scholarly journals Imaging G-Ratio in Multiple Sclerosis Using High-Gradient Diffusion MRI and Macromolecular Tissue Volume

2019 ◽  
Author(s):  
F. Yu ◽  
Q. Fan ◽  
Q. Tian ◽  
C. Ngamsombat ◽  
N. Machado ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Diffusion Mri ◽  
High Gradient ◽  
Tissue Volume ◽  
Gradient Diffusion ◽  
G Ratio

Characterizing glioma microenvironment with ultra-high gradient diffusion MRI.

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. 2050-2050
Author(s):  
Ina Ly ◽  
Barbara Wichtmann ◽  
Susie Yi Huang ◽  
Aapo Nummenmaa ◽  
Ovidiu Andronesi ◽  
...  
Keyword(s):  
Diffusion Model ◽  
Diffusion Mri ◽  
Volume Fraction ◽  
Response To Treatment ◽  
Imaging Biomarker ◽  
Normal Brain ◽  
Post Contrast ◽  
Major Barrier ◽  
High Gradient ◽  
Gradient Diffusion

2050 Background: The infiltrating nature of gliomas, particularly into the peritumoral area, is a major barrier to improving clinical outcome as microscopic disease remains even after apparent gross total resection. Conventional T1 post-contrast and T2/FLAIR MRI do not capture full tumor extent. A better imaging biomarker is needed to improve differentiation between tumor, peritumoral area and normal brain. Methods: 4 pre-surgical patients with non-enhancing, FLAIR-hyperintense lesions suspicious for glioma underwent ultra-high gradient diffusion MRI on the Connectome MRI scanner, a unique scanner with maximum gradient strength of 300 mT/m enabling mapping of cellular microstructures on a micron-level scale. The FLAIR area was defined as the tumor region of interest (ROI). Radiographically normal appearing brain up to 1 cm around the FLAIR area was defined as the peritumoral ROI. Using a novel 3 compartment diffusion model (Linear Multiscale Model), the volume fraction of water (VFW) was calculated within restricted (intracellular), hindered (extracellular) and free (CSF) spaces. VFW in the tumor, peritumoral ROI, contralateral normal white matter (WM) and cortex were compared. Results: Within the tumor ROI, the median VFW in the restricted compartment was decreased vs. the peritumoral ROI (↓ 34%), WM (↓ 46%) and cortex (↓ 18%) while median VFW in the hindered compartment was increased vs. the peritumoral ROI (↑ 26%), WM (↑ 54%) and cortex (↑ 25%). Within the peritumoral ROI, median VFW in the hindered compartment was increased compared to WM (↑ 23%). 3 patients had available histopathology revealing isocitrate dehydrogenase-mutant gliomas. Conclusions: Using ultra-high gradient diffusion MRI and a novel diffusion model, we detected distinct diffusion patterns in the tumor and peritumoral area not seen on conventional MRI. Lower VFW in the restricted compartment within the tumor may reflect decreased intracellular water mobility due to enlarged nuclei. Higher VFW in the hindered compartment in the tumor and peritumoral area may reflect higher degree of tissue permeability and edema. MRI-pathology and larger cohort validation studies are underway to elucidate microenvironment changes in response to treatment.

scholarly journals Characterization of Axonal Disease in Patients with Multiple Sclerosis Using High-Gradient-Diffusion MR Imaging

Radiology ◽  
2016 ◽  
Vol 280 (1) ◽  
pp. 244-251 ◽  
Author(s):  
Susie Y. Huang ◽  
Sean M. Tobyne ◽  
Aapo Nummenmaa ◽  
Thomas Witzel ◽  
Lawrence L. Wald ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Mr Imaging ◽  
High Gradient ◽  
Diffusion Mr ◽  
Gradient Diffusion ◽  
Diffusion Mr Imaging

scholarly journals NIMG-09. CHARACTERIZING GLIOMA MICROENVIRONMENT WITH ULTRA-HIGH GRADIENT DIFFUSION MRI

2017 ◽  
Vol 19 (suppl_6) ◽  
pp. vi144-vi144
Author(s):  
Ina Ly ◽  
Barbara Wichtmann ◽  
Susie Huang ◽  
Aapo Nummenmaa ◽  
Ovidiu Andronesi ◽  
...  
Keyword(s):  
Diffusion Mri ◽  
High Gradient ◽  
Gradient Diffusion ◽  
Glioma Microenvironment

scholarly journals Axon diameter index estimation independent of fiber orientation distribution using high-gradient diffusion MRI

