Jan Brabec¹, Filip Szczepankiewicz^2,3,4, Patrik Brynolfsson⁵, Lampinen Björn¹, Faris Durmo⁴, Anna Rydelius⁶, Linda Knutsson^1,7, Pia Sundgren^4,8, and Markus Nilsson^4
1Clinical Sciences Lund, Medical Radiation Physics, Lund University, Lund, Sweden, ²Department of Radiology, Brigham and Women's Hospital, Boston, MA, United States, ³Harvard Medical School, Boston, MA, United States, ⁴Clinical Sciences Lund, Diagnostic Radiology, Lund University, Lund, Sweden, ⁵Dept. of Translational Medicine, Division of Medical Radiation Physics, Lund University, Lund, Sweden, ⁶Clinical Sciences Lund, Neurology, Lund University, Lund, Sweden, ⁷Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, ⁸Lund University Bioimaging Center, Lund University, Lund, Sweden

B-tensor encoding enables mapping of the isotropic and anisotropic components of the diffusional kurtosis, which are sensitive to cell eccentricity and variance in cell density, respectively. We measured the kurtosis components in patients with glioma tumors and explored their ability to improve tumor classification. Results showed that the addition of isotropic kurtosis improves the ability to distinguish low- and high-grade gliomas compared with using post-Gd T1w enhancements alone. Also, non-enhancing glioblastomas and oligodendrogliomas could be distinguished based on the within-tumor standard deviation of the isotropic kurtosis.

Guillermo Gallardo¹, Gaston Zanitti², Samuel Deslauriers-Gauthier³, Matthew Higger⁴, Sylvain Bouix⁴, Alfred Anwander⁵, and Demian Wassermann^2
1Neuropsycology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, ²Parietal, Inria Saclay - Ile de France, PAris, France, ³Athena EPI, Universite Cote d’Azur, Inria, Sophia Antipolis, France, ⁴Psychiatry Neuroimaging Laboratory, Brigham and Womens Hospital, Harvard Medical School, Boston, MA, United States, ⁵Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany

White-matter pathologies disrupt the white-matter organization, that manifests as deficits in brain function. When treating such pathologies, it is of great importance to infer which pathways are affected. However, the white-matter lesions hamper the use of tractography to track fiber bundles. In this work, leveraging diffusion imaging, we propose a novel diffusion-driven technique to improve the localization of brain pathways. Aggregating information from few healthy subjects, our technique is able to localize both the affected pathways and the lesion interrupting when tracking is not possible.

André Döring¹, Christian Rummel², Sandra C. Röthlisberger³, Simone Duss³, Corinne Roth³, Claudio Bassetti^3,4, and Roland Kreis^1
1Depts. Radiology and Biomedical Research, University of Bern, Bern, Switzerland, ²Support Center for Advanced Neuroimaging, University Institute for Diagnostic and Interventional Neuroradiology, Bern, Switzerland, ³Sleep-Wake-Epilepsy-Center, University Hospital Bern, Bern, Switzerland, ⁴Dept. of Neurology, University Hospital Inselspital Bern, Bern, Switzerland

Diffusion-weighted MR spectroscopy (DW-MRS) and imaging (DW-MRI) was applied to investigate potential effects of sleep on apparent diffusion coefficients (ADCs) of water and metabolites in human gray matter in 7 healthy subjects. Monitoring the transition from wake to sleep for a period of 4 hours did not reveal any significant alterations, while comparison of night measurements after slight sleep deprivation to morning examinations after a full night’s sleep indicated that ADCs for some metabolites are lower in the morning than before sleep – though these results need corroboration in a larger cohort.

Yi He¹, Henrik Lundell¹, Ines Mexia Rodrigues¹, Matthew D. Budde², Mark D. Does³, Maurice Ptito^4,5, and Tim Bjørn Dyrby^1
1Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark, ²Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, United States, ³Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States, ⁴School of Optometry, Université de Montréal, Montreal, QC, Canada, ⁵Department of Nuclear Medicine, University of Southern Denmark, Odense, Denmark

Myelin-sensitive bound pool fraction (BPF) enables the tracking process of myelination in primate brains. The 3D BPF maps demonstrated rapid development of myelination from a 2-day-old brain to a 12-month-old brain and a slower increase from 12 months to 30 months. Even though the process of myelination is slow, multidimensional diffusion MRI indices are indeed helpful in significantly differentiating the microstructural maturity of primate brains. Our findings suggest that both indices, isotropic kurtosis (MK_I, associated with cell density variance) and microscopic anisotropy (MK_A, correlated with cell eccentricity) are significant imaging markers for microstructural differentiation in the development of primate brains. 

