Yield of Repeat 3D Angiography in Patients with Aneurysmal-Type Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE:Aneurysmal-type subarachnoid hemorrhage is a serious disease with high morbidity and mortality. When no aneurysm is found, the patient remains at risk for rebleeding. Negative findings for SAH on angiography range from 2% to 24%. Most previous studies were based on conventional 2D imaging. 3D rotational angiography depicts more aneurysms than 2D angiography. The purpose of this study was to evaluate the yield of repeat 3D rotational angiography in patients with aneurysmal-type SAH with negative initial 3D rotational angiography findings and to classify the initial occult aneurysms.MATERIALS AND METHODS:Between March 2013 and January 2016, 292 patients with SAH and an aneurysmal bleeding pattern were admitted. Of these 292 patients, 30 (10.3%; 95% CI, 7.3%–14.3%) had initial negative 3D rotational angiography findings within 24 hours. These patients underwent a second 3D rotational angiography after 7–10 days.RESULTS:In 8 of 30 patients (26.7%; 95% CI, 14.0%–44.7%) with initial negative 3D rotational angiography findings, a ruptured aneurysm was found on repeat 3D rotational angiography. Three of 8 initial occult aneurysms were very small (1–2 mm), 2 were supraclinoid carotid artery dissecting aneurysms (2 and 8 mm), 2 were small (1 and 3 mm) basilar perforator aneurysms, and 1 was a 3-mm vertebral artery dissecting aneurysm.CONCLUSIONS:In 10% of patients with aneurysmal-type SAH, initial 3D rotational angiography findings were negative, and in 1 in 4, repeat 3D rotational angiography demonstrated a ruptured aneurysm. Initial occult aneurysms were dissecting aneurysms of perforators or main arteries or were very small (1–2 mm) or both. Our results indicate that repeat 3D rotational angiography is mandatory in patients with initial 3D rotational angiography findings negative for aneurysmal-type SAH.

Subarachnoid hemorrhage with an aneurysmal bleeding pattern (aSAH) is a serious disease with high morbidity and mortality. In 80%–90% of patients with aSAH, an aneurysm can be found as the cause of hemorrhage,¹ and early repair is advocated to prevent recurrent hemorrhage.The incidence of angiograms negative for aSAH has been reported to range from 2% to 24% in various studies.^2,3 In some of these patients, the source of the hemorrhage is an occult aneurysm, but intracranial artery dissections, dural arteriovenous malformations, micro-AVMs, trauma, bleeding disorders, substance abuse, or other causes should also be considered. Even though no aneurysm is found, these patients are at risk for early rebleed with an inherent risk of morbidity and death.⁴ An aneurysm is not depicted on first angiography for several reasons: very small aneurysms, small aneurysms with an intraluminal thrombus, aneurysms on arterial dissections, suboptimal image quality due to technical reasons or in uncooperative patients, and a missed diagnosis of an aneurysm.Repeat angiography is advocated to avoid missing a treatable cause of aSAH. Previous studies have demonstrated that repeat angiography after 7–10 days can depict an aneurysm in up to one-third of patients with initial negative angiography findings.^5–8 3D rotational angiography (3DRA) has been proved to depict more aneurysms than 2D DSA.^9,10 In our institution, diagnostic work-up of patients with aSAH now consists of 3DRA of all vessels within 24 hours. With negative findings, 3DRA is repeated. In this study, we evaluated the yield of repeat 3DRA in patients with aSAH with negative initial 3DRA findings. In addition, we classified the initial occult aneurysms.