title: Noninvasive detection of vertebral artery stenosis: a comparison of contrast-enhanced MR angiography, CT angiography, and ultrasound.
abstract: OBJECTIVE
  Vertebral stenosis is associated with a high risk of recurrent stroke, but noninvasive imaging techniques to identify it have lacked sensitivity. Contrast-enhanced MR angiography and CT angiography have been recently developed and appear to have better sensitivity. However, no prospective studies have compared both of these techniques with ultrasound against the gold standard of intra-arterial angiography in the same group of patients.
  
  
  METHODS
  Forty-six patients were prospectively recruited in whom intra-arterial angiography was being performed. Contrast-enhanced MR angiography, CT angiography, and duplex ultrasound were also performed. Angiographic images were analyzed blinded to patient identity by 2 experienced neuroradiologists.
  
  
  RESULTS
  Contrast-enhanced MR angiography had the highest sensitivity and specificity (Radiologist 1, 0.83 and 0.91, respectively; Radiologist 2, 0.89 and 0.87) for detecting >or=50% stenosis. CT angiography had good sensitivity (Radiologist 1, 0.68; Radiologist 2, 0.58) and excellent specificity (Radiologist 1, 0.92; Radiologist 2, 0.93), whereas duplex had low sensitivity (0.44) but excellent specificity (0.95). For vertebral origin stenosis >or=50%, sensitivities were similar for contrast-enhanced MR angiography (Radiologist 1, 0.91; Radiologist 2, 0.82) but relatively higher for CT angiography (Radiologist 1, 0.82; Radiologist 2, 0.82) and duplex (0.67).
  
  
  CONCLUSIONS
  Contrast-enhanced MR angiography is the most sensitive noninvasive technique to detect vertebral artery stenosis and also has high specificity. CT angiography has good sensitivity and high specificity. In contrast, ultrasound has low sensitivity and will miss many vertebral stenoses.
authors.affiliation: Clinical Neuroscience, St George's University of London, London, UK.
authors.forename: Sofia
authors.initials: S
authors.lastname: Khan
authors.forename: Philip
authors.initials: P
authors.lastname: Rich
authors.forename: Andrew
authors.initials: A
authors.lastname: Clifton
authors.forename: Hugh S
authors.initials: HS
authors.lastname: Markus
mesh_terms: D000328:Adult; D000368:Aged; D000792:Angiography / Q000592:standards; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000592:standards*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed / Q000592:standards*; D018616:Ultrasonography, Doppler, Duplex / Q000592:standards*; D014715:Vertebrobasilar Insufficiency / Q000175:diagnosis / Q000000981:diagnostic imaging*