Sensitivity and Specificity of the Hyperdense Artery Sign for Arterial Obstruction in Acute Ischemic Stroke

Abstract

N oncontrast computed tomography (CT) remains the primary imaging modality for hyperacute assessment of stroke in most centers.1 Identifying features of acute ischemic stroke on CT, therefore, remains important for routine practice. Hyperattenuation of a cerebral artery on noncontrast CT in acute ischemic stroke is thought to represent acute thrombus or embolus; the presence of the Hyperdense Artery Sign (HAS), therefore, is a surrogate of arterial obstruction and may provide useful confirmation of the diagnosis of acute ischemic stroke. The sign has been defined as any artery that subjectively appears transiently denser than adjacent or equivalent contralateral vessels 2,3 although objective measures have also been applied. 4 When compared with angiography, previous studies have shown that the HAS is a specific (although false-positives are described) 5 but not sensitive indicator of arterial obstruction. 6,7 To our knowledge, no systematic review and meta-analysis of HAS sensitivity and specificity have been published. The Third International Stroke Trial (IST-3) was a multicenter, randomized controlled trial, which tested intravenous thrombolysis (Alteplase) given within 6 hours of ischemic stroke.8 Baseline (prerandomization) and follow-up (within 48 hours) brain imaging (predominantly noncontrast CT) was performed for all . In some centers, CT or MR angiography (CTA and MRA, respectively) were also routinely obtained prerandomization as part of their local stroke imaging protocol. 9 In a prespecified analysis, we investigated the diagnostic accuracy of HAS for arterial obstruction detected with CTA or MRA and assessed if characteristics of the noncontrast CT scan (slice-thickness), the corresponding angiographic 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...

Initial hospital management of patients with emergent large vessel occlusion (ELVO): report of the standards and guidelines committee of the Society of NeuroInterventional Surgery

“…However, NCCT is suboptimal for the identification of LVOs—a prerequisite to EVT for ELVO. Although the hyperdense middle cerebral artery sign can indicate LVO,20 it may not be sufficiently sensitive to reliably identify patients with ELVO, even with thinner slice acquisition and process optimization 21. In addition, NCCT is not as sensitive in the identification of extremely early ischemic change, and this also has implications before EVT, as will be discussed below.…”

Time-Dependent Thrombus Resolution After Tissue-Type Plasminogen Activator in Patients With Stroke and Mice

“…The diagnosis of arterial thrombus increases with thinner CT slices and in the case of red thrombi; the sensitivity and specificity of 1.25-mm and 1-mm NCCT to diagnosis thrombus in the middle cerebral artery was reported as 100%. [18][19][20] When follow-up NCCT was performed, CT angiography was undertaken additionally to determine arterial occlusion.…”

“…The occlusion site was most commonly in the middle cerebral artery M1 segment (46.2%; n=79), followed by the distal internal carotid artery (26.9%; n=46), middle cerebral artery M2 segment (18.1%; n=31), basilar artery (7.0%, n=12), and posterior cerebral artery (1.8%; n=3). The median initial National Institutes of Health Stroke Scale score was 16 (IQR,[12][13][14][15][16][17][18][19]. Compared with the good volume reduction to intravenous tPA, moderate or nonvolume reduction had higher initial National Institutes of Health Stroke Scale scores and was more likely to receive sequential intra-arterial reperfusion treatment (Table II in …”

Penumbra and re-canalization acute computed tomography in ischemic stroke evaluation: PRACTISE study protocol

“…The hyper dense artery sign, a marker of intracranial vessel obstruction, was reported to have a high specificity but sensitivity of about 52% in a large clinical sample, and its detection is related to scan quality, slice thickness, and clot burden. (39,40) Multimodal imaging provides additional information that can guide treatment decisions. CTA is 83% sensitive and 95% specific for detection of intracranial occlusion in AIS(41) with potential consideration of adjunctive thrombectomy as a treatment option in large artery occlusion.…”