Pseudoaneurysm formation due to rupture of intracranial aneurysms: Case series and literature review

Abstract

Background Intracranial pseudoaneurysm formation due to a ruptured non-traumatic aneurysm is extremely rare. We describe the radiological findings and management of pseudoaneurysms due to ruptured cerebral aneurysms in our case series and previously reported cases. Patients and methods Four additional and 20 reported patients presenting with subarachnoid hemorrhage (SAH) are included. Radiological findings and clinical features of these patients were reviewed. Results In our series, three-dimensional computed tomographic angiography (3D-CTA) and/or angiography showed an irregular- or snowman-shaped cavity extending from the parent artery. The radiological examination additionally revealed delayed filling and retention of contrast medium. These findings were the same as previously reported cases. One patient underwent direct clipping of the true aneurysm. For the other three patients with aneurysms at the basilar and anterior communicating arteries, the true portion of the aneurysm was embolized with platinum coils. During the procedures, care was taken not to insert the coils into the distal pseudoaneurysm portion to prevent rupture. The review of 24 cases revealed that the location of the aneurysms was most frequent in the anterior communicating artery (41.7%), and 86.7% of patients were in a severe stage of SAH (>Grade 3 in WFNS or Hunt & Kosnik grading) implying abundant SAH. Conclusions Pseudoaneurysm formation in SAH after non-traumatic aneurysm rupture is rare. However, in cases with an irregular-shaped aneurysm cavity, pseudoaneurysm formation should be taken into consideration.

Keywords: Pseudoaneurysm; cerebral aneurysm; intracerebral hematoma; subarachnoid hemorrhage.

Figure 1.

(a) CT demonstrating SAH and intracerebral hematoma around A2/3 of the ACA. An aneurysm is demonstrated as a low-density lesion (arrow). (b) 3D-CTA showing an irregular-shaped lesion at A2/3 (arrow). (c) Intra-operative photograph showing a round and thin-walled portion of the aneurysm. (d) The true aneurysm portion is clipped. (e) Microphotograph showing that the specimen is composed of a thrombus without a vascular wall. Hematoxylin and eosin, ×40. CT: computed tomography; SAH: subarachnoid hemorrhage; ACA: anterior cerebral artery; 3D-CTA: three-dimensional computed tomography angiography.

Figure 2.

CT demonstrating SAH (a), and 3D-CTA (b) showing a BA-SCA aneurysm (arrow) and a cavity (arrowhead) extending from the aneurysm. (c) The distal portion of the aneurysm showing delayed CM filling and washout on angiography. (d) Only the proximal portion of the aneurysm is embolized. CT: computed tomography; SAH: subarachnoid hemorrhage; 3D-CTA: three-dimensional computed tomography angiography; BA-SCA: basilar artery-superior cerebellar artery.

Figure 3.

(a) CT demonstrating SAH. (b) 3D-CTA demonstrating an irregular-shaped aneurysm cavity at AComA. (c) Angiography demonstrating an aneurysm at the AComA (arrow). However, an irregular-shaped additional cavity observed on 3D-CTA is not demonstrated. (d) The true aneurysm portion is embolized with platinum coils. A few loops of coils protrude outside the aneurysm. CT: computed tomography; SAH: subarachnoid hemorrhage; 3D-CTA: three-dimensional computed tomography angiography; AComA: anterior communicating artery.

Figure 4.

(a) CT showing SAH. (b) Angiography demonstrating a cavity protruding to the right from the recurrent BA tip aneurysm. Angiography showing delayed filling and washout of CM in the additional cavity. (c) Post-embolization angiography demonstrating complete obliteration of the aneurysm and disappearance of the pseudoaneurysm. CT: computed tomography; SAH: subarachnoid hemorrhage; CM: contrast medium.