MRI measures and their relations with clinical disability in relapsing-remitting and secondary progressive multiple sclerosis.

To further evaluate the relationship between clinical disability and Magnetic Resonance Imaging (MRI) lesion burden, we examined 85 patients with clinically definite multiple sclerosis (54 relapsing-remitting and 31 secondary progressive). This cross-sectional study reports on the correlations between total and infratentorial lesion volume on both T1 and T2 weighted images, and overall physical disability measured by Expanded Disability Status Scale, ambulation index and individual functional systems. Assessment of the hypointense lesion load on T1 weighted images rather than the hyperintense lesion load on T2 weighted images at brain MRI was shown to be useful for differentiating relapsing-remitting from secondary progressive Multiple Sclerosis. A weak relationship between disability and total lesion volume on both T1 and T2 weighted images was found in relapsing-remitting Multiple Sclerosis. In secondary progressive Multiple Sclerosis, infratentorial lesion volume on T2 weighted images represents the only marker of disability. Finally, the presence of cerebellar, brainstem and mental impairment was significantly associated to a greater total lesion volume on MRI, while no relationship was found with other functional systems.