Magnetization transfer imaging in multiple sclerosis

Although conventional T2-weighted magnetic resonance imaging (MRI) is very sensitive for the detection of multiple sclerosis (MS) lesions, it is not without relevant limitations. First, MRI lacks specificity with regard to the heterogeneous pathological substrates of individual lesions,1 and, as a consequence, does not allow the quantification of tissue damage. Specifically, oedema, inflammation, demyelination, remyelination, gliosis and axonal loss2 all lead to a similar appearance of hyperintensity on T2-weighted images. Secondly, T2-weighted images do not delineate tissue damage occurring in the so-called normal-appearing white matter (NAWM), which usually represents a large portion of the brain tissue from MS patients and which is known to be damaged in MS patients.3