Cerebral aneurysms associated with seizures but without clinical signs of rupture: seemingly distinctive MR imaging findings in two patients

sion. Because seizures are an uncommon presenting feature of intracranial aneurysms, aneurysm is generally not considered in the differential diagnosis of lesions causing seizures. Aneurysms can produce seizures by a number of mechanisms. including compression or infarction of adjacent brain tissue as well as irritation by blood products from subclinical hemorrhage I 1-3]. We present the MR imaging findings in two patients with cerebral aneurysms and seizures in the absence of clinical features of aneurysm rupture. In both cases. we saw abnormal perianeurysmal MR signal within the adjacent temporal lobe, and the MR signal abnormality was associated with findings at surgery of gliotic brain tissue. In one of these patients, who had thrombus found outside the aneurysm at surgery. the abnormal MR signal also indicated subclinical leakage of the aneurysm. We therefore suggest that the finding of perianeurysmal MR signal abnormality should raise the possibility that an aneurysm has caused structural changes in the adjacent brain and serve as evidence to support the role of an aneurysm in producing seizures in individual patients.