MRI of the intracranial corticospinal tracts in amyotrophic and primary lateral sclerosis

Our aim was to investigate the corticospinal tracts (CST) in motor neurone disease, using MRI, and to correlate findings with clinical data. We studie d 31 patients with amyotrophic (ALS) and eight with primary lateral scleros is (PLS). The signal from the CST was classified into four grades on T2-wei ghted images, and compared to T2-weighted images of 37 age-matched control subjects. No abnormalities were seen in the CST on T1-weighted images and w ere rarely evident on proton-density weighting. Variable high signal in the CST was found on T2-weighted images in 35 patients, and in 29 control subj ects. Our grades 0 and 1. were more frequent in control subjects, grades 2 and 3 more frequent in patients. We found no correlation between the high s ignal and clinical data, including the duration of the illness. We therefor e conclude that this technique is neither sensitive nor specific except in grade 3 which is quite specific for ALS. In half the patients we found atro phy of the superior parietal gyrus, which merits further study.