INTRACRANIAL DISSECTING ANEURYSM CAUSING SUBARACHNOID HEMORRHAGE - THE ROLE OF COMPUTERIZED TOMOGRAPHIC ANGIOGRAPHY AND MAGNETIC-RESONANCE ANGIOGRAPHY

BACKGROUND With increasing frequency, dissecting aneurysms of the intr acranial arteries are recognized as a possible cause of subarachnoid h emorrhage (SAH). In the presence of a dissecting aneurysm, angiographi c changes may be subtle at presentation and correct diagnosis often re quires serial angiograms. We report a patient with a dissecting aneury sm of the anterior cerebral artery (ACA) causing SAH, in whom less inv asive diagnostic tools, such as high-resolution computerized tomograph ic angiography (CTA) and magnetic resonance angiography (MRA), were he lpful in confirming the diagnosis and in following the evolution of th e dissection. CASE PRESENTATION We present this 51-year old woman who experienced the sudden onset of severe headache without associated neu rological deficits. Head CT showed SAH with blood in the interhemisphe ric fissure, suggesting a ruptured ACA aneurysm. Serial cerebral angio grams failed to demonstrate an aneurysmal sac, but showed evolving irr egularities of the ACA consistent with a dissecting aneurysm. These fi ndings were confirmed by CTA and MRA. The patient was treated conserva tively and made an excellent recovery. A MRA obtained 2 months later s howed slight improvement of the previously visualized ACA dilatation. CONCLUSION Serial angiograms are often required to confirm the diagnos is and to follow the evolution of an intracranial dissection. With rec ent advances in neuroradiological techniques, however, critical inform ation can be obtained by less invasive imaging studies, such as CTA an d MRA. (C) 1997 by Elsevier Science Inc.