Diffusion: Diffusion Applications

Session Topic: Diffusion Applications
Session Sub-Topic: Diffusion: Brain Applications 1
Diffusion
Radiological Qualitative Assessment of IVIM Parameters for Total Variation Penalty Function Approach: A Pilot Study in Osteosarcoma
Amit Mehndiratta1, Esha Badiya Kayal1, Kedar Khare 2, Sameer Bakhshi3, Raju Sharma4, and Devasenathipathy Kandasamy4
1Centre for Biomedical Engineering, Indian Institute of Technology Delhi, New Delhi, India, 2Department of Physics, Indian Institute of Technology Delhi, New Delhi, India, 3Dr. BRA Institute-Rotary Cancer Hospital, All India Institute of Medical Sciences, New Delhi, India, 4Department of RadioDiagnosis, All India Institute of Medical Sciences, New Delhi, India
IVIM imaging is not in clinical use for many years as the parameter estimation has been noisy and had poor diagnostic accuracy. Regularization based IVIM methods has been developed and radiologist rating is evaluated for clinical interpretation and diagnostic accuracy in osteosarcoma.
Figure 1: Percentage of frequency of qualitative scores in 5-point scale (Excellent:5; Good:4; Fair:3; Poor:2 and Uninterpretable:1) for four criteria for qualitative evaluation of IVIM parametric maps evaluated by five IVIM analysis methodologies a) BE, b) BEseg-2, c)BEseg-1, d)BE+TV and e) BE+HPF.
Table 1: Qualitative scores of IVIM parametric maps evaluated by five IVIM analysis methodologies and Friedman test statistics for statistical significance (p<0.05). Scores are in mean± standard deviation.
Utility of DWI with quantitative ADC in diagnosing residual or recurrent HCCs after TACE: A systematic review and meta-analysis
Hai-Feng Liu1 and Wei Xing1
1Department of Radiology, Third Affiliated Hospital of Soochow University, changzhou, China
This meta-analysis was to investigate the accuracy of DWI and ADC value in diagnosing residual or recurrent HCCs after TACE. This study suggested DW have high diagnostic efficacy, and ADC value can be used  to differentiate residual or recurrent HCCs after TACE.
Fig.5 Forest plots of ADC value between residual or recurrent HCCs and necrotic tumors.
Fig.4. Forest plots of ROC for DWI in the detection of residual or recurrent HCCs after TACE.
Impact of processing pipelines on biological findings of large scale multicenter DTI studies
Chung-Man Moon1, Amritha Nayak1,2, M. Okan Irfanoglu1, and Carlo Pierpaoli 1
1National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, United States, 2Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, MD, United States
Some diffusion MRI processing methods introduce significant bias in the results, creating an apparent lack of inter-site harmonization that disappears using other methods. The approach chosen for spatial normalization seem to play a key role in quality of population analysis of DTI results.  
Figure 1. Mean whole-skeleton FA values obtained in the controls of three cohorts with the correction method used in the original ENIGMA processing with eddy_correct, compared with the three methods we tested: recomputed with eddy_correct, eddy, and TORTOISE. P-values were obtained from paired-t test analysis.
Table 1. Age of peak at onset decreased whole-brain FA value on trajectory from the original publication and the TORTOISE DT registration to DT study-specific template in SCZ patients and controls in each cohort.
Rigorous Prospective Reduction of Inter-scanner Variance of Diffusion Imaging: Initial Experience
Vincent Kyu Lee1, Benjamin Meyers1, William T Reynolds2, Rafael Ceschin1, Vincent Schmithorst1, Jeffrey Berman3, Thomas Chenevert4, Borjan Gagoski5, Peter LaViolette6, Deqiang Qiu7, Sudhir Pathak1, Ashok Panigrahy1, and Walter Schneider8
1Radiology, University of Pittsburgh, Pittsburgh, PA, United States, 2Biomedical Informatics, University of Pittsburgh, Pittsburgh, PA, United States, 3Radiology, Children's Hospital of Philadelphia, Philadelphia, PA, United States, 4Radiology, University of Michigan, Ann Arbor, MI, United States, 5Radiology, Harvard Medical School, Boston, MA, United States, 6Radiology, Medical College of Wisconsin, Milwaukee, WI, United States, 7Radiology, Emory University, Atlanta, GA, United States, 8Psychology, University of Pittsburgh, Pittsburgh, PA, United States
Our study showed synthetic phantoms that simulate fiber anatomical characteristics can reduce cross scanner variability and can provide in vitro corrections factors for reducing in-vivo  inter-scanner variance specific to discrete segments of cortical association fiber tracts.
Figure 2. Synthetic phantom correction calculations using FA measurements from DTI imaging of the synthetic phantom unidirectional fiber blocks. The first set of scans (A) were used to determine the scanner specific correction factors which were then applied to the second set of scans.For all scanners (B). After the correction (C), a reduction in cross scanner variability is observed.
Figure 3. Along-tract FA analysis of an individual human phantom across multiple sites. The tracts presented are CC Body (A), right CST (B), Splenium (C), and left SLF (D). Present to varying degrees in all the tracts are regions that are more sensitive to scanner variability (blue arrows) and regions that are more reliably measured (red arrows) regardless of MRI used.
Evaluation of longitudinal changes in white matter structural integrity and grey matter volume in Parkinson’s disease
Maurizio Bergamino1, Elizabeth Keeling1,2, Ryan R Walsh3, and Ashley M Stokes1
1Division of Neuroimaging Research, Barrow Neurological Institute, Phoenix, AZ, United States, 2Neuroscience Department, Arizona State University, Phoenix, AZ, United States, 3The Muhammad Ali Parkinson Center, Barrow Neurological Institute, Phoenix, AZ, United States
Advanced DTI metrics (gFA and FW index) and GM volume may provide insight into longitudinal progression in PD, relative to controls. Longitudinal decreases in gFA and GM volume and increases in FW index in PD were observed.
F-stats from 2x2 ANOVA for gFA and FW metrics. In panel (a) the significant clusters for the main effect of TP are shown (for only gFA). Panels (b) and (c) show the significant clusters for group×TP interaction (FW and gFA, respectively). Table in panel (d) shows the summary of the results.
F-stats from 2x2 ANOVA for VBM analysis. In panel (a) the significant clusters for the main effect of TP are shown, while panel (b) shows the significant clusters for group×TP interaction. Table in panel (c) shows the summary of the results.
Are DKI Measures Relatively More Sensitive In Identifying HIV Infection Related Pathologies Than DTI Measures?
Sameer Vyas1, Teddy Salan2, Paramjeet Singh1, Sulaiman Sheriff2, Mahendra Kumar2, and Varan Govind2
1Postgraduate Institute of Medical Education and Research,, Chandigarh, India, 2University of Miami, Miami, FL, United States
DKI measures are relatively more sensitive in identifying HIV infection related pathologies than DTI measures and kFA may be more sensitive to micro-structural damage.
FA and kFA for ROIs with significant group differences.
MD and MK for ROIs with significant group differences.
Application Study of DWI Radiomics Features with Transurethral Resection on Assessing the Muscular Infiltrating of Bladder Carcinoma
guiqin Liu1, shuaishuai XU1, yongming Dai2, Guangyu WU1, and jianrong XU1
1Radiology, Renji Hospital,Shanghai Jiaotong University School of Medicine, Shanghai, China, 2United Imaing Healthcare, Shanghai, China
Purpose: To investigate the value of radiomics features from diffusion-weighted imaging (DWI) in differentiating muscle-invasive bladder cancer (MIBC) from non-muscle-invasive bladder cancer (NMIBC). Methods: This retrospective study included 218 pathologically-confirmed bladder cancer patients (training set: 131 patients, 86 MIBC; validation set: 87 patients, 55 MIBC) who underwent DWI before biopsy through transurethral resection (TUR) between July 2014 and December 2018. Radiomics models based on DWI for discriminating state of muscle-invasive were built using random forest (RF) and all-relevant (AR) methods on the training set and were tested on validation set. Combination models based on TUR data were also built. Discrimination performances were evaluated with the area under the receiver operating characteristic (ROC) curve (AUC), accuracy, sensitivity, specificity, F1 and F2 scores. Qualitative MRI evaluation based on morphology was performed for comparison. Results: No significant difference was found between RF and AR models. RF model was more sensitive than TUR (0.873 vs 0.655, p=0.019) for discriminating muscle-invasive bladder cancer. When combining RF with TUR, the sensitivity increased to 0.964, significantly higher than TUR (0.655, p<0.001), MRI evaluation (0.764, p=0.006), and the combination of TUR and MRI (0.836, p=0.046). Combining RF and TUR achieved the highest accuracy of 0.897 and F2 score of 0.946. Conclusion: Combining DWI radiomics features with TUR could improve the sensitivity and accuracy in discriminating the presence of muscle invasion in bladder cancer for clinical practice. Multi-center, prospective studies are needed to confirm our results.
Radiomics workflow
Study flowchart
Evaluation of simultaneous multislice acquisition with advanced processing vs. conventional sequence in free-breathing DWI for liver patients
Mihaela Rata1, Katja De Paepe1, Matthew R Orton1, Erica Scurr1, Julie Hughes1, Alto Stemmer2, Marcel Dominik Nickel2, and Dow-Mu Koh1
1Royal Marsden Hospital and Institute of Cancer Research, London, United Kingdom, 2Siemens Healthcare, Erlangen, Germany
The study assessed the image quality of free-breathing DWI acquisitions from 25 patients with liver metastases and compared SMS (with/without advanced processing) DWI with standard bipolar echo planar DWI. The SMS protocol with advanced processing was faster and showed better image quality.
