displacements of anatomical landmarks between morphed images and the template estimated using FreeSurfer. We apply this proposed algorithm to demonstrate morph accuracy characterization using two age extreme (18 and 86 year old) templates. 

Ahmed Serag, Emma Telford, Scott Semple, James Boardman

Volumetric analysis of brain MRI acquired across the life course may be useful for investigating long-term effects of risk and resilience factors for brain development and healthy ageing, and for understanding early life determinants of adult brain structure. We developed an automatic segmentation method for human brain MRI, where a sliding window approach and a multi-class random forest classifier were applied to high-dimensional feature vectors for accurate segmentation. The method performed well on brain MRI data acquired from 179 individuals, analysed in three age groups: newborns (38-42 weeks gestational age), children and adolescents (4-17 years) and adults (35-71 years).

Mobeen Ali, Ian Scott, Alain Pitiot, Karen Mullinger, Andy Bagshaw, Penny Gowland, Richard Bowtell

The thalamus plays a major role in regulating the transfer of information through the brain and is also implicated in many neurodegenerative diseases. It is therefore crucial to improve our understanding of this key brain structure. Structural differentiation of thalamic nuclei in post-mortem 7T MRI was investigated. Thalamic sub-regions were identified in magnitude, R2*, R1 and magnetisation transfer ratio maps from six post-mortem brains. Edge detection, k-means clustering algorithms and thin-plate spline warping to the Morel atlas were used to systematically identify thalamic nuclei. These data showed good correlation with stained histological sections and in vivo MRI data. 

Mustafa Irfanoglu, Neda Sadeghi, Amritha Nayak, Carlo Pierpaoli

The availability of anatomically accurate MRI atlases, which can be used as target templates for registration, is essential for quantitative analysis of MRI data. Ideally the computed atlas should be representative of the average features of the population at each voxel location. In this work, we investigate the ability of the most common atlasing approach (i.e. iterative registration followed by averaging) of assuring morphological accuracy. We also evaluate whether constraining the individual deformation fields with deformation-based information helps achieving this goal. We perform our atlas creation tests from full DTI data, using a novel diffusion tensor based diffeomorphic registration technique. We conclude that current atlasing techniques lead to templates that do not faithfully represent the average morphology of the population but that by applying appropriate constraints significant improvements toward this goal can be achieved.

Xiaoxiao Qi, Shengwei Zhang, Konstantinos Arfanakis

The IIT Human Brain Atlas contains anatomical, DTI, HARDI templates, probabilistic gray matter (GM) labels, probabilistic connectivity-based white matter labels, and major fiber-bundles of the young adult brain. During development of the atlas, spatial normalization was accomplished based on diffusion data. Consequently, matching of the anatomical information of T1-weighted images was not maximized, blurring the T1-weighted template and tissue probability maps, increasing the noise of the T1-weighted template, and lowering confidence of GM labeling and GM label precision. The present work enhanced the quality of the T1-weighted template, tissue probability maps, and GM labels of the IIT Human Brain Atlas.

Yuichi Suzuki, Kouhei Kamiya, Minoru Mitsuda, Akira Kunimatsu, Masaaki Hori, Harushi Mori, Katusya Maruyama, Kenji Ino, Yasushi Watanabe, Jiro Sato, Shigeki Aoki, Keiichi Yano, Osamu Abe

We present a preliminary experience of a fiber g-ratio technique using a combination (MT_sat and NODDI) in multi-modal characterization of the white matter bundles relevant to language and hand motor function. Tract-specific analyses of the pyramidal tract, accurate fasciculus, and frontal aslant tract were performed using the tractography as volume of interest.  The fiber g-ratio, MVF, AVF, and FA were measured, and differences between the the hemispheres and among the bundles were tested. This study suggested we can be more sensitive to the lateralities of these bundles by combining myelin imaging and diffusion.

Khin Tha, Kagari Abiko, Yuta Urushibata, Sinyeob Ahn, Osamu Manabe, Naoya Hattori, Kohsuke Kudo, Hiroki Shirato

Gender dimorphism in white matter architecture was evaluated by using DSI and whole brain EPSI. Several white matter areas revealed gender differences in the major DSI indices, of which some area had gender difference in NAA/Cr.

Allen Newton, Isabel Gauthier, Rankin McGugin

Direct visualization of intracortical vascular structure holds promise for detection of pathologic conditions currently invisible with conventional clinical MRI. However, imaging of these structures with MRI has been rare, and no validation of the technique has been performed.  Here, we use 7T SWI to directly image intracortical vasculature on the microscopic scale with the goal of understanding the within and between subject variance. We found intracortical vascular measurements were reproducible within subjects and were sensitive to between subject variability, indicating that the measurements may be useful as a biomarker of disease processes affecting vasculature within the cortex.

Huyen Nguyen, Ulysses Magalang, Amir Abdujiliah, Saba Elias, Petra Schmalbrock, Preethi Subramanian, Shivangi Vora, Wenbo Wei, Samantha Rojas, Kirsten Emmons, David Ribble, Michael Knopp

We aimed to develop a non-invasive quantitative MRI methodology to assess positional and rotational impact on the airway opening in subjects with history of sleep apnea for a proposed clinical trial. An equipment and software analysis approach was implemented to perform a feasibility demonstration using 9 volunteers. All data analysis was performed on IntelliSpace Portal (ISP) (Philips Healthcare) to validate the angles and perform the assessment of the airway opening in the RP and RG regions. We have established a prototype table setup that enables us to image 7 positions of various head and chest support angles to investigate the best positional changes to improve the airway opening of sleep apnea subjects. The results showed that the actual angles were within 0.10-0.30 from the targeted angles. In conclusion, the developed 3T MRI methodology appears robust to assess the impact of head and chest positional changes on the airway in sleep apnea patients. 

