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

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

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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