Perimesencephalic non-aneurysmal subarachnoid hemorrhage: is there a need for repeat digital subtraction angiography?

Purpose: To assess the diagnostic yield and clinical relevance of repeated digital subtraction angiography (DSA) in patients with spontaneous perimesencephalic non-aneurysmal subarachnoid hemorrhage (PMSAH) and to evaluate DSA-related complication rates.

Methods: Retrospective analysis of 82 patients with PMSAH confirmed by non-contrast CT between March 2002 and February 2025. All patients underwent initial computed tomography angiography (CTA) and first DSA on average within 24 h. If no bleeding source was identified, a second DSA was performed after 10-14 days. Clinical data, radiological findings, and complications were evaluated.

Results: The initial DSA showed no vascular abnormality in 76/82 patients (92.7%). A second DSA was performed in 60/76 cases (78.9%) and identified two small basilar artery aneurysms (3.3%) that were not visible on the initial CTA or DSA but were detectable on repeat 3D rotational angiography (3DRA). Procedure-related complications occurred in three DSAs (2%), including a cerebellar infarct, supratentorial embolism, and local puncture site complication. Most patients had a benign clinical course, and only one in-hospital death was documented.

Conclusion: The diagnostic benefit of repeat DSA in typical PMSAH is low, with no clear therapeutic impact and a relevant risk of complications. Given the benign course of PMSAH and the availability of high-resolution non-invasive imaging such as dual-source, photon-counting CTA, or vessel wall MRI, repeat DSA should be reserved for selected cases with atypical features or clinical deterioration.