Shuqin Zhou, Qihong Zou, Jing Xu, Jiahui Deng, Zihui Su, Tianyi Qian, Thomas Beck, Changwei Wu, Hongqiang Sun, Jia-Hong Gao

Previous animal studies indicated that sleep is important for cell membrane and myelin maintenance in the brain. Research further suggests that variability in sleep structure may be associated with brain white matter microstructure. In this study, we investigate the relationship between sleep structure parameters evaluated with polysomnography and brain white matter characteristics, as measured by MR diffusion tensor imaging. We find that inter-subject variability of regional white matter characteristics may explain the differences in sleep structure across participants.

Olivier Mougin, Prejaas Tewarie, Benjamin Hunt, Nicolas Geades, Peter Morris, Matthew Brookes, Penny Gowland

The aim of this study is to estimate the correlation between myelination in the cortical ribbon and the underlying subcortical WM fibres in healthy adults, using quantitative Magnetization Transfer to assess myelination. The results shows that GM myeloarchitectonic is reflected in the underlying WM in healthy adults. 

Peng Peng, Min Li, Ya-Ru Tian, Yang Yu, Bin Jing, Qing-Lei Shi, Tao Jiang

This study aimed to research the relationship between the volume changes of brain and smoking extent/nicotine dependence. A voxel-based morphometry study between smokers grouped by smoking amount and dependence level was conducted. This study demonstrated the volume of many brain areas decreased with the increase in smoking extent and an opposite correlation between some brain areas and smoking dependence was observed. This study indicated that dependence had limited ability to predict smoking-related brain structure changes. A comprehensive assessment of the situation should be consulted, when clinicians make treatments options.

Debra McGivney, Anagha Deshmane, Chaitra Badve, Dan Ma, Vikas Gulani, Mark Griswold

We apply a partial volume analysis to MR fingerprinting brain tumor data. In the analysis, the number and types of tissues that make up a given voxel are not assumed to be known a priori, which is particularly important in the case of abnormal tissues, such as tumors or edema. We examine the partial volume results in a patient with a glioblastoma multiforme (GBM) and another with a metastasis to look for patterns in healthy tissues, tumor, and the peritumoral region.

Yen-Ning Hsu, Jun-Cheng Weng, Jeng-Dau Tasi, Chao-Yu Shen, Shu-Li Wang

Phthalate esters are a group of chemicals that are widely used everywhere. There is an emerging public health issue that the prevalent use of phthalates may affect children’s brain development. Therefore, we tried to use generalized q-sampling imaging (GQI) to identify the neurological structure changes of white matter of children’s brain induced by prenatal phthalate exposure. The altered GQI indices in the corpus callosum, corona radiata, superior longitudinal fasciculus (SLF), internal capsule, and superior frontal gyrus were found in the children’s brain who were prenatal exposure to phthalate esters.

Charlotte Sleurs, Jurgen Lemiere, Daan Christiaens, Thibo Billiet, Marjolein Verly, Ronald Peeters, Stefan Sunaert, Anne Uyttebroeck, Sabine Deprez

Neurotoxicity of multi-agent chemotherapy in survivors of solid non-CNS tumors during childhood, has limitedly been investigated. Nowadays, diffusion-weighted imaging (DWI) is implemented in clinical studies to examine potential white matter changes. However, standard voxel-based analyses of diffusion measures such as fractional anisotropy (FA), only provide information about local white matter structure on a voxel-level, but lack specific information about fiber populations within a voxel. Therefore, we compared a fixel-based versus voxel-based group comparison analysis of DWI images in survivors of pediatric solid tumor versus healthy age-matched controls. 

J. Scott McNally, Laura Eisenmenger, Seong-Eun Kim, Rock Hadley, Adam De Havenon, Jason Mendes, Gerald Treiman, Dennis Parker

To provide a better method of detection and quantification of carotid intraplaque hemorrhage (IPH), we developed a motion-robust 3D radial stack of stars (SoS) MPRAGE sequence. 3D SoS MPRAGE outperformed 3D TOF in the detection and quantification of carotid IPH when compared with histology. The sequence was robust to motion and flow related artifacts. This sequence, when combined with high-SNR neck shape specific coils, can help identify stroke etiology, determine future stroke risk, and evaluate treatment response by quantifying IPH volume in future clinical trials aimed at decreasing carotid IPH.

A. Max Hamilton, Nils D. Forkert, Runze Yang, Ying Wu, James A. Rogers, V. Wee Yong, Jeff F. Dunn

Grey matter atrophy has become a clinically relevant marker of progressive disability in multiple sclerosis (MS). To better study atrophy in MS, mouse models that have grey matter loss are needed. A possible candidate is the experimental autoimmune encephalomyelitis (EAE) mouse model. We used high-resolution magnetic resonance imaging (MRI) and atlas-based regional volumetrics to measure the volumes of 62 structures in the brains of EAE mice, 66 days post-induction. We identified atrophy in 19 structures including the cortex, cerebellum, striatum, thalamus, hippocampus, and corpus callosum. Using MRI we can study atrophy in this inflammatory model of MS.

Qing Ji, Angela Edward, John Glass, Zoltan Patay, Wilburn Reddick

We proposed a novel robust method to extract the dentatorubrothalamic tract (DRTT) in the human brain from DTI images. First, the method was tested on healthy control subjects, then on 30 medulloblastoma patients who had undergone resection of their posterior fossa tumors. Patterns of bilateral, left only, right only and even no DRTT were observed. Validation with multiple manual ROIs along the known pathway confirmed the extracted DRTTs. This suggests that the proposed method may provide an object way to access the DRTTs in medulloblastoma patients post-surgery.

