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 only moderate, due to low specificity of high signal on such images. Among new MR techniques with acclaimed higher pathological specificity, hypointense lesions on moderately T1-weighted spin echo images show improved correlation with disability. The degree of hypointensity of so called black holes correlates with loss of magnetisation transfer, a marker of matrix destruction. Severe tissue loss is also shown histopathologically in a post-mortem MR study of black holes. In this review unresolved issues regarding black holes are discussed including standardisation of sequences, definition of hypointensity, interobserver variation in measuring lesion load with this technique, and significance of acute black holes. The role of black holes in monitoring treatment efficacy is as yet unexplored.