Figure 1: b750 images and ADC maps of liver metastases from two patients from each cohort: a 53-year old woman (top / cohort 1) with colorectal cancer and a 61-year old man with bowel cancer (bottom / cohort 2).Note the increased homogeneity signal across the slice on both b-value and ADC images when using the prototype DWI with advanced options (columns 1 vs. 4). Moreover, the advanced option allows for a better delineation of the liver or blood vessels as seen on the b750 images.
Table 2: Mean scores of the overall image quality for each type of images (b100, b750 and ADC map) and each DWI method as derived from the 25-patient cohort. Highlighted in green are the top scores and in red the lowest scores given by the two radiologists (scoring scale was from 1 to 3).
Fourier analysis of dynamic diffusion changes during cardiac cycle in idiopathic normal pressure hydrocephalus
Yuya Yasuda1, Tosiaki Miyati1, Naoki Ohno1, Mitsuhito Mase2, Ryo Yagawa1, Rika Saito1, Masatomo Uehara1, Harumasa Kasai2, Yuta Shibamoto2, and Satoshi Kobayashi1
1Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan, 2Nagoya City University Hospital, Nagoya, Japan
The Fourier analysis of ADC change in the cardiac cycle in iNPH makes it possible to noninvasively obtain a more detailed information regarding the intracranial state in iNPH.
Figure 2. (a) Mean ADC amplitudes from the first to the seventh harmonic in the frontal white matter in the iNPH and control groups and (b) representative images of the mean ADC amplitude.
Figure 4. (a) ADC amplitudes in each frequency component in the frontal white matter in the iNPH and control groups and (b-d) representative images in each frequency component.
Which frontal white matter pathways mediate executive decline in healthy ageing?
Anoushka Leslie1, Ahmad Beyh1,2, Marco Catani3, Flavio Dell'Acqua3, Ceriesse Gunasinghe4, Henrietta Howells5, Richard Parker6, Andy Simmons1, Michel Thiebaut de Schotten7,8, Steve Williams1, and Mitul Mehta1
1Department of Neuroimaging, King's College London, London, United Kingdom, 2NatBrainLab, King's College London, London, United Kingdom, 3Natbrainlab, Department of Neuroimaging, King's College London, London, United Kingdom, 4Department of Psychological Medicine, King's College London, London, United Kingdom, 5Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Universita degli studi di Milano, Milano, Italy, 6IXICO plc, London, United Kingdom, 7Groupe d’Imagerie Neurofonctionnelle, Institut des Maladies Neurodégénératives-UMR 5293, Universite de Bordeaux, Bordeaux, France, 8Brain Connectivity and Behaviour Laboratory, BCBlab, Sorbonne Universities, Paris, France
This study aimed to identify key frontal white matter tracts thought to influence a decline in executive function with age. Microstructural changes to the left uncinate demonstrated a small to medium indirect effect on age-related decline in planning performance.
Predicted and observed tract - task correlations
Results from exploratory analysis showing relationships between left uncinate HMOA, age and planning performance
Increased non-Gaussian subdiffusion in white matter is associated with increased longitudinal blood pressure exposure in adults at midlife
Carson Ingo1,2, Shawn Kurian3, James Higgins4, Lisanne Jenkins5, Donald Lloyd-Jones6, and Farzaneh Sorond1
1Department of Neurology, Northwestern University, Chicago, IL, United States, 2Department of Physical Therapy and Human Movement Sciences, Northwestern University, Chicago, IL, United States, 3Department of Neurology, Chicago, IL, United States, 4Department of Radiology, Northwestern University, Chicago, IL, United States, 5Department of Psychiatry and Behavioral Sciences, Northwestern University, Chicago, IL, United States, 6Department of Preventative Medicine, Northwestern University, Chicago, IL, United States
The increased presence of non-Gaussian subdiffusive dynamics, possibly reflecting the presence of increased neuronal and glial microstructural heterogeneity, is sensitive increased vascular risk exposure, which was not observed with traditional DTI metrics such as FA.
Figure 1: TBSS partial correlation for α and blood pressure exposure over 30 years for 77 longitudinal CARDIA participants (57.0±3.4 years). Red represents significantly changed voxels where there is a significant negative association between α and blood pressure exposure (r=-0.362, p=0.032). Cool map represents the white matter hyperintensity (WMH) probability map from FLAIR. Statistical analyses were adjusted for age, education, race, smoking history, diabetes, and cholesterol risks as covariates and corrected for multiple comparisons using permutation-based testing.
Table 1: Demographics, characteristics, clinical measures, and risk factors for the year 30 of the CARDIA cohort.
Along-tract correlation analysis of diffusion metrics and white matter lesions in a 70-year old birth cohort
Carole Hélène Sudre1,2, Chiara Maffei3, Josephine Barnes2, David Thomas2, David Cash2, Tom Parker2, Chris Lane2, Marcus Richards2, Hui Zhang2, Sebastien Ourselin1, Jonathan Schott2, Anastasia Yendiki3, and M. Jorge Cardoso1
1King's College London, London, United Kingdom, 2University College London, London, United Kingdom, 3Massachusetts General Hospital, Boston, MA, United States
Diffusion metrics extracted from multishell acquisition correlate strongly with white matter hyperintensities along reconstructed tracts. Changes to the diffusion signal are consistently observable in the direct vicinity of lesions.
Figure 1 Lesion (green) and probability (red) maps of selected (Anterior thalamic radiation and forceps major) reconstructed tracts overlaid on a FLAIR image for the three tractography configurations: using b=700, b=2000 or both.
Figure 2 Example of diffusion metrics Z-Score (left axis) and lesion average probability (right axis) profile along a specific tract for DTI, DKI and NODDI measures. Position 0 indicates the centre of mass of the tract probabilistic map. Pearson correlations are indicated for each plotted metric
Microstructural and structural connectivity alterations in dexmedetomidine-induced loss of consciousness
Timo Roine1,2, Oskari Kantonen3, Jaakko Langsjö3,4, Kimmo Kaskinoro5, Roosa Kallionpää2,5,6, Annalotta Scheinin3,5, Katja Valli2,5,6,7, Timo Laitio5, Antti Revonsuo2,6,7, and Harry Scheinin3,5,8
1Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland, 2Turku Brain and Mind Center, University of Turku, Turku, Finland, 3Turku PET Centre, University of Turku and the Hospital District of Southwest Finland, Turku, Finland, 4Department of Intensive Care, Tampere University Hospital, Tampere, Finland, 5Division of Perioperative Services, Intensive Care and Pain Medicine, Turku University Hospital, University of Turku, Turku, Finland, 6Department of Psychology and Speech-Language Pathology, University of Turku, Turku, Finland, 7Department of Cognitive Neuroscience and Philosophy, School of Bioscience, University of Skövde, Skövde, Sweden, 8Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Turku, Finland
We used diffusion MRI to investigate brain microstructure and structural connectivity in dexmedetomidine-induced loss of consciousness. We found rapid local changes most prominent in the left angular gyrus and its connections by using both methods.
Figure 3. Local alterations in betweenness centrality of the structural brain connectivity networks. Statistical significance is illustrated by the color of the node from white (not significant) via yellow and red to black (most significant) as shown by the color bar. The size of the node reflects the volume of the gray matter area. The color of the edges corresponds to the direction – red: left (L)-right (R), blue: inferior (I)-superior (S), green: anterior (A)-posterior (P) The betweenness centrality of the left angular gyrus was significantly decreased (P=0.00027).
Figure 2. Local microstructural differences in mean diffusivity (A, B, E) and axial diffusivity (C, D). In Fig. 2E the location of the left angular gyrus is highlighted. The color scale from red to yellow describes the statistical significance of the decrease in the microstructural metric in the loss of consciousness (LOC) state compared to awake state. The white matter skeleton is visualized in green. The images are presented in radiological convention (left hemisphere on the right and vice versa).
Session Topic: Diffusion Applications
Session Sub-Topic: Diffusion: Brain Applications 2
Diffusion
Presurgical planning of MRgFUS for Essential Tremor (ET) with protocol for high quality DTI
Amritha Nayak1,2, Angela Bissoli3, Okan M Irfanoglu2, Guiseppe Ricciardi3, Elisa Ciceri3, and Carlo Pierpaoli Pierpaoli2
1Henry Jackson Foundation for advancement in Military Medicine Inc, Rockville, MD, United States, 2National Insitutes of Health, Bethesda, MD, United States, 3Azienda Ospedaliera Universitaria Integrata, Verona, Italy
The role of high quality DTI is clearly highlighted in this preliminary evaluation, to more accurately identify the initial target for sonication in MRgFUS presurgical planning.
Figure2: Top row: coronal view of the acute postsurgical T2WI from four patients where final target has been identified (blue dot), based on the criteria described in figure1. Bottom row: coronal view of the high quality presurgical DTI and the corresponding location of the final target, for each patient.
Figure3: Left column: In patient 3, the location of the first target point of sonification on postsurgical T2WI and its corresponding location on the high quality DTI. The sub threshold initial sonication at this site resulted in patient experiencing slight paresthesia. Right column: The final target location selected for surgery based on the positive functional feedback received from the patient and its corresponding location on the presurgical high quality DTI.
Abnormal insula white matter tracts in smokers
Chao Wang1, Shuyue Wang1, Peiyu Huang1, and Minming Zhang1
1Department of Radiology, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
In this study, we found abnormal white matter tracts of insula subregions in smokers.These altered insula microstructural connectivity could interfere with the normal neural circuitry of reward processing, which might be the underlying neurobiology of nicotine addiction.
Figure 1. Probabilistic tractography of the AI tracts.
Figure 2. The differences of the diffusion findings of insula tracts between smokers and nonsmokers. Compared with nonsmokers, in the left hemisphere, smokers showed lower FA values of PI-NAc and AI-NAc. In the right hemisphere, smokers showed increased FA values of AI-mOFC, PI-mOFC and PI-NAc; decreased AD values of AI-mOFC, PI-mOFC and PI-NAc; decreased RD values of AI-mOFC, PI-mOFC, and PI-NAc; as well as decreased MD values of AI-mOFC, PI-mOFC, and PI-NAc.
