Comparison of MR imaging with clinical history in the identification of hemorrhage in patients with cerebral arteriovenous malformations.

Twenty-nine patients with true arteriovenous malformations as diagnosed by MR imaging or angiography were examined by MR to detect the presence of hemosiderin deposition, a marker for remote hemorrhage. The resulting information was compared with the clinical record to determine the frequency with which MR demonstrated prior hemorrhagic episodes where no clinical evidence for such episodes existed. Twenty (69%) of 29 patients with arteriovenous malformations showed evidence of acute or older hemorrhage. In four (14%) of 29 cases MR showed a hypointense signal on long TR images, suggesting hemosiderin, but no clinical history could account for prior hemorrhage. Additionally, six (21%) of 29 patients had a clinical history suggestive of acute hemorrhage, but no evidence of bleeding was found on MR. The presence of prior or current hemorrhage is critical to deciding whether to surgically resect the arteriovenous malformation or to treat it conservatively, because of the high rate of rebleeding in patients presenting with hemorrhage or those with a history of this disorder. For this reason, MR imaging has an important role in the management of patients with arteriovenous malformations.