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Updated: Jul 11, 2026
Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases
Published on: July 28, 2013
Characteristics of abnormal diffusivity in normal-appearing white matter investigated with diffusion tensor MR
M I Makki1, D C Chugani, J Janisse
1Carman and Ann Adams Department of Pediatrics, Children's Hospital of Michigan, Detroit, MI 48201, USA. malek@pet.wayne.edu
Background And Purpose:
Although patients with tuberous sclerosis complex (TSC) manifest various structural abnormalities, we hypothesized that white matter (WM) structures that appear normal on conventional MR imaging may be accompanied by microstructural changes, such as gliosis and myelinization defects. Our objective was to determine in vivo whether there was evidence for WM microstructural changes by using diffusion tensor imaging (DTI).
Materials And Methods:
We used DTI to evaluate diffusivity and anisotropy in normal-appearing WM (NAWM) of 6 children with TSC and 12 age-matched control subjects. The anterior and posterior limbs of the internal capsule, the external capsule, and the genu and splenium of the corpus callosum were assessed. We hypothesized that previously reported DTI abnormalities of NAWM in patients with TSC may not be equal in all diffusion directions as measured by the major, middle, and minor eigenvalues.
Results:
When combining NAWM regions in patients with TSC, we observed a significant increase in mean diffusivity (P = .003) and a decrease in anisotropy (P = .03) compared with those of controls. However, the increase in diffusivity was more pronounced in directions orthogonal to the axons measured by the minor and middle eigenvalues (P = .005) than by the major eigenvalue (P = .02).
Conclusion:
Our findings revealed a decrease in anisotropy and an increase in longitudinal and radial diffusivities in NAWM beyond the location of TSC lesions seen on conventional MR imaging. The axonal microstructural changes suggested by our study may be related to changes in myelin packing due to giant cells accompanied by gliosis and myelination defects known to occur in TSC WM.
Insights
Diffusion tensor imaging (DTI) revealed microstructural white matter (WM) changes in children with tuberous sclerosis complex (TSC). These findings suggest myelin packing alterations and gliosis in normal-appearing WM, even outside visible lesions.
Area of Science:
- Neuroimaging
- White Matter Microstructure
- Diffusion Tensor Imaging
Background:
- Tuberous sclerosis complex (TSC) is associated with various structural abnormalities.
- White matter (WM) changes may exist in TSC even when appearing normal on conventional MRI.
Purpose of the Study:
- To investigate in vivo microstructural changes in normal-appearing white matter (NAWM) in children with TSC using diffusion tensor imaging (DTI).
- To determine if DTI abnormalities in NAWM of TSC patients differ across diffusion directions.
Main Methods:
- DTI was used to assess diffusivity and anisotropy in NAWM of 6 children with TSC and 12 controls.
- Specific WM regions analyzed included the internal capsule, external capsule, and corpus callosum.
- Analysis focused on major, middle, and minor eigenvalues to evaluate directional diffusion differences.
Main Results:
- NAWM in TSC patients showed significantly increased mean diffusivity and decreased anisotropy compared to controls.
- The increase in diffusivity was more pronounced in directions perpendicular to axons (minor and middle eigenvalues).
Conclusions:
- Microstructural changes, including decreased anisotropy and increased radial/longitudinal diffusivities, were found in NAWM of TSC patients.
- These axonal changes likely relate to myelin packing alterations, gliosis, and myelination defects characteristic of TSC.