Günther Grabner, Thomas Haider, Alexander Rauscher, Hannes Traxler, Siegfried Trattnig, Simon Robinson

Image-guided neurosurgery uses information from a wide spectrum of imaging methods which are registered to the patient's skull so that they correspond to the intraoperative macro- and microscopic view at the start of the operation. During neurosurgical intervention the correspondence between imaging and optical systems breaks because of brain shift down. In this study we demonstrate that Susceptibility-Weighted Imaging and automatic vessel segmentation can be used for visualization and segmentation of superficial cortical veins which can be used as additional reference system during operation.

Ross Mair, Andre van der Kouwe

Variations in modern head-coil design lead to sensitivity differences, changes in intensity profiles, and image SNR. As morphometric analysis is based on automated analysis of image intensity and contrast variations, such variation of head coil may be expected to provide variation in morphometric results. We investigated the morphometric results from MEMPRAGE scans on subjects scanned in pairs of different head coils. We saw very limited variation in basic morphometric results from subjects scanned on the same day in different head coils. Cortical thickness variations are generally less than 50 µm, although some larger values were observed in portions of the temporal lobe. Larger differences were observed in volumes of small sub-cortical structures. These structures often have high variability in repeat measurements. However, intensity and SNR variations between coils are often most felt in the deeper regions of the brain, perhaps contributing to wider variation for these structures.

Pierre-Olivier Gaudreault, Julie Carrier, Maxime Descoteaux, Samuel Deslauriers-Gauthier

Sleep spindles, an EEG manifestation generated by the thalamo-cortical loop and implicated in sleep-dependent learning were recently associated to voxel-based metrics of brain white matter. Thus, we aimed to investigate if specific bundles of streamlines underlying the thalamo-cortical loop will be associated to sleep spindles variables in twenty-five young subjects. Our study showed that the median fiber length of streamlines connecting the thalamus to the anterior and middle part of the superior frontal gyrus significantly predicted sleep spindles amplitude and frequency measured on frontal and central electrodes.

Xinbo Xing, Ting Wang, Jinhao Lv, Xiaoxiao Ma, Jiafei Yang, Lin Ma, Xin Lou

As a critical result in different researches the sign of FHV refers to the hemodynamic impairment and slow retrograde flow in leptomeningeal collaterals with or without good clinical outcome. We collected MR imaging data of 32 patients with unilateral ICA stenosis-occlusion who all underwent MR examinations by using 3D tASL perfusion imaging and T2-FLAIR. The tASL perfusion scores were compared between in FVH(-) group (14 patients) and FVH(+) group (18 patients), and there was no difference in the 2 groups. The result showed that 3D tASL perfusion MRI may be a useful non-invasive tool to identify the collateral flow.

Feng Shi, Zhangbin Yi, Qi Yang, Debiao Li, Zhaoyang Fan

Intracranial atherosclerosis is a disease in which a sticky substance called plaque builds up inside the arteries. In practice, plaque analysis based on high resolution MRI is largely conducted manually by neuroradiologists with qualitative results. In this study, we propose a framework for intracranial vessel analysis (IVA), for semi-automatic morphological quantification of intracranial atherosclerotic plaque. Briefly, the framework includes functions of vessel path tracking, 3D MPR, vessel wall segmentation, measurement calculation, and report generation, with minimal user intervention required. Experiments show that plaque existence and location could be easily determined from the resulting vessel wall measures.

Venkatagiri Krishnamurthy, Lisa Krishnamurthy, Michelle Benjamin, Kaundinya Gopinath, Bruce Crosson

Overt speech task functional Magnetic Resonance Imaging (fMRI) paradigms are very attractive to study aphasic patients, but are also plagued by task-correlated motion (TCM). Speech involves movements of the mouth and soft palate, and causes a change in air volume around these areas leading to localized motion and susceptibility artifacts. These artifacts become more severe in patients with Aphasia. The goal of this study is to utilize existing FSL-based semi-automated ICA tools, and optimize them to go beyond removing standard fMRI artifacts by also mitigating TCM artifacts to obtain meaningful hemodynamic response function (HRF) in aphasic patients. Our preliminary results to utilize ICA for TCM-based artifact removal is promising as evidenced by the improved sensitivity and specificity, but needs further optimization. Optimal denoising of overt speech task fMRI in aphasic patients will also help us to delineate their task-based networks in an effort to monitor plastic changes due to language behavior interventions.

Zihao Zhang, Zhaoyang Fan, Chengcheng Zhu, Xinke Liu, Qi Yang, Xianchang Zhang, Qingle Kong, Jing An, Lin Chen

Black-blood MRI (BB-MRI) has been used to evaluate the walls of intracranial aneurysms at both 3T and 7T. However, there is no quantitative comparison between the two field strengths in terms of delineation quality of aneurysmal wall by using BB-MRI. In this study, we analyzed black-blood images acquired from the same group of patients at both 7T and 3T. Higher wall-to-lumen signal ratio (WLSR) and lower inside wall thickness (IWT) were obtained from 7T black-blood images. Our results suggest that 7T BB-MRI can provide improved visualization and measurement of intracranial aneurysmal walls.

Juan Huang, Yan Song, Peng Qi, Sheng Jiao, Hong Wang, Min Chen, Bing Wu

3D TOF MRA is susceptible to hemodynamic artifacts and is not sensitive to the slow blood flow, which results in the unsatisfied image quality for the diagnosis of AVMs. So we compared the use of zero TE ASL MRA (zTE MRA) and traditional 3D-TOF MRA in assessment of AVMs at 1.5T, taking DSA as standard. It was demonstrated that ASL MRA features significantly better consistency with DSA for AVMs as compared to TOF. In detail, zTE MRA can demonstrate the size, internal details, the feeding arteries and draining veins more clearly and accurately compared with TOF MRA.

