Fifty-three patients with cerebral venous thrombosis (CVT) were explored by MRI. Three types of signal abnormalities were observed in thrombosed sinuses: 1) isosignal on T1-weighted sequence and low-intensity signal on T2-weighted sequence (early stage); 2) high-intensity signal on T1-and T2-weighted sequences (intermediate stage); 3) isosignal on T1-weighted sequence and high-intensity signal on T2-weighted sequence (late stage). Signal abnormalities in dural sinuses enabling CVT to be diagnosed were absent in 2 out of 53 cases. Twenty-six out of 53 patients had venous infarction. These lesions were haemorrhagic in 20 cases. MRI made it possible to follow the course of CVT in 15 cases, showing partial or complete recanalization of the occluded sinuses in 14 cases. Our study confirmed that MRI is an excellent non-invasive method to explore CVT. It diagnoses the venous thrombosis, studies parenchymal lesions and follows the course of CVT under treatment. However, MRI is less sensitive than arteriography, particularly in cases of CVT involving only the cortical veins.