Cui Feng^1,2, Yanchun Wang¹, Guangyu Dan^2,3, Zheng Zhong^2,3, M. Muge Karaman^2,3, Daoyu Hu¹, and Xiaohong Joe Zhou^2,3,4,5
1Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China, ²Center for MR Research, University of Illinois at Chicago, Chicago, IL, United States, ³Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States, ⁴Department of Radiology, University of Illinois at Chicago, Chicago, IL, United States, ⁵Department of Neurosurgery, University of Illinois at Chicago, Chicago, IL, United States

Diffusion-weighted imaging based on apparent diffusion coefficient (ADC) has been used for bladder urothelial carcinoma grading. However, a considerable overlap between the low- and high-grade bladder urothelial carcinoma has hindered its clinical acceptance. We employed high b-value diffusion imaging with a non-Gaussian fractional-order calculus (FROC) diffusion model for grading bladder urothelial carcinoma. Significant differences were observed in the FROC parameters D, β and μ, between the low- and high-grade urothelial carcinoma. The combination of the FROC parameters provided substantially better performance than ADC. These findings indicate a promising role of FROC parameters for characterizing bladder urothelial carcinoma and beyond.

Yao-Wen Liang¹, Ching-Wen Chang¹, Ssu-Ju Li¹, Ting-Chun Lin¹, Hsin-Tzu Lu¹, You-Yin Chen¹, and Yu-Chun Lo^2
1National Yang-Ming University, Taipei, Taiwan, ²Taipei Medical Unversity, Taipei, Taiwan

Microbiota-gut-brain axis, a bidirectional communication, was proposed as an important role in Alzheimer’s disease (AD). However, the correlation between gut microbiota and brain microstructure in AD remained unclear. Triple-transgenic mouse models of AD were used to investigate brain-behavior-gut-microbiome interaction. Diffusion MRI, behavior tasks, and intestinal bacteria gene analysis were applied in this study. The findings implied that the altered brain microstructure and atypical distribution of gut microbiota were associated with the cognitive dysfunction in AD.

Lee Bremner Reid¹, Eloy Martínez-Heras², Magí Andorrà Inglés², Elisabeth Solana², Sara Llufriu², José V Manjón³, and Jurgen Fripp^1
1The Australian e-Health Research Centre, CSIRO, Brisbane, Australia, ²Center of Neuroimmunology, Laboratory of Advanced Imaging in Neuroimmunological Diseases, Hospital Clinic Barcelona, Institut d'Investigacions Biomediques August Pi i Sunyer and Universitat de Barcelona, Barcelona, Spain, ³ITACA, Universitat Politècnia de València, Valencia, Spain

The optic radiation (OR), is often severed during temporal lobe resection, resulting in permanent quadrantanopia. To date all published tractography methods that delineate the OR require manual input (e.g. region-of-interest placement and adjustment), or appear to underestimate Meyer’s Loop, limiting their widespread clinical adoption. Here, we present and validate the CONSULT pipeline for OR delineation. This pipeline accepts unprocessed DICOM images as input and produces realistic subject-specific segmentations of the OR, including Meyer’s Loop, without need for any human input. Its validation in 183 datasets demonstrated plausible delineations that are in line with previous dissection studies.

Xiudong Shi¹, Weitao Yang², Qiong Ma¹, and Yuxin Shi^1
1Shanghai public health clinical center, Fudan University, Shanghai, China, ²The Institute for Biomedical Engineering & Nano Science, Tongji University, Shanghai, China

Estimating the gross tumor volume by measuring the physical diameters of the tumor with calipers is a common method for evaluating the efficacy of photodynamic therapy (PDT). In this study, the optimal time for determining the efficacy of PDT treatment based on morphological and functional magnetic resonance (MR) imaging techniques is determined.

Laura D. Reyes¹, Amritha Nayak^1,2, Alzheimer’s Disease Neuroimaging Initiative *³, and Carlo Pierpaoli^1
1NIBIB, National Institutes of Health, Bethesda, MD, United States, ²Henry M. Jackson Foundation, Bethesda, MD, United States, ³Alzheimer’s Disease Neuroimaging Initiative, Los Angeles, CA, United States

In this study, we used a biexponential dual compartment diffusion tensor imaging (DTI) model to characterize different pools of parenchymal water to investigate CSF-like free water and parenchymal diffusivity in childhood, early adulthood, and elderly adulthood, and examine how they change across the lifespan. We identified age-related changes in the contribution of parenchymal and CSF-like free water to age-related changes in overall diffusivity that can be linked to changes in tissue microstructure.