Hideki Ishimaru, Minoru Morikawa, Reiko Ideguchi, Yohei Ikebe, Masataka Uetani

 Vessel wall susceptibility on SWAN with no calcification on CT indicates intramural hematoma (IMH) associated with vertebral artery dissection (VAD).  The early detection of IMH in VAD can be enhanced with the use of SWAN.

Mengxing Wang, Jingjing Su, Jilei Zhang, Hui Zhang, Jian-ren Liu, Xiaoxia Du*

The purpose of this study was to investigate spontaneous low-frequency fluctuations in CADASIL patients during resting-state fMRI scans. Eleven patients (aged, 33-66 years, 6 female) and 11 age- and gender-matched healthy controls were recruited. Amplitude of low-frequency fluctuation (ALFF) was calculated to measure spontaneous brain activity. The results showed that CADASIL patients exhibited significantly decreased ALFF in the bilateral precuneus, and increased ALFF in the midbrain/ pons, the insula/ temporal pole, and the anterior cingulate gyrus/ corpus callosum. Our study first provides empirical evidence for altered spontaneous neuronal activity in CADASIL patients.

Jérémie Fouquet, Luc Tremblay, Martin Lepage

While standard isoflurane anesthesia does not easily allow visualization of small vessels in mice using T2*-weighted imaging, ketamine/xylazine anesthesia enables the visualization of an impressive fraction of the vasculature, without the need of an external contrast agent. Visualization can be further modulated by modifying the breathing gas.

Raghu Prasad, Jaganathan Vellagoundar, Kathryn McMillan

Evaluation of compressibility and neurodegenerative changes is critical for planning the therapy for ischemic stroke disorders. A key factor that was not analyzed till date is the capillary permeability of blood-brain-barrier (BBB) perturbations and localized mechanical degenerative changes inside the infarct region during ischemic stroke. Our results clearly indicate a decrease in stiffness of stroke-affected infarct tissue. CPI was observed to be less in the weak BBB regions.The results demonstrate through CP and stiffness maps that extent of tissue integrity that is degraded inside the infarcted region can be assessed efficiently

Tzu Cheng Chao, Yu-Chia Cheng, Wen-Chau Wu, Hsu-Hsia Peng, Tzu-Chao Chuang, Hsiao-Wen Chung, Teng-Yi Huang, Yi-Jui Liu

Time-resolved PCMRI has been applied to measure pulse wave velocity (PWV) for the assessment of aortic stiffness. However, longer scan time hinders its practice to achieve a high spatial and temporal resolution scan, especially required for the arteries inside of the head and neck. In the present work, an accelerated Time-resolved PCMRA was implemented to shorten scan time. The reconstruction combines temporal strategy and self-reference information to retain reasonable imaging quality. The results suggest that the proposed method differentiate PWV delay time from Common-Carotid artery to Middle-Cerebral arteries via Internal-Carotid artery with good quality within a 10-minute scan.

Olivia Sobczyk, James Duffin, Adrian Crawley, Kevin Sam, Julien Poublanc, Lashmi Venkatraghavan, Daniel Mandell, David Mikulis, Joseph Fisher

Current methods of measuring cerebrovascular reactivity (CVR) have shown promise for aiding in clinical diagnosis and management of patients with various neurovascular diseases.  However, CVR measurement is currently limited to a research setting and transition to clinical utility requires a universal standardized measurement method.  Using BOLD-MRI CO₂ measured CVR, we present experimentally developed concepts for standardization and post processing, which have the potential to provide a clinically useful brain stress test. 

Chengcheng Zhu, Bing Tian, Sinyeob Ahn, Esther Raithel, Gerhard Laub, David Saloner

Current 3D black-blood high-resolution MRI (0.4-0.6mm isotropic) of intracranial vessel wall is limited by long scan times (~10 minutes). This study implemented a compressed sensing SPACE (CS-SPACE) sequence to reduce the scan time. The scan and reconstruction parameters were optimized in volunteers and then validated in patients. The optimized CS-SPACE protocol achieved good image quality and reliable vessel area measurements compared with SPACE, with a 37% time reduction. 0.5mm isotropic resolution can be achieved in <7 minutes, and 0.6mm³ is possible in 4 minutes. This fast intracranial vessel wall technique has potential for use in a clinical setting.

Jinhao Lyu, Ning Ma, Xiaoxiao Ma, Bing Wu, Lin Ma, Xin Lou

The correlation of fluid-attenuated inversion recovery imaging (FLAIR) vascular hyperintensity (FVH) and collateral are still in discrepancy in intracranial atherosclerotic stenosis or occlusion. In the present study, we used territorial arterial spin labeling (ASL) and two post labeling delay (1.5s and 2.5s) ASL to study the leptomeningeal collateral and hemodynamic status in patients with different intensity of FVH, and concluded that FVH may be related to poor collateralization and hemodynamic impairments.

Seong-Eun Kim, J Rock Hadley, Michael Beck, J Scott McNally, Adam DeHavenon, Bradley Bolster, Jr. , Gerald Treiman, Dennis Parker

Vessel wall MRI(vwMRI) increases diagnostic accuracy for stroke etiologies without overt luminal irregularities, such as mild atherosclerosis, subtle dissection, or vasculitis. Prior vwMRI research has focused on the head or neck in isolation. We developed a set of two neck-shape-specific(NSS) coil that fit two different neck sizes and configured them to integrate with the existing commercial head coils. The purpose of this work was to develop a 3D vwMRI protocol, leveraging the NSS coil array, which permits simultaneous imaging of the head and neck vessels in a single scan. By allowing an efficient examination and identifying patients at high risk of future recurrent stroke, this technique will enable detection of cryptogenic stroke sources and optimal personalized management of vascular disease.

