Diffusion Tensor Imaging to Map Brain Microstructural Changes in CADASIL.

Area of Science:

• Neuroimaging
• Neurology
• Radiology

Background:

• Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a genetic condition affecting small blood vessels in the brain.
• Diffusion tensor imaging (DTI) is a sensitive MRI technique for assessing white matter integrity.

Purpose of the Study:

• To map the spatial distribution of brain microstructural changes in CADASIL patients using DTI.
• To investigate the correlation between DTI-derived indices and the extent of white matter hyperintensities (T2 signal abnormalities).

Main Methods:

• 18 CADASIL patients and 18 healthy controls underwent 3 Tesla MRI.
• Tract-based spatial statistics (TBSS) analyzed DTI indices: mean diffusivity (MD), fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), and mode of anisotropy (MO).
• DTI indices were correlated with the extended Fazekas visual scale for T2 hyperintensity.

Main Results:

• CADASIL patients exhibited widespread symmetric increases in MD/RD and decreases in AD/FA/MO across cerebral white matter, thalami, and corpus callosum.
• Additional increases in RD were noted in the pons, midbrain, cerebellar peduncles, and cerebellar white matter.
• Only FA showed a negative correlation with the extended Fazekas visual score.

Conclusions:

• Brain damage in CADASIL involves extensive microstructural changes affecting major white matter pathways.
• These findings suggest impaired intra- and inter-hemispheric, thalamocortical, and cerebrocerebellar connections in CADASIL.
• The severity of microstructural alterations is linked to the extent of T2 hyperintensity.