Non-invasive imaging compared with intra-arterial angiography in the diagnosis of symptomatic carotid stenosis: a meta-analysis

• Published in: The Lancet (British edition) Vol. 367; no. 9521; pp. 1503 - 1512
• Main Authors: Wardlaw, JM, Chappell, FM, Best, JJK, Wartolowska, K, Berry, E
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 06-05-2006; Lancet; Elsevier Limited
• Subjects: Accuracy; Adult; Aged; Aged, 80 and over; Biological and medical sciences; Cardiovascular disease; Cardiovascular system; Carotid Stenosis - diagnostic imaging; Diagnostic tests; Endarterectomy, Carotid; General aspects; Heterogeneity; Humans; Investigative techniques, diagnostic techniques (general aspects); Medical sciences; Middle Aged; Neurology; Radiodiagnosis. Nmr imagery. Nmr spectrometry; Radiography; Radionuclide Imaging; Sensitivity analysis; Stroke; Studies; Systematic review; Ultrasonic imaging; Ultrasonography; Vascular diseases and vascular malformations of the nervous system; Carotid stenosis; Nervous system diseases; Radiodiagnosis; Angiography; Cardiovascular disease; Review; Cerebral disorder; Metaanalysis; Arterial disease; Vascular disease; Medicine; Symptomatology; Blood vessel; Central nervous system disease; Non invasive method; Medical imagery; Circulatory system; Diagnosis; Cerebrovascular disease; Comparative study
• ISSN: 0140-6736; 1474-547X
• DOI: 10.1016/S0140-6736(06)68650-9

Accurate carotid imaging is important for effective secondary stroke prevention. Non-invasive imaging, now widely available, is replacing intra-arterial angiography for carotid stenosis, but the accuracy remains uncertain despite an extensive literature. We systematically reviewed the accuracy of non-invasive imaging compared with intra-arterial angiography for diagnosing carotid stenosis in patients with carotid territory ischaemic symptoms.
We searched for articles published between 1980 and April 2004; included studies comparing non-invasive imaging with intra-arterial angiography that met Standards for Reporting of Diagnostic Accuracy (STARD) criteria; extracted data to calculate sensitivity and specificity of non-invasive imaging, to test for heterogeneity and to perform sensitivity analyses; and categorised percent stenosis by the North American Symptomatic Carotid Endarterectomy Trial (NASCET) method.
In 41 included studies (2541 patients, 4876 arteries), contrast-enhanced MR angiography was more sensitive (0·94, 95% CI 0·88–0·97) and specific (0·93, 95% CI 0·89–0·96) for 70–99% stenosis than Doppler ultrasound, MR angiography, and CT angiography (sensitivities 0·89, 0·88, 0·76; specificities 0·84, 0·84, 0·94, respectively). Data for 50–69% stenoses and combinations of non-invasive tests were sparse and unreliable. There was heterogeneity between studies and evidence of publication bias.
Non-invasive tests, used cautiously, could replace intra-arterial carotid angiography for 70–99% stenosis. However, more data are required to determine their accuracy, especially at 50–69% stenoses where the balance of risk and benefit for carotid endarterectomy is particularly narrow, and to explore and overcome heterogeneity. Methodology for evaluating imaging tests should be improved; blinded, prospective studies in clinically relevant patients are essential basic characteristics.