Seena Dehkharghani, Candace Fleischer, Deqiang Qiu, Frank Tong

Temperature dysregulation is deeply implicated in potentiation of cerebrovascular ischemia. We present a multi-phasic, MR thermographic study in a non-human primate (NHP) model of MCA infarction, hypothesizing detectable brain temperature disturbances and brain-systemic temperature decoupling. Successful physiologic and continuous post-ischemic cerebral MR thermography was conducted, and prescribed in an NHP infarction model to facilitate translatability. The results confirm hypothesized temperature disturbance and decoupling of physiologic brain-systemic temperature gradients. These findings inform a developing paradigm of brain thermoregulation, and the applicability of brain temperature as a neuroimaging biomarker in CNS injury.

Makoto Obara, Osamu Togao, Noriyuki Fujima, Shuhei Shibukawa, Masami Yoneyama, Tomoyuki Okuaki, Msanobu Nakamura, Marc Van Cauteren

A new scheme for non-contrast enhanced intracranial three-dimensional dynamic magnetic resonance angiography (4D-MRA) using pseudo-continuous arterial spin labeling (4D-PCASL) is proposed for visualizing inflow and outflow dynamics. The 4D-PCASL procedure was accelerated with contrast-enhanced timing-robust angiography (CENTRA)-Keyhole and the view-sharing techniques (4D-PACK). Images acquired from four volunteers were compared between the 4D-PCASL and 4D-PACK approaches. We show that this new scheme accelerates data acquisition and provides dynamic inflow and outflow information.

Sau May Wong, Jacobus F.A. Jansen, C. Eleana Zhang, Julie Staals, Paul A.M. Hofman, Robert J. van Oostenbrugge, Walter H. Backes

The conventional IVIM model assumes a two-compartment model; this might not apply for regions with enlarged perivascular spaces (PVS) in cerebral small vessel disease (cSVD). Regularized non-negative least squared was used to deconvolve the IVIM signal in multiple diffusion components. Sixty-three cSVD patients and thirty-five controls received IVIM imaging and visual scoring of enlarged PVS. An additional component to the assumed parenchymal and perfusion components was revealed. We show that the fraction of this component is related to the amount of scored enlarged PVS. Quantifying PVS is a time-consuming process and this method might aid the development of automatic quantification.

Alvaro Rojas Villabona, Magdalena Sokolska, Enrico De Vita, Mary Murphy, Thomas Solbach, Joan Grieve, Prem Rangi, Yuriko Suzuki, Matthias JP Van Osch, David Atkinson, Emma Biondetti, Karin Shmueli, Xavier Golay, Ian Paddick, Neil Kitchen, Hans Rolf Jäger

This study investigates whether a combination of three MRA techniques, referred to as triple-MRA, could be used as an alternative to DSA for visualisation and delineation of brain AVMs for GKR targeting. The AVMs of 13 patients undergoing GKR were delineated using triple-MRA and the resultant target volumes were compared to the radiosurgical targets generated by the neurosurgical team using DSA and volumetric contrast T1/T2 imaging. Target volumes obtained using triple-MRA are comparable to target volumes obtained with DSA and used for delivery of GKR. In conclusion, triple-MRA is a robust method for non-invasive identification and delineation of brain AVMs. 

Till Schneider, Markus Möhlenbruch, Sebastian Schmitter, Mark Ladd, Heinz-Peter Schlemmer, Martin Bendszus, Sina Straub

Brain arteriovenous malformations (bAVM) are congenital lesions detected incidentally or following symptomatic events like hemorrhage, seizure or headache. In bAVM patients, the most feared complication is intracranial hemorrhage with a general risk ranging between 2-4%¹ and further functional and hemodynamic characterization of bAVMs may improve risk assessment and ultimately aid in patient management^{2, 3}. In this study, bAVMs have been investigated using quantitative susceptibility mapping and phase contrast based flow measurements. Susceptibility across the bAVM nidus is studied in relation to flow characteristics.  

Chien-Yuan Lin, Ai-Chi Chen, Liang-Yu Shyu, Yen-Chien Wu, David Yen-Ting Chen, Ying-Chi Tseng, Chi-Jen Chen

 

Accurate tracking of plaque composition would be very useful clinically to determine the status of atherosclerosis and to understand the potential risk under myocardial infraction, stroke, and peripheral vascular disease. We developed a semi-automatic software to evaluate the carotid plaque types using four contrast-weighted MRI (pre- and post-contrast T1-weighted, time-of-flight, T2-weighted). Working with the proposed software with the minimal operator input reduces the process time of plaque component identification and minimizes the possibility of random and systematic errors. As a result, proposed software is capable of assisting the radiologist/clinician in imaging interpretation and decision-making in managing carotid artery atherosclerosis. 

Stefan Pszczolkowski, Rebecca Gallagher, Zhe Law, Dewen Meng, David Swienton, Paul Morgan, Philip Bath, Nikola Sprigg, Robert Dineen

In this work, we propose to take advantage of improved contrast seen on magnetic resonance (MR) images of patients with acute spontaneous intracerebral haemorrhage (SICH), and introduce an automated algorithm for haematoma and oedema segmentation from these images. To our knowledge, there is no previously proposed segmentation technique for SICH that utilises MR images directly. The method is based on k-means clustering of image intensities for haematoma segmentation and voxel-wise dynamic thresholding of hyper-intensities for oedema segmentation. Preliminary results using the Dice score metric to measure segmentation overlaps between labellings yielded by the proposed algorithm and five different expert raters show that our technique has the potential to be an effective way to automatically delineate haematoma and perihaematoma oedema extent directly from MR images.

