title: Measuring carotid stenosis on contrast-enhanced magnetic resonance angiography: diagnostic performance and reproducibility of 3 different methods.
abstract: OBJECTIVE
  The aim of this study was to compare diagnostic performance and reproducibility of 3 different methods of quantifying stenosis on contrast-enhanced magnetic resonance angiography (CEMRA), with intra-arterial digital subtraction angiography (DSA) as the reference standard.
  
  
  METHODS
  167 symptomatic patients scheduled for DSA, after screening Doppler ultrasound, were prospectively recruited to undergo CEMRA. Severity of stenosis was measured according to the North American Symptomatic Trial Collaborators (NASCET), European Carotid Surgery Trial (ECST), and the common carotid (CC) methods. Measurements for each method were made for 284 vessels (142 included patients) on both CEMRA and DSA in a blinded and randomized manner by 3 independent attending neuroradiologists.
  
  
  RESULTS
  Significant differences in prevalence of severe stenosis were seen with the 3 methods on both DSA and CEMRA, with ECST yielding the least and NASCET the most cases of severe stenosis. Overall, all 3 methods performed similarly well in terms of intermodality correlation and agreement. No significant differences in interobserver agreement were found on either modality. With CEMRA, however, we found a significantly lower sensitivity for detection of severe stenosis with ECST (79.8%) compared with NASCET (93.0%), with DSA as reference standard.
  
  
  CONCLUSIONS
  Uniformity of carotid stenosis measurement methods is desirable because patient management may otherwise differ substantially. All 3 methods are adequate for use with DSA. With CEMRA, however, this study supports use of the NASCET method because of improved sensitivity for detecting severe stenosis.
authors.affiliation: University Department of Radiology, Addenbrooke's Hospital, Cambridge, United Kingdom.
authors.forename: Jean Marie K S
authors.initials: JM
authors.lastname: U-King-Im
authors.forename: Rikin A
authors.initials: RA
authors.lastname: Trivedi
authors.forename: Justin J
authors.initials: JJ
authors.lastname: Cross
authors.forename: Nicholas J P
authors.initials: NJ
authors.lastname: Higgins
authors.forename: William
authors.initials: W
authors.lastname: Hollingworth
authors.forename: Martin
authors.initials: M
authors.lastname: Graves
authors.forename: Ilse
authors.initials: I
authors.lastname: Joubert
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Kirkpatrick
authors.forename: Nagui M
authors.initials: NM
authors.lastname: Antoun
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Gillard
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction; D016893:Carotid Stenosis / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D003287:Contrast Media; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015995:Prevalence; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016037:Single-Blind Method
chemical_list: D003287:Contrast Media