Cerebral Angiography for Evaluation of Patients with CT Angiogram-Negative Subarachnoid Hemorrhage: An 11-Year Experience

Abstract

Background and purpose: CT angiography is increasingly used to evaluate patients with nontraumatic subarachnoid hemorrhage given its high sensitivity for aneurysms. We investigated the yield of digital subtraction angiography among patients with SAH or intraventricular hemorrhage and a negative CTA.

Materials and methods: An 11-year, single-center retrospective review of all consecutive patients with CTA-negative SAH was performed. Noncontrast head CT, CTA, DSA, and MR imaging studies were reviewed by 2 experienced interventional neuroradiologists and 1 neuroradiologist.

Results: Two hundred thirty patients (mean age, 54 years; 51% male) with CTA-negative SAH were identified. The pattern of SAH was diffuse (40%), perimesencephalic (31%), sulcal (31%), isolated IVH (6%), or identified by xanthochromia (7%). Initial DSA yield was 13%, including vasculitis/vasculopathy (7%), aneurysm (5%), arteriovenous malformation (0.5%), and dural arteriovenous fistula (0.5%). An additional 6 aneurysms/pseudoaneurysms (4%) were identified by follow-up DSA, and a single cavernous malformation (0.4%) was identified by MRI. No cause of hemorrhage was identified in any patient presenting with isolated intraventricular hemorrhage or xanthochromia. Diffuse SAH was due to aneurysm rupture (17%); perimesencephalic SAH was due to aneurysm rupture (3%) or vasculitis/vasculopathy (1.5%); and sulcal SAH was due to vasculitis/vasculopathy (32%), arteriovenous malformation (3%), or dural arteriovenous fistula (3%).

Conclusions: DSA identifies vascular pathology in 13% of patients with CTA-negative SAH. Aneurysms or pseudoaneurysms are identified in an additional 4% of patients by repeat DSA following an initially negative DSA. All patients with CT-negative SAH should be considered for DSA. The pattern of SAH may suggest the cause of hemorrhage, and aneurysms should specifically be sought with diffuse or perimesencephalic SAH.

Fig 1.

Noncontrast head CT examples of SAH. Perimesencephalic SAH: axial image from a noncontrast head CT demonstrates acute SAH in the prepontine and interpeduncular cistern, consistent with a perimesencephalic pattern of SAH (A). Sulcal SAH: axial image from a noncontrast head CT demonstrates acute SAH in the left precentral sulcus and in the sulci overlying the left middle frontal gyrus, consistent with a sulcal pattern of SAH (B). Diffuse SAH: axial image from a noncontrast head CT demonstrates acute SAH in the bilateral Sylvian fissures, overlying the sulci of the bilateral temporal lobes, consistent with a diffuse pattern of SAH. Note also intraventricular hemorrhage within the third ventricle (C). Isolated IVH: axial image from a noncontrast head CT demonstrates acute intraventricular hemorrhage casting the right lateral ventricle (D).

Fig 2.

Cerebral arterial vasculitis identified on DSA. A 45-year-old woman who presented with sulcal SAH (arrow) isolated to the left Sylvian fissure (A). A CTA at the time of admission demonstrated multifocal arterial narrowing (arrowheads) within the bilateral anterior and middle cerebral arteries (B). DSA identified more extensive bilateral arterial irregularity with multifocal narrowing and dilation that was consistent with vasculitis.

Fig 3.

Supraclinoid internal carotid artery aneurysm identified on repeat DSA. A 72-year-old man who presented with perimesencephalic SAH that is localized near the right clinoid process (A). An initial CTA performed on the day of presentation did not identify a lesion responsible for the SAH (B). DSA performed on the day after presentation demonstrates relative narrowing of the right supraclinoid internal carotid artery, the right middle cerebral artery, and the right anterior cerebral artery in the anteroposterior (C) and lateral (D) projections, which was thought to represent early vaspospasm. A follow-up DSA was performed 7 days after presentation, which demonstrates an irregular saccular outpouching (arrows) arising from the supraclinoid internal carotid artery in the anteroposterior (E) and lateral (F) projections, consistent with a dissecting aneurysm.

Fig 4.

Basilar artery aneurysm identified on repeat CTA and DSA. A 65-year-old woman who presented with diffuse SAH in the basal cisterns and bilateral Sylvian fissures. Note hydrocephalus (A and D). A maximum-intensity-projection image from a CTA (B) and a DSA (C) performed on the day of presentation demonstrate no evidence of an aneurysm arising from the basilar artery. A follow-up CTA (E) and DSA (F) performed 7 days after presentation demonstrate an aneurysm arising from the posterior aspect of the basilar artery, consistent with a perforator artery aneurysm.