Diffusion tensor MRI tractography and cognitive impairment in multiple sclerosis
Mesaros S et al. – Lesions in strategic brain white matter (WM) tracts contribute to cognitive impairment in multiple sclerosis (MS) through a multisystem disconnection syndrome.Methods
- Brain dual-echo, T1-weighted, and DT MRI data were acquired from 82 patients with MS.
- DT tractography was used to produce maps of white matter (WM) tracts involved in cognition.
- The sensory thalamocortical projections and optic radiations were studied as “control” WM tracts.
- The contribution of global brain damage (T2 lesion volume, normalized brain volume, gray matter [GM] volume, WM volume, DT MRI measures of normal-appearing WM and GM damage) and damage to selected WM tracts to overall cognitive impairment and to impairment at individual neuropsychological tests was assessed using a random forest (RF) analysis.
- Thirty-three patients had cognitive impairment.
- The majority of MRI measures differed significantly between cognitively impaired and cognitively preserved (CP) patients.
- Significant correlations were found between performance in the majority of neuropsychological tests and global or regional brain damage (r ranging from -0.60 to 0.57).
- The RF analysis showed a high performance in classifying cognitively impaired vs CP patients, with a classification (C)–index = 76.8, as well as in classifying patients' impairment in individual neuropsychological tests (C-index between 75.6% and 86.6%).
- Measures of lesional damage in cognitive-related tracts, rather than measures of normal-appearing WM damage in the same tracts or global brain/WM/GM damage, resulted in the highest classification accuracy.