NeuroImage ◽  
2020 ◽  
Vol 222 ◽  
pp. 117197 ◽  
Author(s):  
Qiuyun Fan ◽  
Aapo Nummenmaa ◽  
Thomas Witzel ◽  
Ned Ohringer ◽  
Qiyuan Tian ◽  
...  
Keyword(s):  
Fiber Orientation ◽  
Diffusion Mri ◽  
Orientation Distribution ◽  
Axon Diameter ◽  
High Gradient ◽  
Gradient Diffusion ◽  
Fiber Orientation Distribution ◽  
Index Estimation

scholarly journals MR g-ratio-weighted connectome analysis in patients with multiple sclerosis

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Koji Kamagata ◽  
Andrew Zalesky ◽  
Kazumasa Yokoyama ◽  
Christina Andica ◽  
Akifumi Hagiwara ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Network Topology ◽  
Diffusion Mri ◽  
Myelinated Axon ◽  
Brain Network ◽  
Disconnection Syndrome ◽  
Enhanced Sensitivity ◽  
G Ratio ◽  
The Brain ◽  
Limbic Regions

Abstract Multiple sclerosis (MS) is a brain network disconnection syndrome. Although the brain network topology in MS has been evaluated using diffusion MRI tractography, the mechanism underlying disconnection in the disorder remains unclear. In this study, we evaluated the brain network topology in MS using connectomes with connectivity strengths based on the ratio of the inner to outer myelinated axon diameter (i.e., g-ratio), thereby providing enhanced sensitivity to demyelination compared with the conventional measures of connectivity. We mapped g-ratio-based connectomes in 14 patients with MS and compared them with those of 14 age- and sex-matched healthy controls. For comparison, probabilistic tractography was also used to map connectomes based on the number of streamlines (NOS). We found that g-ratio- and NOS-based connectomes comprised significant connectivity reductions in patients with MS, predominantly in the motor, somatosensory, visual, and limbic regions. However, only the g-ratio-based connectome enabled detection of significant increases in nodal strength in patients with MS. Finally, we found that the g-ratio-weighted nodal strength in motor, visual, and limbic regions significantly correlated with inter-individual variation in measures of disease severity. The g-ratio-based connectome can serve as a sensitive biomarker for diagnosing and monitoring disease progression.

scholarly journals High-gradient diffusion MRI reveals distinct estimates of axon diameter index within different white matter tracts in the in vivo human brain

2019 ◽  
Vol 225 (4) ◽  
pp. 1277-1291 ◽  
Author(s):  
Susie Y. Huang ◽  
Qiyuan Tian ◽  
Qiuyun Fan ◽  
Thomas Witzel ◽  
Barbara Wichtmann ◽  
...  
Keyword(s):  
White Matter ◽  
Human Brain ◽  
Diffusion Mri ◽  
Axon Diameter ◽  
White Matter Tracts ◽  
High Gradient ◽  
Gradient Diffusion

scholarly journals Scan-Rescan Repeatability of Axonal Imaging Metrics using High-Gradient Diffusion MRI and Statistical Implications for Study Design

NeuroImage ◽  
2021 ◽  
pp. 118323
Author(s):  
Qiuyun Fan ◽  
Maya N. Polackal ◽  
Qiyuan Tian ◽  
Chanon Ngamsombat ◽  
Aapo Nummenmaa ◽  
...  
Keyword(s):  
Study Design ◽  
Diffusion Mri ◽  
High Gradient ◽  
Gradient Diffusion

scholarly journals Age-related alterations in axonal microstructure in the corpus callosum measured by high-gradient diffusion MRI

NeuroImage ◽  
2019 ◽  
Vol 191 ◽  
pp. 325-336 ◽  
Author(s):  
Qiuyun Fan ◽  
Qiyuan Tian ◽  
Ned A. Ohringer ◽  
Aapo Nummenmaa ◽  
Thomas Witzel ◽  
...  
Keyword(s):  
Corpus Callosum ◽  
Diffusion Mri ◽  
High Gradient ◽  
Gradient Diffusion ◽  
Age Related

scholarly journals Probing mouse brain microstructure using oscillating gradient diffusion MRI

2011 ◽  
Vol 67 (1) ◽  
pp. 98-109 ◽  
Author(s):  
Manisha Aggarwal ◽  
Melina V. Jones ◽  
Peter A. Calabresi ◽  
Susumu Mori ◽  
Jiangyang Zhang
Keyword(s):  
Mouse Brain ◽  
Diffusion Mri ◽  
Gradient Diffusion ◽  
Brain Microstructure

Diffusion MRI and Q-Space Diffusion MRI: From Cerebral Ischemia to Multiple Sclerosis and Beyond

2001 ◽  
pp. 123-145 ◽  
Author(s):  
Yoram Cohen ◽  
Yaniv Assaf ◽  
Revital Nossin-Manor ◽  
Inbal E. Biton
Keyword(s):  
Multiple Sclerosis ◽  
Cerebral Ischemia ◽  
Diffusion Mri
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