Rich-Club Organizational Changes Over the Course of Motor Recovery after First-Time Acute Stroke
Lu Wang1, Hing-Chiu Chang1, Peng Cao1, and Edward.S Hui1
1Department of Diagnostic Radiology, The University of Hong Kong, Hong Kong, China
Rich-club organization remerged one month after stroke and high order regions were found at 6 months when patients functionally recovered, which suggests potential relation between reemergence of rich-club organization and motor recovery.
Figure 1. Rich club coefficient of group-averaged structural brain networks at (A) within 1 week, and (B) 1, (C) 3 and (D) 6 months after first-time ischemic acute stroke. * p < 0.01 after FDR correction, indicating a significant rich-club organization at nodal degree k.
Table 1. Rich-club nodes at different time points after stroke
Tractography based organization of the hyperdirect pathway to the subthalamic area in HCP subjects and parkinsonian patients
Gizem Temiz1, Sophie Sébille1, Chantal François1, Eric Bardinet1, and Carine Karachi1,2
1CENIR, Institut du Cerveau et de la Moelle Epinière, Paris, France, 2AP-HP, Hôpital de la Pitié-Salpêtrière, Department of Neurosurgery, Paris, France, Paris, France
Our aim is to analyze the tractography based sub-parcellisation of subthalamic regions. Motor cluster was located in the posterolateral STN, a limbic cluster located medially in the MSR, and a motor-limbic cluster located in between were observed.
Figure 1: Cortical streamlines for STN and MSR: A. for a HCP subject, and C. for a PD patient. Histograms for HCP dataset (B.) and for PD dataset (D.) showing averaged connectivity of different cortical areas to the STN and MSR. The percentages of mean streamline numbers connecting the different sensorimotor (green), associative (blue) and limbic (red) cortical areas to the STN (dark bars) and to the MSR (bright bars) are shown for the left hemisphere (LH).
Figure 2: 3D localization of the three cortical clusters in both the STN and MSR in native spaces A. for 6 HCP subjects, and B. for 6 PD patients
Differentiating Low- and High-Grade Adult glioma Using Multi-diffusion Models
Junqi Xu1, He Wang1,2, Xueying Zhao1, Hui Zhang1, Xiaoyuan Feng3, and Ren Yan3
1Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China, 2Human Phenome Institute, Fudan University, Shanghai, China, 3Radiology, Huashan Hospital, Fudan University, Shanghai, China
We have developed a multi-model of DWI platform for pathological diagnosis. Herein, FROC, CTRW and DKI performed best among these models in differentiating low- and high-grade adults brain tumor.
Fig. 1 All models of diffusion MR imaging. This image shows one patient with high-grade brain tumor, where the first image is DWI at b = 1500s/mm2and from image a) to p) represents "ADCmap", "Dmap", "Df map", "Dsmap" of IVIM ,"DDCmap","$$$\alpha$$$map" of SEM,"Dmap","$$$\mu$$$map","$$$\beta_f$$$map" of FROC,"Dcmap","$$$\alpha_c$$$map","$$$\beta_c$$$map" of CTRW, "Dk map","Kmap"of DKI and "ADCSmap ” of SM respectively.
Fig. 2 Jointly parameters in each models and this picture shows ROC analysis of 7 models.
Evaluating advanced multi-shell diffusion MRI microstructural biomarkers of Alzheimer’s disease
Julio Ernesto Villalon Reina1, Talia Miriam Nir2, Sophia Thomopoulos2, Lauren E Salminen3, Neda M Jahanshad2, Rutger Fick4, Matteo Frigo5, Rachid Deriche5, and Paul M Thompson2
1USC Imaging Genetics Center, University of Southern California, Los Angeles, CA, United States, 2USC Stevens Neuroimaging and Informatics Institute, University of Southern California, Marina del Rey, CA, United States, 3USC Imaging Genetics Center, University of Southern California, Marina del Rey, CA, United States, 4Therapanacea, Paris, France, 5Athena Project Team, Inria Sophia-Antipolis Méditerranée, Université Côte d'Azur, Nice, France
We found that DTI diffusivity and MC-SMT measures showed the highest prediction accuracy, but differential anatomical distributions of classifying voxels. MC-SMT may offer greater sensitivity and specificity to MCI as MC-SMT resulted in the highest recall and fewest classifying voxels.
Figure 1. Anatomical distribution of logistic regression voxel-wise weights (i.e., odds) that contribute to correct classification, for the four best classifying dMRI measures.
Table 1. Classification accuracy and MCI recall for all tested measures. Recall values are multiples of 10% as there were 10 MCI individuals in the test group. As the training and test group sizes increase, these measures may differ more from one another.
Topological alterations in structural brain connectivity networks are associated with survival after out-of-hospital cardiac arrest
Timo Roine1,2, Oskari Kantonen3, Ulrika Roine1, Sami Virtanen4, Jani Saunavaara4,5, Riitta Parkkola4, Ruut Laitio6, Olli Arola6, Marja Hynninen7, Juha Martola8, Heli M Silvennoinen8, Marjaana Tiainen9, Risto O. Roine10, Harry Scheinin6, and Timo Laitio6
1Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland, 2Turku Brain and Mind Center, University of Turku, Turku, Finland, 3Turku PET Centre, University of Turku and the Hospital District of Southwest Finland, Turku, Finland, 4Department of Radiology, Turku University Hospital, University of Turku, Turku, Finland, 5Department of Medical Physics, Turku University Hospital, University of Turku, Turku, Finland, 6Division of Perioperative Services, Intensive Care and Pain Medicine, Turku University Hospital, University of Turku, Turku, Finland, 7Division of Intensive Care Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland, 8Department of Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland, 9Department of Neurology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland, 10Division of Clinical Neurosciences, Turku University Hospital, University of Turku, Turku, Finland
We investigated structural brain connectivity networks after out-of-hospital cardiac arrest to detect differences related to survival. We found that decreased strength and efficiency were both globally and locally related to increased mortality at 6 months.
Figure 2. Local decreases in A) strength and B) local efficiency of the structural brain connectivity networks in patients who did not survive after OHCA compared to the survivors. The color of the node indicates the statistical significance of the results. The results were adjusted for false discovery rate (FDR) with a significance threshold 0.05. Age, gender, and imaging site were used as covariates in the statistical model.
Figure 1. Global structural brain connectivity network differences between the survivors (group 0) and those who did not survive (group 1) after OHCA. The P-values were adjusted for false discovery rate (FDR). Age, gender, and imaging site were used as covariates in the statistical model.
Diffusion MRI reveals macro- and microstructural changes in cosmonauts' brains after long-duration spaceflight
Steven Jillings1, Angelique Van Ombergen2, Elena Tomilovskaya3, Alena Rumshiskaya4, Liudmila Litvinova4, Inna Nosikova3, Ekaterina Pechenkova5, Ilya Rukavishnikov3, Inessa Kozlovskaya3, Stefan Sunaert6, Paul M Parizel7, Valentin Sinitsyn8, Victor Petrovichev4, Steven Laureys9, Peter zu Eulenburg10, Jan Sijbers11, Floris Wuyts1, and Ben Jeurissen11
1Lab for Equilibrium Investigations and Aerospace, Dept. of Physics, University of Antwerp, Antwerp, Belgium, 2Translations Neuroscience, Dept. of Medicine, University of Antwerp, Antwerp, Belgium, 3Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russian Federation, 4Dept. of Radiology, Federal Center of Treatment and Rehabilitation, Moscow, Russian Federation, 5Laboratory for Cognitive Research, National Research University Higher School of Economics, Moscow, Russian Federation, 6Dept. of Imaging and Pathology, KU Leuven, Leuven, Belgium, 7Dept. of Radiology, Royal Perth Hospital and University of Western Australia, Perth, Australia, 8Faculty of Fundamental Medicine, Lomonosov Moscow State University, Moscow, Russian Federation, 9Coma Science Group, Dept. of Neurology, University (Hospital) of Liège, Liège, Belgium, 10German Center for Vertigo and Balance Disorders, Dept. of Neurology, Ludwig-Maximilians-University Munich, Munich, Germany, 11imec - Vision Lab, Dept. of Physics, University of Antwerp, Antwerp, Belgium
Spaceflight causes a redistribution of CSF and concomitant GM density changes. As opposed to earlier findings, we can strongly conclude that the GM changes are morphological and do not point to atrophy. The net amount of GM and WM increased in sensorimotor areas, indicating neuroplasticity.
Fig 2: CSF and GM density change in the opposite direction at the superior frontal and parietal part of the cerebrum, and along the ventricles and the Sylvian fissure between pre-flight and post-flight. These changes are then largely reversed seven months after spaceflight as revealed by the comparison of follow-up to post-flight. Results are scaled by effect size and are overlayed onto the group template image.
Fig 1: GM mass increases from pre- to post-flight are found in the basal ganglia. WM mass increased from pre- to post-flight in the cerebellum, in a part of the corticospinal tract and in the pre- and postcentral gyri. No significant decreases in GM or WM tissue mass were found between pre- and post-flight. No significant changes were observed between post-flight and follow-up, and between pre-flight and follow-up. Results are scaled by effect size and are overlayed onto the group template image.
High-resolution Distortion-free DWI of Pituitary Adenomas and Rathke Cleft Cysts Using Point-spread-function Encoded EPI
Jieying Zhang1, Chunjie Guo2, Xinrui Liu3, Yishi Wang1,4, Huimao Zhang2, and Hua Guo1
1Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China, 2Department of Radiology, the First Hospital of Jilin University, Changchun, China, 3Department of Neurosurgery, the First Hospital of Jilin University, Changchun, China, 4Philips Healthcare, Beijing, China
PSF-EPI can achieve high-resolution distortion-free DWI in the pituitary, in which two kinds of lesions show different features. PSE-EPI may help with the preoperative differentiation of pituitary lesions without contrast agent.
