Subarachnoid Hemorrhage in Which Vessel Wall Imaging by Contrast-enhanced MRI Was Useful for Identifying a Ruptured Aneurysm

Abstract

Introduction: Recent reports have suggested that contrast-enhanced magnetic resonance imaging (MRI) vessel wall imaging (VWI) is useful for identifying ruptured aneurysm walls. Here, we report a case in which a ruptured aneurysm among multiple cerebral aneurysms was accurately detected using preoperative VWI.

Case: An 82-year-old woman with impaired consciousness (Japan Coma Scale [JCS] III-100) was admitted to the emergency department. A head computed tomography (CT) scan revealed a diffuse subarachnoid hemorrhage (SAH), with the hematoma predominantly localized in the suprasellar and posterior basal cisterns, whereas the interhemispheric fissure contained relatively smaller amounts of hematoma. Contrast-enhanced CT showed an upward-projecting anterior communicating artery (Aco-mA) aneurysm approximately 2.5 mm in size, with fusiform dilation of the basilar artery. Determining the bleeding source based solely on hematoma distribution and aneurysm morphology was challenging. Postcontrast-enhanced MRI demonstrated no dissection of the basilar artery. However, black-blood magnetic resonance imaging (3D fast spin-echo [3D-FSE]) using gadolinium (Gd) revealed enhancement of the wall of the AcomA aneurysm, suggesting it as the source of SAH. The patient underwent microsurgical clipping of the aneurysm on an emergency basis. Intraoperatively, a partially thrombosed bleb was identified at the apex of the aneurysm where a relatively dense hematoma was detected. The aneurysm bled easily upon dissection, confirming the AcomA aneurysm as the source of bleeding. The postoperative course was favorable. On day 41, a ventriculoperitoneal shunt was placed for hydrocephalus. The patient was discharged with a modified Rankin Scale (mRS) score of 4, 70 days after admission. Retrospectively, the intensity of the thrombus in the AcomA aneurysm was locally higher, with a stalk ratio of 0.83, a value consistent with a ruptured aneurysm. The enhancement of the ruptured aneurysm wall may be associated with inflammation and thrombus formation. Based on the contrast intensity and pattern, post-contrast enhancement VWI can more sensitively identify the source of bleeding in patients with multiple aneurysms.