[Intracranial hemorrhages in the magnetic resonance tomogram. Studies on sensitivity, on the development of hematomas and on the determination of the cause of the hemorrhage].

One hundred and forty-six intracranial hematomas in 129 patients were examined by MRI (136 examinations) and CT (147 examinations). Even using a high field MR system (1.5 T) and gradient-echo sequences, CT was the more sensitive method during the acute phase (46% compared with 93%). During the sub-acute phase, MR was superior to CT (97% compared with 58%), as it was in the chronic phase (93% compared with 17%). Petechial bleedings and discreet foci of contusion could only be demonstrated by MRI. Moreover, MRI showed evidence of residues from hemorrhage (signal reduction due to hemosiderin deposition) long after CT has become normal. Analyses of MRI images allows one to date the bleed and to distinguish between a) the formation of clot in a haemorrhagic cavity, b) bleeding into the tissues and c) a liquefying hematoma. Bearing in mind this classification, the localisation of the hematoma and the clinical findings mostly allow it is possible to determine the cause of the bleeding. Another advantage is the certain detection of vessels supplying arterio-venous malformations and cavernous hemangiomas.