Abstract
Magnetic resonance imaging detects blood‐brain barrier disruption after gadolinium‐DTPA enhancement of central nervous system lesions of multiple sclerosis. Experimental allergic encephalomyelitis has many clinical and pathological features in common with multiple sclerosis including alterations in the integrity of the blood‐brain barrier. We have compared T~2~‐weighted cranial MR images with Gd‐DTPA dimeglumine‐enhanced T~1~‐weighted images of myelin bask protein‐induced acute (Days 8–42 postimmunlzation) and central nervous system‐induced chronic‐progressive (Days 70–95 post immunization) forms of experimental allergic encephalomyelitis in the guinea pig. Although animals from both groups had abnormal T~2~‐weighted images, only the myelin bask protein‐acute‐EAE animals (Days 14–24 postimmunlzation) showed enhancement on postcontrast MR studies. The different responses of the acute and chronic diseases may result from different immunogens, severity of disease, or different permeability of the blood‐brain barrier. Therefore, gadolinium‐DTPA‐enhanced, T~1~‐weighted MR images distinguish acutely active and chronic inflammatory lesions in experimental allergic encephalomyelitis.