Figure 1: Images of patient 2 (female, 41-year-old) with an RCC in coronal view. The upper row shows the images of T2-TSE, non-DW PSF-EPI, mean DW PSF-EPI, non-DW SS-EPI and mean DW SS-EPI from left to right. In PSF-EPI, resolution = 1 x 1 x 2 mm3 and b-value = 800 mm/s2 were used. The bottom row shows the same images as those of upper but overlaid with the edges extracted from T2-TSE. Image distortion and signal piling up exist in SS-EPI (red arrow).
Figure 2: Images of patient 1 (female, 36-year-old) with microadenomas (8.3 mm) in coronal (upper) and sagittal view (bottom). From left to Right: T1-TSE, zoom-in T1-TSE, non-DW PSF-EPI, mean DWI(1 x 1 x 2 mm3, b=800 mm/s2) and ADC maps. The lesion shows hypointense in T1-TSE and hyperintense in distortion-free DWI (yellow arrows).
Can mapping cortical diffusivity provide unique microstructural insight into aging?
Graham A. D. Archibald1, Jordan A. Chad1,2, David H. Salat3,4, and J. Jean Chen1,2
1Rotman Research Institute, Baycrest Health Sciences, Toronto, ON, Canada, 2Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada, 3MGH/HST Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States, 4Neuroimaging Research for Veterans Center, VA Boston Healthcare System, Boston, MA, United States
Mean diffusivity (MD), derived from diffusion MRI, serves as a more sensitive measure of aging than thickness across the cortex. MD shows distinct effects than thickness, suggesting that MD provides insight into microscopic degeneration that cannot be detected with macroscopic MRI measures.
Figure 1. Age-related differences in mean diffusivity (MD). MD is significantly correlated with age across the cerebral cortex, particularly in the cingulate, insular and superior temporal cortices.
Figure 2. Age-related differences in cortical thickness (CT). CT is significantly correlated with age across the cerebral cortex, particularly in the motor cortex, although there are less significant regions with age-related differences in CT than there are in MD.
Hemodialysis can contribute to acute changes in cerebral volume and white matter structure
Madeleine T Dacey1,2,3, Stefan E Poirier1,3, Janice Gomes2,4, Udunna C Anazodo1,3, and Christopher W McIntyre1,2
1Medical Biophysics, Western University, London, ON, Canada, 2Kidney Clinical Research Unit, Lawson Health Sciences Center, London, ON, Canada, 3Imaging, Lawson Health Research Insitute, London, ON, Canada, 4Pathology and Laboratory Medicine, Western University, London, ON, Canada
Cognitive impairment and white matter degeneration are common in hemodialysis (HD) patients. To identify the acute effects of HD on the brain, we used a novel system to perform MRI scans during HD. The results indicate ischemia and osmotic imbalances cause acute brain injury.
White and grey matter volume increase significantly at peak stress during hemodialysis while cerebrospinal fluid volume decreases (p<0.05). These changes are consistent with brain swelling and indicate ionic edema.
The colored regions show where each diffusion metric increased significantly (P<0.05) at peak stress during hemodialysis. The blue and yellow regions correspond to fractional anisotropy and axial diffusivity, respectively, and indicate cytotoxic edema. The green and red regions correspond to mean diffusivity. Radial diffusivity is shown in red.
Clinical monitoring of axonal loss in multiple sclerosis using advanced diffusion MRI
Scott Kolbe1, Meaghan Clough1, Frederique Boonstra1, Myrte Strik2, Anneke van der Walt1, Helmut Butzkueven1, Owen White1, Joanne Fielding1, and Meng Law1
1Monash University, Prahran, Australia, 2University of Melbourne, Parkville, Australia
Axonal fibre density measured from clinically acquired diffusion weighted imaging data is seven times more sensitive to longitudinal change compared to brain atrophy.
Figure 1. Top row: Template fibre map showing regions included in analysis. Bottom row: Regions of significant correlation (FWE-corrected p<0.05) between fibre density and brain parenchymal fraction at baseline.
Figure 2. Regions showing significant longitudinal decline in fibre density over time in patients (FWE-corrected p<0.05).
White matter fiber density and cross-section alterations in neuropathic pain after spinal cord injury
Shana Black1,2, Andrew Janson1,2, and Christopher R Butson1,2,3
1Biomedical Engineering, University of Utah, Salt Lake City, UT, United States, 2Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, United States, 3Neurology, Neurosurgery, and Psychiatry, University of Utah, Salt Lake City, UT, United States
Statistically significant (FWE-corrected p<0.1) increases in FC and FDC are evident in a commissural pathway including the splenium and regions of the retrosplenial complex in SCI subjects with chronic neuropathic pain when compared to SCI subjects without any pain symptoms.
Figure 1. White matter fiber cross-section (FC) increases in neuropathic pain. Statistically significant (FWE-corrected) FC increases in SCI subjects with neuropathic pain compared to healthy SCI controls were seen in the posterior splenium of the corpus callosum/retrosplenial complex region. Z values are relative to the AC/PC plane.
Figure 2. White matter fiber density and cross-section (FDC) increases in neuropathic pain. Statistically significant (FWE-corrected p<0.1) FDC increases in SCI subjects with neuropathic pain compared to healthy SCI controls were seen in the posterior splenium of the corpus callosum/ retrosplenial complex region. Z values are relative to the AC/PC plane.
Brain white matter abnormalities and correlation with severity in amyotrophic lateral sclerosis: An atlas-based diffusion tensor imaging study
XiaoQiang Du1, YunJing Xue1, HuaJun Chen1, and ZhongShuai Zhang2
1Fujian Medical University Union Hospital, Fuzhou, China, 2SIEMENS Healthcare, Shanghai, China
We found WM abnormalities extending from the motor to the extra-motor regions in ALS and observed a correlation between distinct diffusion metrics and various clinical variables. In addition, LDH generated the information that could complement conventional DTI metrics.
Fig. 2. The white matter (WM) tracts with significant between-group differences in FA (A), MD (B) and LDH (C), respectively. “R” and “L” indicate right and left side, respectively. RUF, right uncinate fasciculus; RCST, right corticospinal tract; LCST, left corticospinal tract; LCH, left cingulum hippocampus; RSLF, right superior longitudinal fasciculus (temporal part); LATR, left anterior thalamic radiation; RATR, right anterior thalamic radiation; LIFOF, left inferior frontal-occipital fasciculus. These tracts were defined by the JHU ICBMDTI-81 white matter atlas.
Fig. 4. The results of receiver operating characteristic (ROC) curve analysis.
Diffusion Tensor Imaging Detects Cross-Sectional and Longitudinal Brain Changes in Type 2 Diabetes Mellitus
Bhaswati Roy1, Sarah E Choi2, Milena Lai3, Luke Ehlert3, Rashmi Mullur4, Matthew J. Freeby4, and Rajesh Kumar3,5,6,7
1University of California at Los Angeles, LOS ANGELES, CA, United States, 2UCLA School of Nursing, University of California at Los Angeles, Los Angeles, CA, United States, 3Anesthesiology, University of California at Los Angeles, Los Angeles, CA, United States, 4Medicine, University of California at Los Angeles, Los Angeles, CA, United States, 5Radiology, University of California at Los Angeles, Los Angeles, CA, United States, 6Bioengineering, University of California at Los Angeles, Los Angeles, CA, United States, 7Brain Research Institute, University of California at Los Angeles, Los Angeles, CA, United States
Patients with Type 2 diabetes mellitus (T2DM) show brain tissue changes, but the nature and extent of damage and their progression with time are unclear. Using DTI based MD procedures, we showed chronic tissue changes in T2DM subjects and their continued progression after 6 months follow-up.
Figure 1: Brain regions with increased MD values in T2DM patients at baseline and 6 months follow-up appeared over controls. These sites included the (arrows) anterior and posterior cingulate (a-c), frontal (d) and prefrontal (e), insular cortices (f), and cerebellum (g). Few regions emerged with widespread damage in follow-up over baseline T2DM patients, and these sites (ellipses) included the caudate (h), middle cingulate (i), hypothalamus (j), and hippocampus (k). All images are in neurological convention (L = left; R = right). Color bar indicates t-statistic values.
Figure 2: Paired t-test exhibit higher MD values in 6-months follow-up T2DM patients over baseline. The regions with increased MD values included the cerebellum (a), mid (b) and posterior (d) cingulate, thalamus (c, e), insular cortices (f, j), caudate (g), amygdala (h), and hippocampus (i). Figure conventions are same as in Figure 1.
Preliminary Assessment of Intravoxel Incoherent Motion Diffusion-Weighted MRI (IVIM-DWI) Metrics in Alzheimer’s Disease
Maurizio Bergamino1, Ashley Nespodzany1, Leslie C Baxter1,2, Anna Burke3, Richard Caselli2, Marwan N Sabbagh4, Ryan R Walsh5, and Ashley M Stokes1
1Division of Neuroimaging Research, Barrow Neurological Institute, Phoenix, AZ, United States, 2Mayo Clinic Arizona, Phoenix, AZ, United States, 3Department of Neuropsychiatry, Barrow Neurological Institute, Phoenix, AZ, United States, 4Lou Ruvo Center for Brain Health, Cleveland Clinic, Las Vegas, NV, United States, 5The Muhammad Ali Parkinson Center, Barrow Neurological Institute, Phoenix, AZ, United States
IVIM-DWI was used to investigate early AD-related microstructural and functional changes. Significant differences were observed using IVIM biomarkers between healthy controls, MCI, and AD groups, while VBM showed differences only in later AD stages.
