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Updated: Jul 8, 2026
Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases
Published on: July 28, 2013
Diffusion-tensor MR imaging of cortical lesions in multiple sclerosis: initial findings
Aziz H Poonawalla1, Khader M Hasan, Rakesh K Gupta
1Department of Diagnostic and Interventional Radiology, University of Texas Medical School at Houston, 6431 Fannin St, Houston, TX 77030, USA.
Purpose:
To prospectively perform a direct measurement of fractional anisotropy (FA) and mean diffusivity (MD) in cortical lesions of patients with multiple sclerosis (MS).
Materials And Methods:
The study was approved by the institutional review board and was HIPAA compliant; informed consent was obtained. Magnetic resonance (MR) images, including double inversion-recovery (DIR), phase-sensitive inversion-recovery (PSIR), and diffusion-tensor images, were acquired from nine MS patients with cortical lesions (five women, four men; median age, 47 years) and nine age- and sex-matched volunteer control subjects. Following nonlinear elastically constrained image registration for aligning diffusion-weighted images to DIR images, maps of FA and MD were computed for each subject. Cortical lesions were identified on DIR images and validated by using PSIR images. The diffusion-tensor imaging maps were then overlaid on the coregistered DIR images, and mean FA and MD values were measured in regions of interest drawn on the cortical lesions. Differences between normal gray matter (GM) and cortical lesions were evaluated by using the generalized estimating equation. FA and MD histograms of whole brain and GM (global analysis) in healthy control subjects and MS patients were also computed for comparison with those in previously published studies.
Results:
FA and MD values were significantly higher in cortical lesions compared with similar regions in healthy control subjects. Histogram peak FA was significantly decreased and peak MD was significantly increased in patients relative to control subjects.
Conclusion:
DIR and PSIR combined with nonlinear image registration allowed direct focal measurement of FA and MD in cortical lesions.
Insights
Diffusion tensor imaging reveals higher fractional anisotropy (FA) and mean diffusivity (MD) in multiple sclerosis (MS) cortical lesions. These findings highlight microstructural changes in MS gray matter lesions.
Area of Science:
- Neuroimaging
- Radiology
- Neurology
Background:
- Multiple sclerosis (MS) is a chronic demyelinating disease affecting the central nervous system.
- Cortical lesions are increasingly recognized as significant contributors to MS disability.
- Accurate characterization of MS cortical lesions is crucial for understanding disease progression.
Purpose of the Study:
- To prospectively measure fractional anisotropy (FA) and mean diffusivity (MD) directly within cortical lesions of multiple sclerosis (MS) patients.
- To investigate microstructural differences between MS cortical lesions and normal-appearing gray matter.
Main Methods:
- Acquisition of advanced magnetic resonance imaging (MRI) including diffusion-tensor imaging (DTI), double inversion-recovery (DIR), and phase-sensitive inversion-recovery (PSIR).
- Utilized nonlinear elastic image registration to precisely align diffusion-weighted images with DIR images.
- Defined regions of interest on cortical lesions identified on DIR and validated with PSIR images for FA and MD quantification.
Main Results:
- Significantly elevated FA and MD values were observed in MS cortical lesions compared to healthy control gray matter.
- Analysis of diffusion tensor imaging (DTI) histograms revealed a significant decrease in peak FA and a significant increase in peak MD in MS patients.
- These quantitative DTI metrics indicate distinct microstructural alterations within MS cortical lesions.
Conclusions:
- The combination of DIR, PSIR, and nonlinear image registration enables direct, focal measurement of FA and MD in MS cortical lesions.
- These findings provide direct evidence of microstructural abnormalities in MS cortical lesions using advanced MRI techniques.
- This methodology offers a potential tool for more precise assessment and monitoring of MS neuropathology.