Guodong Song, Min Chen, Chunmei Li, Jinyuan Zhou

This study was performed to investigate the imaging features of Amide Proton Transfer (APT) MR imaging in different subtypes of acute ischemic stroke (AIS) . By figuring out the detailed APTw features in AIS patients, it would be helpful for further clinical applications of APT MRI technique.  

Kayo Takeuchi, Makoto Isozaki, Masayuki Kanamoto, Yoshifumi Higashino, Hidehiko Okazawa, Kenichiro Kikuta, R Lebel, Hirohiko Kimura

Positron emission computed tomography (PET) is used for evaluating cerebral hemodynamic ischemic stages in patients with major cerebrovascular stenosis/occlusion for treatment indication. Using a rapid, low-resolution pre-scan method, arterial transit time (ATT) and corrected cerebral blood flow (CBF) could be obtained, even in the immediate clinical setting. This study aimed to clarify whether ATT is hemodynamically related to misery perfusion stratified with ¹⁵O-H₂O/¹⁵O₂-gas PET data.There was a significant correlation between ASL and PET CBF before and after ATT correction (r²=0.27, 0.55). ATT also significantly correlated with PET-OEF (r²=0.11) and is a useful parameter to classify cerebral ischemia.

Lauri Raitamaa, Vesa Korhonen, Vesa Kiviniemi

Glymphatic pulsation mechanisms clear the brain by using physiological pulsations to drive CSF through the brain tissue. Magnetic resonance encephalography (MREG), an ultra-fast inverse imaging technique, was recently able to map three basic mechanisms driving the glymphatic  brain clearance; arterial pulsations, respiratory venous pulses and slow vasomotor waves. In this study we demostrate that the MREG can also detect changes in the amplitudes of the pulsations driving the clearance. The mapping of the physiological pulsation amplitude changes can be used to quantify changes in glymphatic clearing mechanims that precede neurodegeneration.

Ian Driver, Fabrizio Fasano, Richard Wise

We report the first measurement of venous flow pulsatility in cerebral veins with sub-millimeter diameters using phase contrast MRI. This work exploits the increased signal and finer spatial resolution available at 7 Tesla, over lower field strengths. We suggest that the observed venous pulsatility is a passive response to intracranial pressure changes caused by arterial pulsatility. These measurements may be applied to pathology in which there is compromised venous flow, extending such investigations to the smaller cerebral veins and offering a better understanding of the temporal dynamics of cerebral venous flow.

Ana Rodríguez-Soto, Michael Langham, Felix Wehrli

Susceptometry-based oximetry is a well-established, robust method for quantifying hemoglobin oxygen saturation (HbO₂) in vivo; but the method is somewhat limited by the orientation of the vessel of interest relative to B_o. T₂-based oximetry, based on the dependence of blood water T₂ on HbO₂, provides greater flexibility with respect to vessel geometry. However, the measured T₂ critically depends on B_o and sequence-specific imaging parameters. Here, a T₂-prepared bSSFP sequence and appropriate calibration curve were used to extract HbO₂ at the superior sagittal sinus and the results were compared to susceptometry-based oximetry. The agreement between both methods was excellent with 2% bias. 

Tatsuhiro Wada, Chiaki Tokunaga, Osamu Togao, Yasuo Yamashita, Kouji Kobayashi, Masami Yoneyama, Yasuhiko Nakamura

This study demonstrates a new CSF flow imaging using multi spin echo acquisition cine imaging (MUSACI). MUSACI can obtain the high resolution CSF flow images more than the conventional phase contrast technique, moreover it is simple method because need not use a labeling pulse such as the time-SLIP technique. MUSACI can provide both morphological and physiologic information regarding CSF flow in a single scan.

Dingxin Wang, Gregory Metzger, Kamil Ugurbil, Xiufeng Li

Dynamic frequency feedback to multiband (MB) EPI PCASL excitation, fat saturation, and labeling RF pulse frequency can improve spatial and temporal perfusion signal-to-noise ratio (sSNR and tSNR) and cerebral blood flow (CBF) measurement reproducibility of MB-EPI PCASL. Dynamic frequency feedback helps maintain optimal labeling efficiency, achieve stable fat saturation, and correct scanner drift during MB-EPI PCASL measurements. 

Shu-Juan Fan, Yajun Ma, Graeme Bydder, Jiang Du

Myelin produces ultrashort-lived MRI signals, and cannot be directly imaged using conventional MRI sequences that typically have TEs of several milliseconds or longer. This study explored the potential of inversion recovery ultrashort echo time (IR-UTE) sequences in direct myelin imaging in an ovine brain D₂O exchange model. The IR-UTE signals survived D₂O exchange. Myelin T2* was measured to be 200-300 µs both before and after exchange. These results support myelin to be the major source of the ultrashort T2* signals seen on IR-UTE images, and IR-UTE sequence as a tool for assessing myelin loss in multiple sclerosis and other diseases.

Chou-Ming Cheng, Tzu-Chen Yeh, Jen-Chuen Hsieh, Hsiao-Wen Chung

Venous oxygen saturation (SvO₂) for estimation of global cerebral metabolic rate of oxygen is measured using MR susceptometry from the phase information obtained with multi-echo gradient-echo imaging. Automatic selection and segmentation of the superior sagittal sinus is performed with slice dependent even-odd discrepancy to avoid operator dependency. Results from 12 healthy subjects suggested that phase values of the vessel showing minimal even-odd echo discrepancy could be used as a useful information guiding selection of the appropriate vessel segment for SvO₂ estimations by taking into consideration the three dimensional vasculature. 