Voxel-based analysis for the F-statistics across groups for all analysis methods. VBM results are also shown uncorrected for family-wise error (FWE) in panel (a). For all other panels, we report clusters at a significance threshold of p-value < 0.05 corrected for FWE.
Voxel-based correlations between MoCA/Clock Draw/FAST and VBM/ADC/IVIM metrics. The plots, with the relative mean of R2, represent the correlations of the average values inside the significant clusters.
Session Topic: Diffusion Applications
Session Sub-Topic: Diffusion: Brain Applications 3
Diffusion
A comparison of RESOLVE DWI with delayed gadolinium-enhanced T1-weighted MRI in detecting cholesteatoma based on 531 patients’ data
Yaru Sheng1, Yan Sha1, Rujian Hong1, Zhongshuai Zhang2, and Wenhu Huang1
1Radiology, EENT Hospital of Fudan University, Shanghai, China, 2Siemens Healthcare, Shanghai, China
The comparison between readout-segmented echo-planar imaging (RESOLVE) DWI and delayed gadolinium-enhanced T1-weighted MRI diagnosis of 531 patients with cholesteatoma shows that DWI is a good tool for detecting cholesteatoma.
Figure 1. The ADC distribution of cholesteatoma and non-cholesteatoma. The mean ADC values of these two sets of statistical measurements are: cholesteatoma: 860.77×10-6 mm2/s and non-cholesteatoma: 1529.78×10-6 mm2/s (Wilcoxon rank-sum test, p<0.01).
Figure 2. The area under the ROC curve of the mean ADC value is 0.98, which indicates that the ADC values have very good predictive ability for the detection and differentiation of cholesteatoma and non-cholesteatoma (granulation tissue or cholesterol granulation).
A novel diffusion registration method with the NTU-DSI-122 template to transform free water signal fraction maps to stereotaxic space.
Benjamin T Newman1,2, Ana Untaroiu1, and T. Jason Druzgal1,2
1Department of Radiology & Medical Imaging, Division of Neuroradiology, University of Virginia Health System, University of Virginia, Charlottesville, VA, United States, 2Brain Institute, University of Virginia, Charlottesville, VA, United States
We propose the use of the NTU-DSI-122 template as a flexible, diffusion specific, means of registering subjects to stereotaxic MNI-space by fiber orientation distribution-based registration. We demonstrate it is more consistent than a leading intensity-based registration algorithm. 
Study workflow illustrating the process of moving from native space images (three images on left), registering with the respective template for each method, applying the transform generated from that registration to the free water signal fraction map, and obtaining the free water signal fraction maps in stereotaxic MNI space (two images on right). This process was repeated 5 independent times for each of the 5 subjects.
The mean squared difference between each of the 5 independent registration attempts for each of the 5 subjects involved in analysis are presented, alongside the group mean (±SE). Grey bars represent the SyN intensity-based registration implemented in ANTs and yellow bars represent the WM-FOD based registration implemented in MRtrix.
Diffusion-Ordered NMR Spectroscopy Reconstruction Based on Low-rank and Sparse Inverse Laplace Transform
Enping Lin1, Yu Yang1, Yuqing Huang1, and Zhong Chen1
1Department of Electronic Science, Xiamen University, Xiamen, China
We point out that desired DOSY data should have joint properties of low-rank and sparsity, based on which the optimization model is proposed to attain high-resolution DOSY reconstruction.
Figure 1 The data proccessing flow diagram of DOSY
Figure 2. Reconstructed spectrum for experimental data QGC consisting of quinine (100MmM/L), geraniol (100mMMm/L), camphene (200 mMMm/L) dissolved in deuterated methanol (a) mono-exponential fitting, (b) SILT, and (c) our method named LRSpILT. Areas marked by red rectangular are with overlapping peaks. Artefacts in (b) and (c) are marked with black arrow. Highlighted areas are projected onto the diffusion coefficient dimension, and shown in Figure 4. The center diffusion coefficient values of components are marked with dashed lines.
Diffusion MRI revealed mild optic nerve fiber degeneration during Chimpanzee aging
Chun-Xia Li1, Yumei Yan1, Longchuan Li2, Todd Preuss3, James G Herndon3, Xiaoping Hu4, and Xiaodong Zhang1,3
1Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, United States, 2Department of Pediatric, Emory University School of Medicine, Atlanta, GA, United States, 3Division of Neuroscience and Neurological diseases, Emory University, Atlanta, GA, United States, 4Department of bioengineering, University of California, Riverside, Riverside, CA, United States
Mean diffusivity (MD), axial diffusivity (AD or λll), radial diffusivity (RD or λτ) and fractional anisotropy (FA) showed mild and proportional changes from youth to elder adulthood in elder chimpanzees, significant increase of MD and RD were seen as well. The changes are much milder than that seen in monkey and human brain.
Fig 2 Demonstration of progressive changes of DTI indices (FA, MD, AD, RD) in chimpanzee optic nerves.
Fig 3. progressive evolution of DTI indices of the optic nerve in chimpanzees with the ages of 13-20(n=13), 22-38(n=10), and 40-56 (n=7) years old. *, p<0.07; #, p<0.1, compared 22-38y group by using one-way ANOVA. Error bar: standard deviation
Diffusion Tractography at 0.5T: Comparison to 1.5T
Jeff A Stainsby1, Chad T Harris1, Andrew T Curtis1, Philip J Beatty1, and Curtis N Wiens1
1Synaptive Medical, Toronto, ON, Canada
We demonstrate the feasibility of diffusion tractography from a 0.5T system and compare results qualitatively to tractography obtained from a clinical 1.5T scanner and quantitatively to literature values.
Figure 2: (a) Representative whole brain tractography demonstrated in 3 orthogonal imaging planes and whole brain automatic white matter segmentation results from volunteer #1 obtained at 0.5T (top) and 1.5T (bottom). (b) Analogous tractography images obtained from volunteer #2.
Figure 1: (a) Representative processed FA (left), ADC (middle), and RGB (right) images from volunteer #1 obtained at 0.5T (top) and 1.5T (bottom). (b) Analogous images from volunteer #2.
Diffusion-weighted imaging at ultra-low field MR for acute stroke detection: what can we see?
Tiago Timoteo Fernandes1, Marc Golub1, Andreia Freitas1, Sairam Geethanath2,3, and Rita Gouveia Nunes1
1ISR, IST - University of Lisbon, Lisbon, Portugal, 2Medical Imaging Research Centre, Dayananda Sagar Institutions, Bangalore, India, 3Magnetic Resonance Research Center, Columbia University, NY, DC, United States
Diffusion-weighted Imaging (DWI) can detect ischemic tissue in stroke patients. Ultra-low field systems (ULF) could provide a point-of-care solution but suffer from low SNR. This simulation work investigates the feasibility of DWI at ULF.
Figure 4 - Noise free simulations for two different sequences and their reconstructed images. a) Sample with four different tissues each with their respective relaxation times. The LS tissue (in white) has similar values to the WM. b) Partial EPI sequence in clinical MR scheme with b=1000 s/mm2, B0=1.5T, sm=200T/m/s, gm=30mT/m, res=2mm. c) Spiral Sequence, single shot in LF with b=700 s/mm2, B0=0.2T, sm=50T/m/s, gm =14mT/m, res=3mm. Images were reconstructed for both sequence with no DW (left), with DW (same color bar than no DW) (center) and ADC maps (right).
Figure 2 - SNR and CNR for varying B0 field intensity, gm, spatial resolution (displayed using a logarithmic scale) and b-values. a) Variation of SNR across gm values and B0 field, for a fixed res = 4mm. b) Variation of SNR across resolution values and B0 field, for a fixed gm = 20 mT/m. c) Variation of CNR across resolution values and B0 field, for a fixed gm = 20 mT/m. d) Variation of CNR across b-values, for a fixed gm = 20 mT/m and res = 4mm.
Ultra-high b-value Diffusion MRI for Evaluation of Single Amyloid Precursor Protein Knock-in Mouse Model of Alzheimer’s Disease
Jin Gao1,2, Zachery Morrissey3, Alex Leow3, Orly Lazarov4, Danilo Erricolo1, Richard Magin5, and Weiguo Li2,5
1Electrical and Computer Engineering, University of Illinois at Chicago, Chicago, IL, United States, 2Research Resources Center, University of Illinois at Chicago, Chicago, IL, United States, 3Department of Psychiatry, University of Illinois at Chicago, Chicago, IL, United States, 4Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, United States, 5Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States
Diffusion MRI offers unique insights into the pathophysiology of AD in vivo. This feasibility study aims to assess and visualize the white matter changes using an ultrahigh b-value diffusion MRI.
Fig. 3. Parameters maps generated from CTRW diffusion model for two image slices of an APP knock-in mouse and corresponding slices in WT control. A. α map with arrow pointed to CC; B, D maps (mm2/s) with arrow pointed to AC (upper panel) and CC (lower panel).
Fig. 4. Hippocampus showing lower values in α maps (lower panel) in APP knock-in mouse comparing to the WT control. Upper panel: diffusion-weighted images with b = 4050 s/mm2, with gray bar showing the normalized signal intensity. Lower panel: α maps with color bar showing the extracted α values. Arrow points to the hippocampus.
Cerebrospinal fluid pulsation does not affect on DWI-based thermometry: healthy volunteer study
Koji Sakai1, Jun Tazoe1, Kentaro Akazawa1, Hiroyasu Ikeno2, Toshiaki Nakagawa2, and Kei Yamada1
1Kyoto Prefectural University of Medicine, Kyoto, Japan, 2Kyoto Prefectural University of Medicine Hospital, Kyoto, Japan
As a result of comparison with MRS based temperature, the CSF pulsation into the lateral ventricle during measurement of DWI does not significantly affect the measurement of DWI thermometry.
ΔT along the CSF flow speed at cerebral aqueduct.
