[NMR and CT studies in acute and late-stage cerebral infarct]

MR offers an additional non-invasive means for the investigation of cerebro-vascular disease. This new digital imaging method competes with CT. Twenty-four patients with cerebral infarcts were examined by CT and MR; of these, 12 were in the acute stage of necrosis and resorption, and 12 were examined after six weeks following the formation of cysts and glial scars. Because of the increased relaxation time of T1 and T2, there is a large signal difference between infarcted and normal brain. Consequently, cerebral infarcts can be clearly recognised during the first 24 hours. MR also has advantages in demonstrating infarcts in the pons and medulla and if one wishes to avoid contrast enhancement during CT. Problems may arise in differentiating fresh infarcts from haemorrhage and from gliomas. At the present time, the length of the procedure and its high cost justify MR in exceptional circumstances only.