Daniel Jirak¹, Jiri Janacek², and Martin Kundrat^2,3
1IKEM, Prague, Czech Republic, ²Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic, ³Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden

Here we provide a new approach for assessment of encephalic volume of some extinct vertebrates. We used crocodilians as a proxy to investigate the postnatal development of endoneurocranial and encephalic shape in living archosaurs and found noticeable dependence on the body size. Our results support a hypothesis that increased body size likely imposed a new spatial configuration for development of the central nervous system during the evolution of gigantism in tyrannosaurs.

Anne-Kristin Vahle^1,2, Harikrishna Rallapalli^1,2, Artem Mikheev^1,2, Thomas Koesters^1,2, Kai Tobias Block^1,2, Jean Logan^1,2, Timothy Shepherd^1,2, Girish Fatterpekar^1,2, David Faul³, and Fernando Emilio Boada^1,2
1Center for Advanced Imaging Innovation and Research, Dept. of Radiology, New York University School of Medicine, New York, NY, United States, ²Center for Biomedical Imaging, Dept. of Radiology, New York University School of Medicine, New York, NY, United States, ³Siemens Healthcare, New York, NY, United States

The goal of the study was to investigate the use of high-resolution, MR-derived arterial input functions (AIFs) for improving the estimation of tracer kinetic parameters on human brain tumors during dynamic FDG injection without direct arterial sampling. Dynamic PET and MR data was acquired simultaneously during FDG injection. Tracer kinetic parameters were calculated using PET-derived AIFs only or MR-derived AIFs. Bias could be reduced and discrimination between white and grey matter parameters improved when involving MR-derived AIFs for tracer kinetic modeling. Our results suggest that concurrent dynamic MR/PET acquisition could provide more accurate tracer kinetic parameter estimation.

Ileana O. Jelescu¹, Timothy M. Shepherd¹, Dmitry S. Novikov¹, Yu-Shin Ding¹, Thomas Koesters¹, Kent P. Friedman¹, Jacqueline Smith¹, James E. Galvin², and Els Fieremans^1
1Center for Biomedical Imaging, Dept. of Radiology, NYU Langone Medical Center, New York, New York, United States, ²Alzheimer Disease Center, Depts. of Neurology, Psychiatry and Population Health, NYU Langone Medical Center, New York, New York, United States

Along with cortical abnormalities, white matter (WM) microstructural changes are involved in the pathogenesis of AD. We estimate WM Tract Integrity (WMTI) metrics derived from diffusion kurtosis imaging (DKI) in normal aging and amnestic Mild Cognitive Impairment (aMCI). DKI and WMTI metrics in WM ROIs spatially connected to the hippocampus and cortex and/or known to be affected in AD correlate significantly with transverse measurements of pathology such as hippocampal atrophy and amyloid burden. Future work will focus on the chronology of changes (i.e. whether the earliest changes take place in the cortex, in the WM or in sub-cortical structures).

Peter Börnert^1,2, Jan Groen³, Jouke Smink³, and Kay Nehrke^1
1Philips Research, Hamburg, Germany, ²Radiology, LUMC, Leiden, Netherlands, ³Philips Healthcare, Best, Netherlands

Zero echo time (ZTE) imaging allows visualizing short T2-signal components at almost silent scan operation. But due to flip angle limitations the signal is proton density dominated and has poor image contrast. Thus, magnetization preparation is an appropriate approach to manipulate the contrast in ZTE (including: fat suppression, T1-, T2-weighting). A comparison has been made between ZTE, Ultra-short echo time imaging and conventional Cartesian sampling showing similar contrast options and flexibility among those with almost silent operation for ZTE and the advantage of visualizing short T2 components.

Vipul R Sheth¹, Hongda Shao¹, Jun Chen¹, Jody Corey-Bloom², Graeme M Bydder¹, and Jiang Du^1
1Radiology, University of California, San Diego, CA, United States, ²Neurosciences, University of California, San Diego, CA, United States

We evaluated ultrashort echo time sequences for direct imaging and quantitative T2* characterization of purified bovine myelin extract as well as myelin in the white matter of healthy volunteers, cadaveric donor brains with confirmed MS, and in patients with MS.

