Basilar artery perforator rupture as the cause of perimesencephalic subarachnoid hemorrhage

J Neurosurg 144:1271–1277, 2026

This clinical study evaluates the etiology of perimesencephalic subarachnoid hemorrhage (pmSAH) by applying high-resolution cone-beam CT (CBCT) during catheter angiography to detect basilar artery perforator outpouchings. The retrospective analysis of 22 pmSAH patients found that CBCT identified basilar perforator pseudoaneurysms in a substantial subset, with conservative management yielding excellent outcomes.

The authors argue that many pmSAHs may be arterial rather than venous in origin when imaged with modern high-resolution CBCT protocols. They recommend heightened suspicion for an arterial source and detailed angiographic CBCT acquisition, while acknowledging limits of retrospective design, variable imaging quality, and unresolved management questions.

Objective High-resolution CBCT performed during catheter angiography was used to better identify the etiology of perimesencephalic SAH (pmSAH), challenging the historical assumption of a venous source.

Methods Retrospective review of pmSAH cases (Jan 2023–Dec 2024) requiring catheter angiography with available, diagnostic-quality CBCT; images were interpreted by two experienced neuroangiographers to consensus.

Cohort Of 152 spontaneous SAH presentations, 22 met Rinkel criteria for pmSAH; after exclusions (alternative causes found, missing/low-quality CBCT), 13 patients remained for CBCT-based imaging analysis.

Key finding In 8/13 (61.5%) analyzed pmSAH cases, CBCT showed a basilar artery perforator focal outpouching consistent with a rupture site (submillimeter, 0.4–0.8 mm).

Anatomy distribution Among the 8 identified perforator lesions, 6 were rostral basilar perforators, with 1 midbasilar and 1 caudal perforator involvement.

Outcomes All pmSAH patients—including those with identified basilar perforator outpouchings—had excellent recovery, with no re-rupture events and no clinically significant vasospasm reported in the series.

Follow-up imaging In patients who underwent follow-up DSA with CBCT, the basilar perforator finding resolved on follow-up imaging.

Conclusion/implication pmSAH should be approached with high suspicion for an arterial etiology (basilar perforator pseudoaneurysm frequently detectable with high-resolution CBCT), and conservative management was associated with excellent outcomes in this cohort.

Preoperative Evaluation of Unruptured Cerebral Aneurysms by Fast Imaging Employing Steady- State Acquisition Image

Neurosurgery 69:412–420, 2011 DOI: 10.1227/NEU.0b013e318213431e

In aneurysm surgery, understanding the microanatomy around the aneurysm such as perforating arteries and cranial nerves is mandatory.

OBJECTIVE: To assess the usefulness in determining the microanatomy around the cerebral aneurysms by the use of fast imaging employing steady-state acquisition (FIESTA) images of magnetic resonance imaging preoperatively, in addition to computed tomography and digital subtraction angiography.

METHODS: Between October 2006 and June 2009, 123 patients with 140 unruptured cerebral aneurysms were treated in our institution. Eighty-two patients were assessed with FIESTA by the operators on the workstation of the magnetic resonance image before surgical clipping of the aneurysms. The small vessels and cranial nerves were confirmed intraoperatively before or after obliteration of the aneurysms.

RESULTS: Sensitivities and specificities of FIESTA imaging were 100% in detecting hypothalamic artery around anterior communicating artery aneurysms, oculomotor nerve attachment to the posterior communicating artery aneurysm domes, and anterior choroidal artery adhesion to the posterior communicating artery aneurysms. This technique was also useful for predicting adhesion between the aneurysm and adjacent main trunks or perforators. Although the specificity was 100%, sensitivity was 56% in detecting vessel adhesion around the middle cerebral aneurysms. This technique can provide limited information in large aneurysms or aneurysms located in minimal cerebrospinal fluid space. The overall outcomes of the patients included 120 excellent recoveries, 1 moderate deficit, 1 severe deficit, and 1 persistent vegetative state according to the Glasgow Outcome Scale.

CONCLUSION: By giving information on the minute anatomical structure around the aneurysm, FIESTA can contribute to thorough preoperative evaluations of cerebral aneurysms.