Bland-Altman plot between MRS and DWI based temperature.
T2w-FLAIR generation through deep-learning using distortion-free PSF-EPI DWI
Zhangxuan Hu1, Zhe Zhang2, Yishi Wang3, Yajing Zhang4, and Hua Guo1
1Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China, 2China National Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China, 3Philips Healthcare, Beijing, China, 4MR Clinical Science, Philips Healthcare (Suzhou), Suzhou, China
Point-spread-function (PSF) encoded EPI (PSF-EPI) DWI and T2-weighted images were used to generate T2w-FLAIR images by taking the advantages of high-resolution and distortion-free of PSF-EPI. This method has the potential to improve the acquisition efficiency of MRI.
Fig. 3 Generated T2w-FLAIR images using the proposed method with or without PSF-DWI (denoted by CGAN and CGAN w/o DWI, respectively) and their counterpart of the acquired T2w-FLAIR. SSIM values between the generated and acquired T2w-FLAIR were shown on each image. The input T2W-TSE, b = 0 s/mm2 and mean DWI images acquired by PSF-EPI were also provided.
Fig. 2 Network architecture of the generator and the discriminator. Generator: a 2D U-net was designed with 19 convolutional layers (kernel size =3×3), 4 convolutional layers with strides for downsampling (kernel size = 2×2, strides = 2×1), 4 deconvolutional layers with strides for upsampling (kernel size = 2×2, strides = 2×2), and 4 feature contracting paths. Discriminator: 4 convolutional layers (kernel size =3×3) and 4 convolutional layers with strides for downsampling (kernel size = 3×3, strides = 2×2). Batch-normalization (BN) and ReLU were used for each layer.
AMURA with standard single-shell acquisition can detect changes beyond the Diffusion Tensor: a migraine clinical study
Álvaro Planchuelo-Gómez1, Rodrigo de Luis-García1, Antonio Tristán-Vega1, David García-Azorín2, Ángel Luis Guerrero2, and Santiago Aja-Fernández1
1Imaging Processing Laboratory, Universidad de Valladolid, Valladolid, Spain, 2Headache Unit, Hospital Clínico Universitario de Valladolid, Valladolid, Spain
Advanced diffusion measures calculated with AMURA detect changes in migraine patients compared to controls that are not detected by traditional DTI measures. AMURA can give complementary information to DTI-based studies even with low b­-values.
Figure 4. Summary of the results obtained in the diverse analyses. Significant differences between episodic migraine (EM) and controls were found only with the AMURA return-to-origin probability (RTOP), detecting white matter alterations non-measurable with Diffusion Tensor Imaging (DTI). Differences between chronic migraine (CM) and EM were found with return-to-plane probability (RTPP) obtained with AMURA and axial diffusivity (AD) from DTI. No differences were found between CM and controls.
Figure 5. Visual comparison of Diffusion Tensor Imaging (DTI) and Apparent Measures Using Reduced Acquisitions (AMURA). The first row contains the DTI measures, from left to right: axial (AD), mean (MD) and radial diffusivity (RD). The second row contains AMURA metrics, from left to right: return-to-plane (RTPP), return-to-origin (RTOP) and return-to-axis probability (RTAP).
Fewer number of gradient directions in diffusion MRI can be counterbalanced with higher sample size: a migraine clinical study
Álvaro Planchuelo-Gómez1, Santiago Aja-Fernández1, David García-Azorín2, Ángel Luis Guerrero2, and Rodrigo de Luis-García1
1Imaging Processing Laboratory, Universidad de Valladolid, Valladolid, Spain, 2Headache Unit, Hospital Clínico Universitario de Valladolid, Valladolid, Spain
Diffusion MRI scalar measures are more precise employing 61 gradient directions in comparison to 40 and 21 directions. Equivalent results to the 61 gradient directions case can be obtained with 40 and 21 directions by increasing the sample size.
Figure 2. Evolution in the number of regions with significant differences using 61, 40 and 21 diffusion gradient directions. Axial diffusivity was compared between chronic and episodic migraine patients. A decrease in the number of gradients can be compensated by increasing sample size. Number of subjects per group for the diverse iterations is shown in the horizontal axis, corresponding the maximum value to the original sample. Median values are used as punctual estimations. Red, blue and orange represent the number of regions using 61, 40 and 21 gradient directions respectively.
Figure 1. Visual comparison of the results with the diverse diffusion encoding schemes. Results with the original sample comparing axial diffusivity between chronic and episodic migraine patients are shown. The first column contains the results for 61 gradient directions (37 regions with significant differences), and the second and third for 40 (27 regions) and 21 directions (20 regions) respectively. White matter skeleton is shown in blue and voxels with significant differences in red-yellow. The color bar shows the 1-p values (family-wise error corrected).
A DTI Comparative study – Is demyelination in AD resembling primary demyelinating disease (MS) or secondary demyelinating disease (NPSLE)?
Huiqin Zhang1, Hui Zhang1, Franki Kai-Hei Tse 2, Edward Sai-Kam Hui1, Peng Cao1, Kannie Wai Yan Chan3, Queenie Chan4, Karl HERRUP5, and Henry Ka Fung Mak1
1Department of Diagnostic Radiology, The University of Hong Kong, Hong Kong, Hong Kong, 2Department of Health Technology and Informatics, The Hong Kong Polytechnic University, Hong Kong, Hong Kong, 3Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, Hong Kong, 4Philips Healthcare, Hong Kong, Hong Kong, 5Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, United States
AD appears to have similar microstructural WM changes as RRMS, which might indicate that they share similar pathogenetic mechanisms such as demyelination.
Fig 1a. TBSS results of FA, MD, AxD and RD images between normal controls and AD patients. Green represents mean FA skeleton of all participants; yellow-red, red, copper, and blue represent regions with decreased FA (1st row), increased MD (2nd row), increased AD (3rd row) and increased RD (4th row) separately in AD patients (P < 0.05, TFCE corrected for multiple comparisons)
Fig 1b. TBSS results of FA, MD, AxD and RD images between normal controls and MS patients. Green represents mean FA skeleton of all participants; yellow-red, red, copper, and blue represent regions with decreased FA (1st row), increased MD (2nd row), increased AD (3rd row) and increased RD (4th row) separately in MS patients (P < 0.05, TFCE corrected for multiple comparisons).
A longitudinal study on heterogeneity of diffusional parameters of spontaneously-hypertensive rats.
Jung-Sen Hsiao1, Hung-Yu Fu1, Pei-Lun Yu1, Sheng-Min Huang1, Kung-Chu Ho2, and Fu-Nien Wang1
1Biomedical Engineering and Envionmental Sciences, National Tsing-Hua University, Hsinchu City, Taiwan, 2Chang-Gung Memorial Hospital, Taoyuan City, Taiwan
Six spontaneously-hypertensive rats in different ages were scanned on a 7T small animal MR scanner to investigate the diffusional heterogeneity in gray matter by DKI. The diffusional heterogeneity is anticipated as a potential image-based biomarker for evaluating tissue integrity.
Table 1. Tissue characterization ability between mean value and CV by DKI. The number represents the total numbers in eight maps calculated from diffusivities and kurtosis, derived from DKI.
Figure 2. Diffusional heterogeneities of DKI were tested for the tissue characterization.
In vivo Diffusion Tensor Magnetic Resonance Imaging of  Chronic Cocaine Administered Mouse Brain
Ethan A Cook1, Shannon E Callen2, Shilpa Buch2, and Balasrinivasa R Sajja3
1College of Medicine, University of Nebraska Medical Center, Omaha, NE, United States, 2Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, United States, 3Radiology, University of Nebraska Medical Center, Omaha, NE, United States
In vivo DTI detected brain structural changes in cocaine administered mice. Our findings indicated demyelination in white matter structures in chronic administration in mice. Results also indicated the involvement of gray matter. 
Figure 3: Change in DT measures at different time points. Blue, green, and orange colors denote values at week 0, week 1, and week 4 respectively. Statistically significant change is represented by symbol as ●: (W0~W1), ◆: (W1~W4), *: (W0~W4).
Figure 1: Representative FA, MD, AD, and RD maps from same cross-section of a mouse brain.
Brain microstructural alterations of left precuneus mediate the association between KIBRA rs17070145 and working memory in healthy adults.
Junxia Wang1, Sichu Wu2, Jilei Zhang3, and Bing Zhang2
1Nanjing Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China, 2Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China, 3Clinical Science, Philips Healthcare, Shanghai, Shanghai, China
KIBRA C-allele carriers had increased AD, RD, MD and decreased FA, MK, RK, ALFF compared with KIBRA TT homozygotes. The MK, RK of the left precuneus mediated the association between the KIBRA polymorphism and the working memory performance. 
Figure 3 Mediation analysis for the associations among KIBRA, MK, RK, ALFF in the left precuneus and working memory.
Figure 1 Comparison of diffusion and kurtosis metrics between KIBRA C and TT groups.
Session Topic: Diffusion Applications
Session Sub-Topic: Diffusion: Applications Beyond the Brain
Diffusion
A Longitudinal Study on Assessing the Recovery of Spinal Cord on Incomplete Traumatic Spinal Cord Injury using Diffusion Tensor Imaging
Bing Yao1,2, Hannah Ovadia1, Gail Forrest3, and Steven Kirshblum2,4
1Rocco Ortenzio Neuroimaging Center, Kessler Foundation, West Orange, NJ, United States, 2Department of Physical Medicine and Rehabilitation, Rutgers University, Newark, NJ, United States, 3Center for Mobility and Rehabilitation Engineering Research, Kessler Foundation, West Orange, NJ, United States, 4Kessler Institute for Rehabilitation, West Orange, NJ, United States
Our study demonstrates that DTI may serve as a tool to assess the changes at different regions of the spine on spinal cord injured patients during their six months recovery period after injury, of which information is usually hard to be obtained by traditional evaluation methods.