Vadim Zotev¹, Kymberly D. Young¹, Raquel Phillips¹, Masaya Misaki¹, and Jerzy Bodurka^1,2
1Laureate Institute for Brain Research, Tulsa, OK, United States, ²College of Engineering, University of Oklahoma, Tulsa, OK, United States

We have investigated effects of real-time fMRI neurofeedback (rtfMRI-nf) targeting the left amygdala (LA) to identify changes in LA functional connectivity that correlate with depression severity (HDRS). Thirteen MDD patients learned to upregulate their LA activity using rtfMRI-nf during a positive emotion induction task based on retrieval of happy autobiographical memories. We observed a significant positive correlation between the LA connectivity enhancement across rtfMRI-nf runs and HDRS for several key brain regions including the rostral anterior cingulate cortex (rACC) and mediodorsal thalamus. Our results suggest that rtfMRI-nf holds ability to correct the LA functional connectivity impairments specific to MDD.

Deanne Thompson^1,2, Jian Chen¹, Richard Beare¹, Christopher Adamson¹, Zohra Ahmadzai¹, Claire Kelly¹, Terrie Inder³, Lex Doyle^1,4, Marc Seal¹, and Peter Anderson^1,5
1Murdoch Childrens Research Institute, Parkville, Victoria, Australia, ²Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia,³Brigham and Women's Hospital, Massachusettes, United States, ⁴Royal Women's Hospital, Parkville, Victoria, Australia, ⁵Paediatrics, University of Melbourne, Parkville, Victoria, Australia

We aimed to determine whether adverse perinatal events had a lasting effect on white matter connectivity in childhood, and whether difficulties very preterm children face may be explained by altered connections within the brain. We identified specific brain networks where reduced connectivity was associated with lower gestational age, perinatal infection and brain abnormality at term, as well as with impaired IQ and motor functioning at 7 years of age. This study highlights the importance of prevention or intervention following perinatal insults, and increases our understanding of the neurological mechanisms and brain networks underlying impairments common to very preterm children.

Ying-hui Chou¹, Hui You², Han Wang², Yan-Ping Zhao², Bo Hou², Nan-kuei Chen¹, and Feng Feng^2
1Duke Brain Imaging and Analysis Center, Durham, NC, United States, ²Peking Union Medical College Hospital, Beijing, China

In this study, we demonstrated that 10-session 5-Hz repetitive transcranial magnetic stimulation (rTMS) targeting at the left primary motor area could be used to improve motor function in patients with Multiple System Atrophy (MSA). The improvement of motor function was accompanied by increases in resting-state functional connectivity associated with the default mode network. Our findings shed light on the clinical utility of the rTMS technique, and the identification of rTMS- and symptoms-related functional networks may generate new insights into future therapeutic candidate for patients with MSA.

Mayank V Jog¹, Robert Smith², Kay Jann², Walter Dunn³, Allan Wu², and Danny JJ Wang^2
1Biomedical Engineering, University of California Los Angeles, Los Angeles, California, United States, ²Neurology, University of California Los Angeles, Los Angeles, California, United States, ³Psychiatry, University of California Los Angeles, Los Angeles, California, United States

Transcranial Direct Current Stimulation (tDCS) is a neuromodulation technique that affects cortical excitability. tDCS has been shown to help with depression, stroke and cognition. Simulations have shown that the direct current can penetrate into the brain parenchyma, especially in the vicinity of the electrodes. Based on Ampere’s Law, we used MRI field mapping to visualize the current induced magnetic field changes in 12 healthy participants and observed in-vivo evidence of the effects of tDCS penetrating through to cortical and sub-cortical regions.

Arash Nazeri^1,2, M. Mallar Chakravarty^3,4, David J. Rotenberg¹, Tarek K. Rajji¹, Yogesh Rathi⁵, Oleg V. Michailovich⁶, and Aristotle N. Voineskos^1
1Centre for Addiction and Mental Health, Toronto, ON, Canada, ²Department of Psychiatry, University of Toronto, Toronto, ON, Canada, ³Department of Psychiatry, McGill University, Montreal, QC, Canada, ⁴Cerebral Imaging Centre, Douglas Institute, Verdun, QC, Canada, ⁵Laboratory of Mathematics in Imaging, Harvard Medical School, Boston, MA, United States, ⁶Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, ON, Canada

Post-mortem studies have documented age-related neocortical dendritic deficits, while compensatory dendritic changes appear to take place in other regions. By applying the neurite-orientation dispersion and density imaging (NODDI) model to multi-shell diffusion images, we found an in vivo pattern aligned very closely with the postmortem data indexing neocortical vulnerability and hippocampal compensation. We further demonstrated that these microstructural changes have consequences in cognitive-function, and brain resting-state networks with known age-related susceptibility.

