Computer tomography of the cerebrum in multiple sclerosis.

One hundred and ten patients with multiple sclerosis (MS) were examinated with computer tomography (CT) of the brain with the 160 X 160 matrix EMI scanner. Eighty-two areas of low X-ray attenuation around the ventricular system were found in 40 cases (36%), particularly adjacent to the anterior and posterior horns and trigones. These brain volumes with low attenuation are considered to represent the well known large periventricular plaques of MS. The mean plaque volume was 1.26 cm3 and mean attenuation value 9.5 EMI units, which was more than 5 units lower than that of the surrounding brain tissue. Contrast enhancement provided no further information. Periventricular plaques were concomitant to ventricular enlargement and cortical atrophy. By comparison with normal values 49 cases (45%) with atrophy and no plaques were found, while only 20 MS patients (18%) had normal EMI scans. There was no difference between duration of disease and age at onset in the three different groups of MS cases.