Computer tomography of ruptured intracranial arteriovenous malformations in the acute stage.

We studied the CT findings of 23 AVM cases confirmed by cerebral angiography and their clinical findings, and discussed mainly the lesions of ruptured AVM in the acute stage. The 10 cases, in which CT was performed within 7 days after the onset of a ruptured AVM, presented with blood stained CSF except for two cases. All of the 10 cases showed intracerebral haemorrhages in the CT findings, and four of these cases were associated with ventricular rupture. In the plain CT of these 10 cases, high density in the cerebral cistern, such as seen in the acute stage of ruptured intracranial aneurysms, was not found except for 1 case. In the enhanced CT within 7 days after the onset of ruptured AVM, no enhanced findings were found in eight cases. On the contrary, in 12 cases in which CT was performed later than the 8th day after the onset, enhanced findings were found in 11 cases. It has been previously reported that SAH is seen in the lesion of ruptured AVM in the acute stage. From our CT findings of ruptured AVM in the acute stage, however, it was concluded that the lesion of a ruptured AVM in the acute stage does not cause SAH but an intracerebral haematoma or ventricular rupture and that blood may enter the CSF only secondarily.