HYPOINTENSE MULTIPLE-SCLEROSIS LESIONS ON T1-WEIGHTED SPIN-ECHO MAGNETIC-RESONANCE IMAGES - THEIR CONTRIBUTION IN UNDERSTANDING MULTIPLE-SCLEROSIS EVOLUTION

The predictive value of T2-weighted imaging in multiple sclerosis is o nly moderate, due to low specificity of high signal on such images. Am ong new MR techniques with acclaimed higher pathological specificity, hypointense lesions on moderately T1-weighted spin echo images show im proved correlation with disability. The degree of hypointensity of so called black holes correlates with loss of magnetisation transfer, a m arker of matrix destruction. Severe tissue loss is also shown histopat hologically in a postmortem MR study of black holes. In this review un resolved issues regarding black holes are discussed including standard isation of sequences, definition of hypointensity, interobserver varia tion in measuring lesion load with this technique, and significance of acute black holes. The role of black holes in monitoring treatment ef ficacy is as yet unexplored.