Magnetisation transfer imaging in multiple sclerosis

Magnetisation transfer imaging (MTI) is a magnetic resonance imaging (MRI) technique that has a higher specificity than conventional Ta-weighted scans to the heterogeneous pathological substrates of multiple sclerosis (MS) le sions. This review outlines the contribution of MTI in the study of lesion evolution and in the assessment of disease burden in MS. MTI studies of ind ividual MS lesions confirm the pathological heterogeneity of T2-weighted MR I abnormalities and the potential role of unenhanced T1-weighted hypointens ities as specific markers of localised severe white matter disruption. Corr elative cross-sectional and longitudinal studies using MTI and gadolinium ( Gd)-enhanced MRI reveal that MTI findings may vary in lesions with differen t patterns of enhancement, and that MTI abnormalities are closely related t o the onset and recovery of blood-brain barrier disruption in new MS plaque s. Measures obtained from MTI scans using whole-brain histogram analysis ar e highly correlated with the extent of MS abnormalities on conventional MRI scans and predict patients' clinical disability well, since they are sensi tive to the amounts of both macro- and microscopic MS disease burden in the whole brain and in specific regions.