Charles G Cantrell¹, Parmede Vakil¹, Sameer A Ansari², and Timothy J Carroll^1
1Biomedical Engineering, Northwestern University, Chicago, Illinois, United States, ²Radiology, Northwestern University, Chicago, IL, United States

We imaged 23 patients with DCE-MRI and calculated wall permeability parameters using a Tofts model and a point source diffusion model. Both provided statistically significant information about rupture risk. The diffusion model provides more information about wall thickness.

Nikki Dieleman¹, Anja G. van der Kolk¹, Jaco J.M. Zwanenburg^1,2, Manon Brundel³, Anita A. Harteveld¹, Geert Jan Biessels³, Fredy Visser^1,4, Peter R. Luijten¹, and Jeroen Hendrikse^1
1Radiology, University Medical Center Utrecht, Utrecht, Utrecht, Netherlands, ²Image Science Institute, University Medical Center Utrecht, Utrecht, Netherlands, ³Neurology, University Medical Center Utrecht, Utrecht, Netherlands, ⁴Philips, Best, Netherlands

In this prospective study we investigated the presence of cortical microinfarcts (CMIs) at 7.0 tesla MRI in patients with a transient ischemic attack or ischemic stroke of the anterior circulation and explored the relationship between intracranial atherosclerosis (ICAS), CMIs and macroinfarcts. This study shows that in CMIs represent a relevant portion of the total cerebrovascular lesion load and coexist with macroinfarcts. Furthermore, specific ICAS characteristics correlate with a higher cerebrovascular lesion load suggesting that ICAS may be a shared etiology. These results shine new light on the spectrum of parenchymal damage caused by ICAS.

Mohamed Tachrount¹, Andrew Davies², Roshni Desai², Kenneth Smith², David Thomas¹, and Xavier Golay^1
1UCL Institute of Neurology, London, London, United Kingdom, ²Department of Neuroinflammation, UCL Institute of Neurology, London, United Kingdom

For the first time, the feasibility of measuring vasoreactive changes in SCBF to a carbogen challenge in healthy rats was shown. Different areas of the spinal cord show different reactivity with a high degree of reproducibility. These preliminary results highlight the potential of the developed technique in the investigation of the pathogenesis of neuroinflammatory diseases such as Multiple Sclerosis.

Tsang-Wei Tu¹, Rashida A. Williams², Jacob D. Lescher², L. Christine Turtzo², and Joseph A. Frank^2
1Radiology and Imaging Sciences, National Institutes of Health, Bethesda, MD - Maryland, United States, ²Radiology and Imaging Sciences, National Institutes of Health, Maryland, United States

Both DTI and MTR have been shown capable of detecting white matter abnormalities. This study investigates the correlations of DTI and MTR parameters to specific neuropathologies in the time course of rodent weight drop TBI. Comparable to the previous reports, our results suggest that AD and FA are sensitive in reflecting axonal integrity, while RD is able to detect myelin content. The MTR at 20 ppm shows strong correlation with the extent of astrogliosis across TBI time course. Our findings suggest that DTI and MTR are sensitive to multiple neuropathologies, and maybe useful in identifying injury status of mild TBI.

Yolandi van der Merwe^1,2, Leon C. Ho^1,3, Yang Li⁴, Maxine R. Miller^4,5, Chiaki Komatsu⁴, Hongkun Wang⁴, Michael B. Steketee⁵, Seong-Gi Kim^1,6, Joel S. Schuman^2,5, Kia M. Washington^4,5, Kevin C. Chan^1,5, and the WET Consortium^5
1Neuroimaging Laboratory, University of Pittsburgh, Pittsburgh, Pennsylvania, United States, ²Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States, ³Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong, China,⁴Department of Plastic and Reconstructive Surgery, University of Pittsburgh, Pennsylvania, United States, ⁵Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States, ⁶Center for Neuroscience Imaging Research, Institute for Basic Science, Sungkyunkwan University, Suwon, Korea

Whole eye transplantation (WET) provides individuals with irreversible vision loss the opportunity to receive an intact visual system. A viable ocular environment that stimulates adequate blood circulation and reconstructs axonal integrity is essential in the restoration of visual function. The purpose of this study is to demonstrate the viability of our WET model to assess aqueous humor dynamics and tissue permeability of the transplanted eye using gadolinium (Gd)-enhanced MRI. In addition, diffusion tensor imaging was employed to determine the structural integrity of the optic nerve following WET.