Extracranial carotid stenosis in Chinese patients with ischemic stroke as indicated by spiral CT angiography and ultrasonography

Objective To compare the findings of extracranial carotid stenosis detected by computerized tomographic angiography (CTA) and ultrasonography (US) in patients with ischemic stroke. Methods Thirty-four inpatients with acute ischemic stroke in the carotid artery territory underwent CTA (reconstructing 3-D images with maximal intensity projection) and US within 2 weeks after the onset. The intra-arterial digital subtract angiography (DSA) was performed in 3 patients as well. The degree of stenosis in each segmental artery was calculated according to the formula recommended by NASCET and ECST. Results Among 34 cases, thirty patients (88.2%) were diagnosed as extracranial carotid atherosclerosis. The stenosis ratios were (34.6±17.8)% and (32.5±13.9)% detected by CTA and US respectively. The overall agreement of the stenosis grades obtained from two methods was 70.9%. When DSA was used as the reference standard, one patient with intracranial aneurysm (ICA) occlusion was diagnosed correctly by CTA, which was misinterpreted as 50% stenosis by US. CTA identified more calcified plaques (40/80, 50.0%) than US did (28/80, 28.8%). In addition, US disco-vered an ulcer in one patient but missed by CTA. Conclusions CTA and US are complementing in diagnosing the extracranial carotid stenosis.