[Contrast-enhanced MRA of the carotid arteries using 0.5 Tesla: comparison with selective digital angiography].
OBJECTIVE
To assess the feasability, the imaging quality and the effectiveness of contrast-enhanced MRA (CE MRA) using a 0.5 Tesla MR unit in the evaluation of internal carotid artery (ICA) stenosis. Materials and Methods. 29 patients underwent CE MRA and selective digital substraction angiography (DSA). All data were reviewed in a blinded fashion by 2 independant observers. Imaging quality was graded as good, moderate but interpretable, and insufficient. Stenosis was graded according to the NASCET classification from grade 1 to 4, with the following thresholds:<30%,<70%,<99% and occlusion. Inter and intra- observer agreement was evaluated using the kappa index.


RESULTS
Imaging quality was good for 79 arteries, moderate for 24 and insufficient for 13 (k MRA=0.72 and 0.64 respectively for the right and left ICAs). Interobserver agreement was good with values for right/left ICA of 0.84/0.94, 0.72/0.74 respectively for CE-MRA and DSA. For the comparison between CE MRA and DSA, agreement was also good, with values of 0.74 and 0.64 for both readers. Sensitivity of CE MRA in the detection of hemodynamically significant stenosis (>70%) was of 0.95 and 0.94 and specifity of 0.91 and 0.89 respectively for reader n degrees 1 and reader n degrees 2.


CONCLUSIONS
CE MRA using a 0.5T MR unit is a valuable technique in the evaluation of ICA stenosis.
Barbier
C
C
Service d'Imagerie Médicale, Centre Hospitalier Jean Monnet, 3, avenue Robert Schuman, 88021 Epinal Cedex.
Lefèvre
F
F
Bui
P
P
Denny
P
P
Aiouaz
C
C
Becker
S
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction / Q000379:methods / Q000592:standards*; D016893:Carotid Stenosis / Q000145:classification / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003287:Contrast Media; D005240:Feasibility Studies; D005260:Female; D006439:Hemodynamics; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000295:instrumentation* / Q000379:methods / Q000592:standards*; D008297:Male; D008536:Meglumine; D008875:Middle Aged; D015588:Observer Variation; D009942:Organometallic Compounds; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016037:Single-Blind Method
D003287:Contrast Media; D009942:Organometallic Compounds; D008536:Meglumine; C072417:gadoterate meglumine