Measuring carotid stenosis on contrast-enhanced magnetic resonance angiography: diagnostic performance and reproducibility of 3 different methods.
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.
U-King-Im
Jean Marie K S
JM
University Department of Radiology, Addenbrooke's Hospital, Cambridge, United Kingdom.
Trivedi
Rikin A
RA
Cross
Justin J
JJ
Higgins
Nicholas J P
NJ
Hollingworth
William
W
Graves
Martin
M
Joubert
Ilse
I
Kirkpatrick
Peter J
PJ
Antoun
Nagui M
NM
Gillard
Jonathan H
JH
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
D003287:Contrast Media