Diffusion tensor imaging analysis of tumefactive giant brain lesions in multiple sclerosis

Area of Science:

• Neuroimaging
• Radiology
• Neurology

Background:

• Diffusion tensor imaging (DTI) measures water diffusion in brain tissue.
• Inflammation disrupts tissue, increasing diffusivity and decreasing directionality.
• Tumefactive giant brain lesions (TGL) are a rare manifestation of multiple sclerosis (MS).

Purpose of the Study:

• To quantify tissue damage in MS-related TGL using MRI and DTI.
• To compare DTI metrics of TGL with acute MS lesions.
• To assess micro-structural changes in TGL over time.

Main Methods:

• Regions of interest were defined on TGL and acute MS lesions.
• Key DTI metrics analyzed included volume, apparent diffusion coefficient (ADC), fractional anisotropy (FA), axial diffusivity (λ||), and radial diffusivity (λ⊥).

Main Results:

• TGL exhibited significantly higher ADC, λ||, and λ⊥, and lower FA compared to acute MS lesions (P <.001).
• Follow-up MRI/DTI after 120 days showed decreased TGL volume, reduced ADC, λ||, and λ⊥, and increased FA (P < .01).

Conclusions:

• TGL display DTI characteristics indicative of intense acute inflammation within the MS lesion spectrum.
• DTI metrics are sensitive to micro-structural changes in TGL, reflecting progression from acute inflammation to recovery and reorganization.