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Updated: Jul 26, 2025
Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases
Published on: July 28, 2013
Multi-tensor diffusion abnormalities of gray matter in an animal model of cortical dysplasia
Paulina J Villaseñor1, David Cortés-Servín1, Aylín Pérez-Moriel2
1Instituto de Neurobiología, Universidad Nacional Autónoma de México Campus Juriquilla, Querétaro, Mexico.
Abstract:
Focal cortical dysplasias are a type of malformations of cortical development that are a common cause of drug-resistant focal epilepsy. Surgical treatment is a viable option for some of these patients, with their outcome being highly related to complete surgical resection of lesions visible in magnetic resonance imaging (MRI). However, subtle lesions often go undetected on conventional imaging. Several methods to analyze MRI have been proposed, with the common goal of rendering subtle cortical lesions visible. However, most image-processing methods are targeted to detect the macroscopic characteristics of cortical dysplasias, which do not always correspond to the microstructural disarrangement of these cortical malformations. Quantitative analysis of diffusion-weighted MRI (dMRI) enables the inference of tissue characteristics, and novel methods provide valuable microstructural features of complex tissue, including gray matter. We investigated the ability of advanced dMRI descriptors to detect diffusion abnormalities in an animal model of cortical dysplasia. For this purpose, we induced cortical dysplasia in 18 animals that were scanned at 30 postnatal days (along with 19 control animals). We obtained multi-shell dMRI, to which we fitted single and multi-tensor representations. Quantitative dMRI parameters derived from these methods were queried using a curvilinear coordinate system to sample the cortical mantle, providing inter-subject anatomical correspondence. We found region- and layer-specific diffusion abnormalities in experimental animals. Moreover, we were able to distinguish diffusion abnormalities related to altered intra-cortical tangential fibers from those associated with radial cortical fibers. Histological examinations revealed myelo-architectural abnormalities that explain the alterations observed through dMRI. The methods for dMRI acquisition and analysis used here are available in clinical settings and our work shows their clinical relevance to detect subtle cortical dysplasias through analysis of their microstructural properties.
Insights
Advanced diffusion-weighted MRI (dMRI) detects subtle microstructural changes in focal cortical dysplasia, a cause of drug-resistant epilepsy. This method reveals diffusion abnormalities linked to specific fiber alterations, aiding in early diagnosis.
Area of Science:
- Neuroimaging
- Biomedical Engineering
- Epilepsy Research
Background:
- Focal cortical dysplasias (FCDs) are a leading cause of drug-resistant epilepsy.
- Complete surgical resection of FCDs improves patient outcomes but relies on accurate lesion detection.
- Subtle FCDs are often missed by conventional magnetic resonance imaging (MRI).
Purpose of the Study:
- To evaluate advanced diffusion-weighted MRI (dMRI) descriptors for detecting diffusion abnormalities in an animal model of FCD.
- To correlate dMRI findings with microstructural and myelo-architectural changes in FCD.
- To assess the clinical relevance of advanced dMRI techniques for subtle FCD detection.
Main Methods:
- Induced FCD in 18 animals, scanned using multi-shell dMRI at 30 postnatal days (n=19 controls).
- Applied single and multi-tensor models to dMRI data for quantitative parameter extraction.
- Utilized a curvilinear coordinate system for dMRI parameter analysis across the cortical mantle.
Main Results:
- Identified region- and layer-specific diffusion abnormalities in experimental animals.
- Differentiated diffusion abnormalities associated with altered tangential versus radial cortical fibers.
- Histology confirmed myelo-architectural abnormalities corresponding to dMRI findings.
Conclusions:
- Advanced dMRI descriptors can detect subtle diffusion abnormalities in FCD, reflecting underlying microstructural changes.
- This technique distinguishes alterations in different intra-cortical fiber populations.
- The described dMRI methods are clinically applicable and show promise for detecting subtle FCDs.