Vera Keil, Lars Eichhorn, Burkhard Mädler, Jürgen Gieseke, Frank Träber, Wolfgang Block, Martin Sprinkart, Andreas Müller, Christine Schneider, Lukas Scheef, Hans Schild, Dariusch Hadizadeh, Elke Hattingen

Freedivers can endure severe hypoxemia during breathhold without any apparent neurological deficit. Little is known on how brain circulation adapts to deliberate breathhold. We examined 14 experienced freedivers during breathholds of 5 to 7.5 minutes at a 3T MRI applying 3D-pCASL and IVIM-MRI sequences to reveal dynamic alterations of cerebral blood flow (rCBF) and in order to elucidate the relationship of rCBF and perfusion fraction (PF) of IVIM-MRI. rCBF increased to 3.2-fold the baseline levels and negatively correlated to blood oxygen levels, but not to PF, which initially dropped during breathhold and therefore appears to represent another underlying physiological mechanism.

Se-Hong Oh, Mark Lowe

Because of the much higher SAR and longer acquisition time, patient studies using qMT at UHF have not been clinically feasible. In this work, we demonstrated a new approach (EP-vfMT) for whole brain 7T qMT data in a clinically reasonable time. EP-vfMT provides similar image quality to that obtained with conventional MT imaging, and shortens the scan time by utilizing segmented EPI readout and avoiding from SAR limitation. EP-vfMT generates qMT map in reasonable scan time and it exhibits similar myelin density distribution with qMT result from vdMT and aMWF map from ViSTa. Moreover, it maintains sensitivity to MS lesions.

Francis Tyson Thomas, Jason Su, Brian Rutt, Manojkumar Saranathan

Thalamic nuclei are often hard to visualize on most anatomical sequences. White-matter-nulled MPRAGE imaging provides sufficient intra-nuclear contrast to enable manual segmentation, which is very tedious. We have developed fast multi-atlas based segmentation schemes that can provide accurate segmentation of all the major thalamic nuclei in under 15 minutes.

Lennart Geurts, Alex Bhogal, Jeroen Siero, Geert Jan Biessels, Jaco Zwanenburg

We aimed to measure cerebrovascular reactivity (CVR) specifically at the level of the superficial perforating arteries with 7T 2D Qflow, to develop a method to assess small vessel function for cerebral small vessel disease research. 7T 2D Qflow acquisitions through the semi oval center (CSO) and through the medial cerebral artery (M1) were acquired at baseline and during hypercapnia. CVR_M1 corresponded to CVR values from Qflow literature and, while an order of magnitude smaller, CVR_CSO corresponded to CVR values from ASL literature. This shows proof of concept that CVR of perforating arteries can be measured using 7T 2D Qflow.

Se-Hong Oh, Tiejun Zhao, Ken Sakie, Stephen Jones, Mark Lowe

Improving B₁-uniformity by calibration procedure is crucial for the pTx imaging and commonly individual B₁ coefficient estimation is conducted in the beginning of each patient scan protocol. However, B₁ calibration procedure increase the scan time by approximately 10~15 mins increasing discomfort to the patient.   Here we propose using global B₁ coefficient template to reduce scan time while maintaining acceptable B₁ profile. The approach using global B₁ coefficient template is assumed to have limited inter-individual variation of B₁ coefficient between subjects. We demonstrate the feasibility of scan with global B₁ coefficient template and provide a perception of in-vivo scan with pTx.

Khader Hasan, Refaat Gabr, John Lincoln, Ponnada Narayana

Reliable in vivo quantification and visualization of myelin spatio-temporal changes in the developing and aging human central nervous system (CNS) would help provide important surrogate markers of white matter integrity. However,  high resolution whole brain myelin water fraction (MWF) mapping methods remain challenging and are not well-standardized and are not widely adopted due to ill-posed solutions of the sum-of-exponents problem in the presence of noisy measurements and excessive computation time due to iterative solutions. In this work, we report a rapid method to initialize the solution of the bi-exponential multi-compartment fit which was used along with a host of quality assurance measures to speed up the estimation of the MWF and corresponding compartmental T2 relaxation times using an improved and regularized non-negative least-squares (rNNLS). The sensitivity of the method to signal-to-noise ratio (SNR) and different values of MWF was investigated using a digital phantom. This method was applied to healthy and multiple sclerosis (MS) patients. Our analysis strategy accelerated the accurate mapping of high resolution MWF in the entire human brain in seconds and provided the spatial variability MWF across the corticospinal tract (CST) and callosal pathways.

Ping Wang, Richard Dortch, John Gore

Previous studies have demonstrated that at high fields (3T and beyond), the difference of R_1ρ between low and high spin-locking fields (ΔR_1ρ) may reflect chemical exchange processes in biological tissues.  This study aimed to investigate the possibility of using ΔR_1ρ to assess the content of exchangeable protons in myelin in white matter by comparing ΔR_1ρ with PSR (macromolecular to free pool size ratio from magnetization transfer imaging).  The results show that ΔR_1ρ and PSR have a much stronger correlation in white matter than in gray matter, inferring that ΔR_1ρ might have a potential to evaluate myelin integrity.

Ping Wang, Henry Zhu, John Gore

Previous studies have indicated that R_1ρ (= 1/T_1ρ) dispersion may be dominated by chemical exchange processes at higher fields, and the dispersion may be used to quantify exchange processes between water and labile protons, mainly amides and hydroxyls.  At 3T some biological tissues with high macromolecular protein content may demonstrate a considerable dispersion, but fat and water rich tissues typically have a negligible R_1ρ dispersion.  In this study, we observed that the degree of R_1ρ dispersion in white matter at 7T was more than three times the dispersion at 3T, confirming that chemical exchange is a major contribution to R_1ρ and suggesting R_1ρ dispersion at higher fields may help to characterize tissue physicochemical properties.  