Fig. 1: Comparison of the spine MR images and tractography for a SCI patient (B) and a matched healthy control (A). The red circle indicates a significant signal dropout at the C4 level, which matches the location of the implanted hardware in this SCI patient.
Fig. 3: Above Injury Level. Mean values of AD, FA, MD, and RD above the area of injury across five visits. Values represent mean ± SEM. There were significant differences in AD and FA between groups, indicating by “*” (p < 0.05).
Quantitative assessment of thyroid and parathyroid lesions by using ZOOMit-based IVIM, DKI and DWI
Bing Liu1,2, Xiangtao Lin1,2, Peng Zhao1, Xianshun Yuan1,2, Mengxiao Liu3, Xiang Feng4, Lei Xue5, Mimi Tian2, Shuai Zhang1,2, Dejuan Shan1,2, and Xiaoli Li1,2
1Department of Radiology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China, 2Shandong University, Jinan, China, 3MR Scientific Marketing, Diagnostic Imaging, Siemens Healthcare Ltd, Shanghai, China, 4MR Scientific Marketing, Diagnostic Imaging, Siemens Healthcare Ltd, Beijing, China, 5MR Application, Siemens Healthcare Ltd, Jinan, China
D* in IVIM, MK in DKI and ADC in DWI were superior than other diffusion parameters (D, F in IVIM, MD in DKI) in accurately locating lesions as well as differentiating between lesions and normal thyroid parenchyma.
Figure 1: Images of a 65-year-old woman with a parathyroid adenoma (green circles and white arrowheads). The mean values of IVIM-D, IVIM-F, IVIM-D*, DKI-MK, DKI-MD and ADC of the ROIs (green circles) in the lesion were 0.70×10-3mm2/s, 16.3%, 9.81×10-3mm2/s, 1.60, 1.62×10-3mm2/s and 0.95×10-3mm2/s. Signal intensity of the lesion (arrowheads) decayed with b-values going up from 0 to 2000 s/mm2.
Figure 2: A 72-year-old man with malignant nodule on left thyroid lobe. a-c: fat-suppressed T2-weighted images of the lesion (arrowheads) at the position of axial, coronal and sagittal. d-f: ROIs (green circle) of the lesion shown on IVIM parametric maps (d: D map, e: F map and f: D* map). g-i: DKI parametric maps (g: MK map and h: MD map) and ADC map (i) of the lesion (asterisks). The mean values of D, F, D*, MK, MD and ADC of the malignant lesion were 0.89×10-3mm2/s, 26.20%, 7.05×10-3mm2/s, 0.87, 2.08×10-3mm2/s and 1.19×10-3mm2/s, respectively.
Quantitative evaluation of IVIM-DWI combined with simplified DKI for subtype diagnosis and grading prediction in retroperitoneal liposarcoma
Zhang Jiulong1, Shi Nannan1, Zhang Yijun1, Ye Wen1, Zhang yong2, Shan fei1, and Shi Yuxin1
1radiology department, Shanghai public health clinical center, shanghai, China, 2General surgery, Shanghai public health clinical center, shanghai, China

The quantitative parameters of IVIM-DWI combined with sDKI models are helpful to improve the accuracy and specificity in differential diagnosis of RPLS subtypes and have the potentiality to predict the histological grading of RPLS.

 

Fig.1. Column bar graph (Mean with SD) of the parameters (f, D*, D, Dapp, Kapp and ADC) of IVIM-DWI and sDKI models in psoas group, retroperitoneal liposarcoma (RPLS) and its subgroups (well-differentiated liposarcoma (WDLS), dedifferentiated liposarcoma (DDLS), myxoid liposarcoma (MLS)), which were analyzed by LSD test. (ns p>0.05, * p<0.05, ** p<0.01, *** p<0.001)
A 34-year-old woman with a large retroperitoneal soft tissue mass. mDXION-water phase showed iso-signal or low signal, while T2WI/SPAIR image showed high signal. There were more mucous components in the lesion, and the solid components were obviously enhanced after enhancement, while the mucous area showed uneven flocculent enhancement. IVIM-DWI and sDKI parameter maps: mean f value=62%, mean D value=2.02 mm2/sec×10-3, mean Kapp value=0.33. Postoperative pathology confirmed MLS.
Is ADC Measurement of Parotid Gland Tumor Sufficient using the Largest Slice rather than Whole Tumor
Shao-Chieh Lin1, Jui-Heng Lin1, Chun-Jung Juan2,3,4, Kai-Min Chien5, Teng-Yi Huang6, Yi-Jui Liu7, Chang Hsien Liu 5, Ya-Hui Li5, Szu Hsien Chou 5, and Chi-Feng Hsieh5
1Master 's Program of Biomedical Informatics and Biomedical Engineering, Feng Chia University, Taichung, Taiwan, 2Department of Medical Imaging, China Medical University Hsinchu Hospital, Hsinchu, Taiwan, 3Department of Radiology, School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan, 4Department of Computer Science and Information Engineering, National Taiwan University, Taipei, Taiwan, 5Department of Medical Imaging, Chinese Medical University Hsinchu Hospital, Hsinchu, Taiwan, 6Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan, 7Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan
ADC measurement in the slice with the largest tumor which tumor size over one third of the total tumor volume, could instead the ADC measurement of whole tumor for diagnosis of the PMA, WT and MT in parotid gland.
Figure 1. Illustration of manual contouring of a parotid tumor (blue) on EP-DWI (b0) for further calculating the mean and standard derivation on ADC map.
Figure 2. ADC of parotid gland tumors of PMA, WT and MT on the largest slice and whole tumor. PMA: pleomorphic adenoma; WT: Warthin’s tumor; *** represents a P <0.001.
Intravoxel incoherent motion and diffusion kurtosis imaging in the assessment of pathological grades of clear cell renal cell carcinoma
Qing Xu1, Weiqiang Dou2, and Jing Ye1
1Department of Radiology, Clinical Medical School of Yangzhou University, Northern Jiangsu People’s Hospital, Yangzhou, 457, China, 2GE Healthcare, MR Research China, Beijing, China
IVIM-related parameters (ADC, apparent diffusion coefficient; D, true diffusivity) and DKI-related parameters (MD, mean diffusivity; MK, mean kurtosis) were able to significantly distinguish between low- and high-grade clear cell renal cell carcinoma. 
A 65-year-old woman with pathologically confirmed epithelioid angiomyolipoma in the left kidney. The lesion showed low signal intensity (SI) on T2-weighted image (a). (b-g) Corresponding parametric maps(ADC, D, D*,f, MD, MK). Tumor values (white arrow) were 0.51×10−3 mm2/s, 1.04×10−3 mm2/s, 57.8×10−3 mm2/s, 0.24, 1.67, 0.77, respectively. (h) pathological analysis displayed changes indicating ccRCC (Fuhrman II) (hematoxylin and eosin, ×200).
A 66-year-old man with pathologically confirmed clear cell renal cell carcinoma in the right kidney. The lesion showed very low signal intensity (SI) on T2-weighted image (a). (b-g) Corresponding parametric maps (ADC, D, D*,f, MD, MK). Tumor values (white arrow) were 0.32×10−3 mm2/s, 0.92×10−3 mm2/s, 10.09×10−3 mm2/s, 0.43, 1.05, 1.01, respectively. (h) pathological analysis confirmed ccRCC (Fuhrman IV) (hematoxylin and eosin, ×200).
Investigating multi-compartment diffusion MRI models in the cervical spinal cord of multiple sclerosis patients
Kurt G Schilling1, Kristin P O'Grady1,2, Samantha By3, Haley Feiler1, Francesca Bagnato4, Bennett A Landman1,5,6,7, and Seth A Smith1,5,8
1Vanderbilt University Institute of Imaging Science, Nashville, TN, United States, 2Radiology and Radiological Sciences, Vanderbilt University Medial Center, Nashvillet, TN, United States, 3Hyperfine Research Inc, Guilford, CT, United States, 4Neurology, Vanderbilt University Medical Center, Nashville, TN, United States, 5Biomedical Engineering, Vanderbilt University, Nashville, TN, United States, 6Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States, 7Electrical Engineering, Vanderbilt University, Nashville, TN, United States, 8Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, United States
We investigate multi-compartment diffusion MRI models in the in vivo spinal cord of MS patients. We find differences in diffusion measures between patients and controls, and characterize relationships of indices with clinical disability measures.
Figure 1. Qualitative differences are apparent in multi-compartment indices between controls (N=21) and MS patients (N=12). Indices are registered to template space and averaged. For DTI (top), NODDI (middle), and SMT (bottom), indices for control and MS are displayed on the same scale.
Figure 3. Multi-compartment indices derived from DTI (top), NODDI (middle), and SMT (bottom) are plotted against EDSS score for all MS patients (Note that 10 of the 12 MS patients had clinical EDSS scores). Lines of best fit are shown over the whole cord (black), and in WM (red) and GM (blue) regions. No correlations were statistically significant – although clear (nonlinear) trends are apparent in many indices.
Radiomics Analysis of Apparent Diffusion Coefficient Maps with Various b-value Combinations for Differentiation of Prostate Cancer
Eo-Jin Hwang 1 and Moon Hyung Choi2
1Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea, 2Eunpyeong St.Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
The aim of this study was to differentiate prostate cancer from benign tissues using radiomics in ADC maps that were produced by various combinations of b-values. The ADC radiomics features with LASSO regularization effectively discriminated prostate cancer from the benign tissues.
Figure1. Representative slices of the axial, apparent diffusion coefficient (ADC) maps generated by different combinations of b-values: (a) 0 and 1000s/mm2 (ADC1), (b) 100 and 1000s/mm2 (ADC2) and (c) 100 and 1500s/mm2 (ADC3). For each map, the location of the cancer region is identified with an orange arrow.
