MAGNETIC RESONANCE (MR) imaging (MRI) is currently the best paraclinical tool for the diagnosis of multiple sclerosis (MS). Conventional spin-echo images of the brain are routinely used in clinical practice because of their high sensitivity in the detection of lesions of MS. The burden of disease as measured by T2 lesion volume has been used as a quantitative outcome measure in several recent phase 3 MS clinical trials. Interestingly, although MS plaques detected on postmortem examination colocalize with T2 lesions, there is a weak correlation between T2 disease burden and clinical disability. The reason for this poor correlation is not clear. However, one possibility is that the pathologic processes being represented by T2-weighted lesions of the brain are quite diverse. Inflammation, demyelination, edema, gliosis, and axonal loss are all processes that can be represented by T2-weighted images of the MS brain, yet only axonal loss and chronic demyelination would be expected to result in permanent accumulation of neurological disability.
Racke MK, Hawker K, Frohman EM. Multiple Sclerosis and Magnetic Resonance ImagingAdvancement in Linking the Pictures With the Progression. Arch Neurol. 2001;58(1):35-36. doi:10.1001/archneur.58.1.35