[Neurological deterioration induced by giant intracranial aneurysms even though these aneurysms had not ruptured; mural hemorrhage and intraluminal thrombosis].

The authors report two cases of intracranial giant aneurysms inducing acute neurological deterioration even though rupture of the aneurysms had not occurred. Neurological aggravation was attributable to the acute swelling of the aneurysmal mass after intramural hemorrhage in one case, and the formation of rapid and massive intraluminal thrombosis in another case. MRI confirmed these mechanisms in both cases. MRI is very useful for demonstrating mural and intraluminal pathologies involving giant aneurysms.