Sensitivity and specificity of the Hyperdense Artery Sign for arterial obstruction in acute ischemic stroke

Grant Mair, Elena Boyd, Francesca Chappell, Ruediger von Kummer, R. Lindley, Peter Sandercock, Joanna Wardlaw, IST-3 Collaborative Group

Research output: Contribution to journalArticlepeer-review


Background and Purpose—In acute ischemic stroke, the hyperdense artery sign (HAS) on noncontrast computed tomography (CT) is thought to represent intraluminal thrombus and, therefore, is a surrogate of arterial obstruction. We sought to assess the accuracy of HAS as a marker of arterial obstruction by thrombus.

Methods—The Third International Stroke Trial (IST-3) was a randomized controlled trial testing the use of intravenous thrombolysis for acute ischemic stroke in patients who did not clearly meet the prevailing license criteria. Some participating IST-3 centers routinely performed CT or MR angiography at baseline. One reader assessed all relevant scans independently, blinded to all other data; we checked observer reliability. We combined IST-3 data with a systematic review and meta-analysis of all studies that assessed the accuracy of HAS using angiography (any modality).

Results—IST-3 had 273 patients with baseline CT or MR angiography and was the largest study of HAS accuracy. The meta-analysis (n=902+273=1175, including IST-3) found sensitivity and specificity of HAS for arterial obstruction on angiography to be 52% and 95%, respectively. HAS was more commonly identified in proximal than distal arteries (47% versus 37%; P=0.015), and its sensitivity increased with thinner CT slices (r=−0.73; P=0.001). Neither extent of obstruction nor time after stroke influenced HAS accuracy.

Conclusions—When present in acute ischemic stroke, HAS indicates a high likelihood of arterial obstruction, but its absence indicates only a 50/50 chance of normal arterial patency. Thin-slice CT improves sensitivity of HAS detection.
Original languageEnglish
Pages (from-to)102-107
Number of pages6
Issue number1
Early online date4 Dec 2014
Publication statusPublished - Jan 2015

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