INFLAMMATORY CENTRAL-NERVOUS-SYSTEM DEMYELINATION - CORRELATION OF MAGNETIC-RESONANCE-IMAGING FINDINGS WITH LESION PATHOLOGY

Magnetic resonance imaging (MRI) is widely used to evaluate and monito r disease activity in inflammatory demyelinating central nervous syste m (CNS) diseases such as multiple sclerosis. The present study aimed a t correlating MRI findings with histological parameters in 6 cases of biopsy-proven inflammatory demyelination of the CNS. The earliest stag es of demyelinating activity manifested as almost isointense lesions w ith a massive gadolinium-DTPA (Gd-DTPA) enhancement in T1-weighted sca ns. In T2-weighted scans, early active lesions formed a border of decr eased intensity compared with the lesion center and the perifocal edem a. The morphological correlate of this pattern in our patients was act ivated macrophages in the zone of myelin destruction at the plaque bor der. Late active lesions were hypointense in T1 and hyperintense in T2 scans. Inactive demyelinated and remyelinating lesions were hyperinte nse in T2 scans and enhanced inhomogenously after Gd-DTPA application. T1 scans revealed major differences in the degree of hypointensity th at correlated with the extent of axonal damage, extracellular edema, a nd the degree of demyelination or remyelination.