title: Time-resolved contrast-enhanced magnetic resonance angiography of the carotid arteries: diagnostic accuracy and inter-observer variability compared with selective catheter angiography.
abstract: OBJECTIVE
  To assess the diagnostic accuracy and interobserver variability of contrast-enhanced magnetic resonance angiography (CE-MRA) in a time-resolved technique compared with digital subtraction angiography (x-ray DSA) in patients with suspected stenoses of the internal carotid artery.
  
  
  METHODS
  A total of 43 patients were enrolled in this prospective study. All patients underwent selective x-ray DSA involving a total of 84 carotid arteries. CE-MRA was performed in a time-resolved technique with a fast gradient-echo sequence on a 1.5 T MR scanner: TR 3.8 milliseconds, TE 1.49 milliseconds. Four consecutive measurements, each a duration of 10 seconds, were performed with omission of measuring bolus transit time. Four independent radiologists scored the degree of stenosis. The interobserver variability was calculated for CE-MRA and x-ray DSA.
  
  
  RESULTS
  In the 43 cases, at least one MRA measurement showed arterial contrast without venous degradation. Compared with x-ray DSA the mean sensitivity and specificity for grading stenosis > or = 70% were 98% and 86%, respectively. The interobserver agreement was substantial with no significant difference between CE-MRA (kappa value 0.794) and x-ray DSA (kappa value 0.786).
  
  
  CONCLUSIONS
  The short acquisition time of a fast CE-MRA sequence allows a selective visualization of the internal carotid arteries without degradation from venous enhancement. It is a reliable method with a good interobserver agreement.
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction; D002339:Carotid Arteries; D002343:Carotid Artery, Internal; D016893:Carotid Stenosis / Q000175:diagnosis*; D003287:Contrast Media; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D013997:Time Factors
chemical_list: D003287:Contrast Media