Yield of CT angiography in patients with acute headache, normal neurological examination and normal non-contrast CT: a meta-analysis

Abstract

Background Patients with acute severe headache, normal neurological examination and a normal non-contrast head CT (NCCT) may still have subarachnoid hemorrhage (SAH), cerebral venous thrombosis (CVT), cervical arterial dissection or reversible cerebral vasoconstriction syndrome (RCVS). CT-angiography (CTA) is used increasingly in the emergency department (ED) for evaluating this, but its added value remains controversial.

Methods We retrospectively collected data on the diagnostic yield of CTA in patients with acute severe headache, normal neurological examination and normal NCCT who received additional CTA in the acute phase in two secondary referral centers for vascular neurology. We combined data of our patients with those from the literature and performed a meta-analysis.

Results We included 88 patients from our hospital files and 641 patients after literature search. Of 729 patients 54 had a vascular abnormality on CTA (7.4%; 95%CI 5.5-9.3%). Abnormalities consisted of aneurysms (n=42; 5.4%; 95%CI 3.8-7.0%), CVT (n=3, 0.5%), RCVS (n=4, 0.5%), Moya-Moya syndrome (n=2, 0.3%), arterial dissection (n=2, 0.3%) and ischemia (n=1, 0.1%). Because most of the aneurysms were probably incidental findings, only 12 (1.6%) patients had a clear relation between the headache and CTA findings. The number needed to scan to find an abnormality was 14 overall, and 61 for an abnormality other than an aneurysm. Conclusion Diagnostic yield of CTA in patients with acute headache, normal neurological examination and normal NCCT is low, but because of the possible therapeutic consequences its use might be justified in the emergency setting. Prospective studies confirming these results including cost-effectiveness analyses are needed.