Yang Song, Ehsan Hamtaei, Guang Yang, Haibin Xie, Mark Haacke

We propose a “COnstrained Data Extrapolation” (CODE) algorithm to reconstruct high-resolution MRA images from k-space with a lower resolution thereby accelerating acquisition of the data. We found that CODE can estimate a 50% (70%) stenosis of a vessel with a diameter equal to 7 (10) pixels in the high-resolution image to within 5% of the correct result when the SNR=4:1 or better. Both phantom simulations and in-vivo 3D contrast enhanced MRA data demonstrate that CODE is robust to noise and can be used to speed up conventional data acquisition by a factor of four.

Athena Theyers, Benjamin Goldstein, Arron Metcalfe, Andrew Robertson, Bradley MacIntosh

Arterial pulsatility increases with age and is linked to small vessel damage and neurodegeneration. Our group has developed a method that fits a pulsatility model to BOLD temporal volumes based on their cardiac cycle position. We test this method in a healthy adolescent group before and after a physiological stressor, i.e. 20 minutes of moderate intensity exercise. Brain pulsatility was significantly lower in BOLD scans taken 20 minutes after exercise cessation, supporting the viability of this method to track brain arterial stiffness non-invasively.

Francis Hane, Tao Li, Jane Lawrence-Dewar, Ayman Hassan, Karl Granberg, Raiili Pellizzari, Jennifer Plata, Mitchell Albert

We demonstrate the use of hyperpolarized (HP) 129Xe MRI as a novel fMRI modality. We successfully obtained axial HP Xe fMRI maps from healthy humans throughout the conduct of a 1-back memory task. Our preliminary results suggest that HP 129Xe fMRI may have a sensitivity of up to an order of magnitude more than BOLD fMRI.  

Christoph Birkl, Silvia Budday, Gerhard Sommer, Melanie Bauer, Paul Steinmann, Johannes Haybaeck, Ellen Kuhl, Gerhard Holzapfel, Franz Fazekas, Stefan Ropele, Christian Langkammer

In this study, we investigated the mechanical stiffness of human brain tissue assessed by triaxial testing of post-mortem tissue specimens in relation to magnetization transfer ratio (MTR) and diffusion tensor MRI. Our results showed a strong inverse correlation of MTR and FA with the tissue stiffness. Anisotropy of the stiffness was not observed, which indicates that the neuronal fiber orientation does not mechanically support the tissue.

Paul Weavers, Norbert Campeau, Yunhong Shu, Shengzhen Tao, Joshua Trzasko, Erin Gray, Thomas Foo, Matt Bernstein, John Huston III

A compact, low-cryogen 3T MRI scanner has been developed employing high-performance gradients capable of simultaneously achieving 80 mT/m and 700 T/m/s.  A comparison study of T2-weighted 3D FLAIR in 16 clinical patients graded by two neuroradiologists has been performed.  The compact 3T system performed equally well to a standard whole-body system in terms of motion artifacts and cerebellar folia conspicuity, and performed better in terms of signal-to-noise ratio, lesion conspicuity, gray/white contrast, and overall exam quality.

Koung Mi Kang, Seung Hong Choi, Moonjung Hwang, Ji-hoon Kim, Chul-Ho Sohn, Tae Jin Yun

Although a few studies reported the possibility of Gd deposition in the brain by macrocyclic GBCAs, the final determination of deposition with macrocyclic GBCAs has not been performed. Because Synthetic MRI with MDME sequence enables quantitative measurements with relatively short time, our study aimed to investigate whether T1 relaxation time in globus pallidus was influenced by gadobutrol administrations by using the quantitative MR imaging. This study revealed that T1 shortening in globus pallidus occurs by gadobutrol administrations. Additional studies are needed to investigate the clinical significance of these findings.

Lana Kaiser, Ben Inglis, Hirokazu Kawaguchi, Masaki Fukunaga, Norihiro Sadato, Tomohisa Okada

The goal of this study is to perform an oral glucose tolerance test (GTT) in the healthy human brain tissue in vivo and to evaluate the performance of the recently developed ¹H MRS technique. The observed glucose level curve shape showing increase and washout during the ¹H MRS GTT test is consistent with the medical GTT blood measurements obtained in healthy subjects. This study demonstrates the initial steps towards better understanding of potential utility of ¹H MRS in experiments on glucose metabolism in vivo in the context of nutrition, brain function, and various neurological disorders with impaired glucose utilization.

Yohan Boillat, Pierre-Louis Bazin, Rolf Gruetter, Wietske Van der Zwaag

In this study, the spatial relationship between the somatotopy and the pattern of myelination (as measured by quantitative T₁-maps) in the cerebellum was investigated. Subject-specific surfaces were generated on which were mapped T₁ values and somatotopic maps. Consistent somatotopic gradients organized through several lobules were present in the anterior and posterior lobes. Despite being more complex, changes of T₁ values across the cerebellar surface were also observed and showed a similar orientation as the somatotopic organization. This study showed the potential structure-function relationship of the cerebellum observed at macroscale level.

Peng Cao, Tanguy Boucneau, Peder Larson

Recent study demonstrated a multiple and ultrashort echo time (multi-UTE) MRI method for direct detection of methylene protons in myelin membranes on normal brains. However, such multi-UTE MRI requires prohibitively long scan time; therefore, acceleration method is needed. The objective of this study was to accelerate the multi-UTE imaging in order to reduce the scan time and enable such measurements routinely on our 7T human MRI.