CORRELATION BETWEEN MAGNETIC-RESONANCE-IMAGING FINDINGS AND LESION DEVELOPMENT IN CHRONIC, ACTIVE MULTIPLE-SCLEROSIS

Magnetic resonance imaging is a highly sensitive method for the detect ion of the lesions of multiple sclerosis an renders possible the study and the evolution of early lesions. Previous reports on magnetic reso nance imaging following gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) injection demonstrated that new lesions can be recognized b y contrast enhancement. The pathological basis of these observations i s uncertain. We have had the opportunity to study at autopsy the brain of a patient with chronic progressive multiple sclerosis who suffered acute worsening leading to death. Magnetic resonance imaging performe d 10 days and 4 weeks prior to death showed new Gd-DTPA-enhanced lesio ns in the posterior hemispheric white matter adjacent to the lateral v entricles. Light microscopic examination of these areas demonstrated t hem to be fresh lesions comprising intense inflammatory activity and d ense perivascular cuffs within an edematous lesion center and a striki ng parenchymal mononuclear cell infiltration at the margins of the les ions. Lesions that were demonstrated by increased signal on T2-weighte d images, but were not enhanced following administration of Gd-DTPA, w ere all of the chronic type, either inactive or active. None of these showed the intense inflammatory activity of the acute lesions and most displayed fibrous astrogliosis.