Figure2. (a) A mean squared error plot as a function of the log of a LASSO regularization parameter λ for ADC2. The dotted lines illustrate each fold, and the solid line represents the average across 5 fold cross validation. The lambda with the minimum mean squared error was chosen as the final regularization parameter (vertical line). (b) LASSO coefficient profiles of the radiomics features for ADC2. A coefficient plot was produced against the log of lambda sequence. A vertical line was drawn at the log of lambda chosen in (a), where optimal λ resulted in 4 nonzero coefficients.
Two-step approach in IVIM parameter quantification
Xin Li1, Ryan Kopp2,3, William D Rooney1, Fergus Coakley4, and Mark Garzotto2,3
1Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR, United States, 2Portland VA Medical Center, Portland, OR, United States, 3Urology, Oregon Health & Science University, Portland, OR, United States, 4Diagnostic Radiology, Oregon Health & Science University, Portland, OR, United States
A two-step approach that first determines the diffusion constant (D) then the pseudo-perfusion parameters (D*, f) is used to quantify IVIM parameters. Results show that the new approach returns more consistency parametric maps and is favored by AIC.
Figure 1. Two single-voxel data sets that resulted in a narrower (a,c) and a wider (b,d) b-range in D quantification. Starting with a linear regression of log(S/S0) vs. b for b-values within 400-1000 s/mm2, the R2 (red symbols in c, d) were calculated. Each subsequent linear-regression fitting involved an additional data point from the previous DWI frame (smaller b value). a,b: demarcate “optimal range” as black symbols with linear-regression lines. c,d: show R2 plot against addition b points (abscissa direction: right to left). The maximum R2 values are indicated with blue arrows.
Figure 2. a: ADC map from one subject. b: bmin map determined using the R2 approach. c: a binary map for pixels with AIC model selection favoring the two-step modeling approach. The lesion ROI is indicated in red.
Prostate cancer detection with biophysical modeling of diffusion and relaxometry
Gregory Lemberskiy1,2, Yousef Mazaheri3, Herbert Alberto Vargas3, Ricardo Otazo3, Els Fieremans1, and Dmitry S Novikov1
1Radiology, New York University School of Medicine, New York, NY, United States, 2Microstructure Imaging INC, New York, NY, United States, 3Memorial Sloan Kettering Cancer Center, New York, NY, United States
3 prostate cancer patients with PIRADS≥4 lesions were images with a multi-echo/multi-diffusion time protocol. We find that varying the echo time for prostate cancer diffusion weighted imaging increases ADC for benign tissue while minimally affecting the malignant tissue.       
Figure 2: Echo time dependence on $$$T_2w$$$ and $$$ADC$$$. (A) Diffusion-free $$$T_2w$$$ images $$$S|_{b=0}(T_E)$$$ and (B) $$$ADC$$$ maps for increasing $$$T_E$$$ for patient 1. For each image, the corresponding histograms are shown for benign transition zone (blue) and PIRADS-5 lesion (red). The mean and standard deviation of the $$$T_E$$$ dependence on (C) $$$T_2w$$$ and (D) $$$ADC$$$ is extrapolated for benign and malignant transition zone. At long $$$T_E$$$, the benign tissue $$$ADC$$$ increases, while the lesion $$$ADC$$$ is nearly constant.
Figure 3: Area under the curve (AUC) plotted as a function of TE, separating between benign and malignant transition zone in 3 patients.
Breast MRI combined with clinicopathologic characteristics for Preoperative Prediction of Axillary Lymph Node Metastasis in Breast Cancer
Mei Xue1, Lizhi Xie2, and Jing Li3
1Radiology, Cancer Hospital Chinese Academy of Medical Sciences, Beijing, China, 2GE Healthcare, MR Research China, Beijing, Beijing, China, 3Cancer Hospital Chinese Academy of Medical Sciences, Beijing, China
The MR imaging manifestation and clinicopathological features of breast tumor are highly correlated with axillary lymph node metastasis, and it can effectively evaluate axillary lymph node metastasis of breast cancer.
Figure 1. The ADC value and TIC curve of breast tumor
Table 1. MRI manifestations and clinical information of ALNM (+) and ALNM (-)
Assessment with Partial Peripheral Nerve Transection with Diffusion MRI
Isaac Vicente Manzanera Esteve1, Angel F Farinas1, Alonda C Pollins1, Wesley P Thayer1, Mark Does1, and Richard Dortch1
1VUIIS, Vanderbilt University Medical Center, Nashville, TN, United States
High-resolution DTI of ex vivo rat sciatic nerve yields FA values decreased with increasing cut depth at 4 weeks. By week 12, the three partial cuts showed elongated FA distributions, most likely representing regions with regenerated (high FA values) and degenerated axons (low FA values).
Representative tractography from crush and partial cuts nerve (25%, 50% and 75%). Color-coded tracks of FA, FEFA (V1*FA), track length and MD shown.
Split violin plots of A) FA, B) RD, C) AD for sham, crush, and partial cuts nerves at 4 (left, purple) and 12 weeks (right, yellow). Boxplots for each cohort/time are given in red for comparison along with the p-values for Wilcoxon rank-sum tests between 4 and 12 weeks. Note that while significant differences were observed for all cohort/indices across the two times, this does not tell the complete story given the heterogeneous recovery observed in the partial cut samples at 12 weeks (broad distributions shown in the violin plots).
Characterisation of placentome function using combined diffusion-relaxometry MRI and flow anisotropy
Dimitra Flouri1,2, Jack RT Darby3, Stacey L Holman3, Sunthara R Perumal4, Anna L David5,6, Andrew Melbourne1,2, and Janna L Morrison3
1School of Biomedical Engineering & Imaging Sciences, King's College London, London, United Kingdom, 2Department of Medical Physics & Biomedical Engineering, University College London, London, United Kingdom, 3Early Origins of Adult Health Research Group, University of South Australia, Adelaide, Australia, 4Preclinical Imaging and Research Laboratories, South Australian Health and Medical Research Institute, Adelaide, Australia, 5Institute for Women's Health, University College London, London, United Kingdom, 6NIHR University College London Hospitals Biomedical Research Center, London, United Kingdom
This study characterises diffusion and perfusion properties of the placenta such as the apparent diffusion coefficient, T2 measurements, fractional anisotropy and perfusion fraction derived from IVIM-analysis on sheep placental to validate new imaging markers of placental function.   
Figure 1: Figure shows example of the ADC, T2 and FA maps of a single subject.
Figure 3: Box-plots summarising results over the 9 singleton pregnancies. Each plot shows: the median (red line), the 25th and 75th percentile (grey box) and individual means of each subject ROIs (circles).
Tracing and Therapeutic Evaluation of Transplanted Mesenchymal Stem Cell in The Spinal Cord Injury of Beagles using Diffusion Tensor Imaging
Junting Zou1, Jilei Zhang2, Yuanyuan Xie3, yunpeng Shen4, Jiacheng Du4, Yang Chen4, Yang Chen4, Bing Zhang3, and Xiaoli Mai5
1Nanjing Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China, 2Clinical Science, Philips Healthcare, Shanghai, China, 3Nanjing Drum Tower Hospital, Nanjing, China, 4Southeast University, Nanjing, China, 5Radiology, Nanjing Drum Tower Hospital, Nanjing, China
The DTI can be of great value in the dynamic evaluation of morphological and neurological changes in beagles after TSCI. The FA value can satisfactorily evaluate the completeness of the fiber tracts after SCI and the repair of them by stem cells.
Figure 4: Dynamic changes of FA value after TSCI. ROI 1 to 4 represent injured and uninjured side of the injury site and rostral to the injury site. A. Group C: The FA value of all ROIs decreases with time, probably for limited self-repair ability to recover from SCI. B. Group T: Changes of FA value in the three uninjured areas are consistent and is higher than that in the injured area, where it increases with time. C. Group M: The FA value of the injured area increases with time, suggesting that MSCs may repair injured fiber tracts. D. The DTT modeling can observe that the fiber tracts are broken.
Figure 5: Pathological and immunohistochemical examination results. T6-28d: CD90+CD105 immunofluorescent staining confirms that there exists SPIO in living hUC-MSCs. T3-75d: CD90+CD105 immunofluorescent staining finds that MSC presents abnormal living cell morphology. It can be speculated that transplanted MSCs have died or differentiated, and this needs further confirmation. T5-105d: PB staining finds that iron exists in the spinal cord gap rather than in the living cells. C2-120D: No blue-staining areas can be observed and this is a blank control group.
Mono-exponential bi-exponential and stretched-exponential diffusion imaging in characterization of nonalcoholic fatty liver disease
Xianfu Luo1, Jing Ye1, Weiqiang Dou2, Jun Sun1, and Wei Xia1
1Radiology, Clinical Medical School of Yangzhou University, Northern Jiangsu People’s Hospital, Yangzhou, China, 2GE Healthcare,MR Research China, Beijing, China
Stretched-exponential DWI performed as well as bi-exponential DWI and better than mono-exponential DWI in the noninvasive characterization of NAFLD severity.
 
Fig. 2 A rabbit with a high-fat/cholesterol diet feeding for 8 weeks. (a) axial imaging with b value of 0 s/mm2, ADC, D, D*, f, DDC and α pseudo-color maps (b-g) from monoexponential, biexponential ,and stretched-exponential DWI models were 1.002×10-3mm2/s, 0.812×10-3mm2/s, 13.731×10-3mm2/s, 29.102%, 0.763×10-3mm2/s, 0.859, respectively. Histological specimen (h) (magnification, ×200). S=stomach, L=liver, SC=spinal canal.
Fig.3 Compare receiver operating characteristic curve for (a) bi-exponential vs. mono-exponential model; (b) stretched-exponential vs. mono-exponential model in distinguishing NASH from borderline or less severity group.