Cross-sectional magnetic resonance angiography is accurate in predicting degree of carotid stenosis.
Carotid stenosis is currently estimated using methods based on flow velocity or two-dimensional projection images. Manipulation of magnetic resonance (MR) images in three dimensions (3-D MR) allows for direct measurement of carotid artery cross-sectional luminal area. The objectives of this study were (1) to assess the accuracy of 3-DMR as a technique for estimating carotid artery stenosis, and (2) to compare 3-D MR results with estimates from duplex ultrasound sonography (DUS) and conventional angiography. Twenty-nine patients underwent rapid, contrast-enhanced MRA within 1 month prior to carotid endarterectomy to obtain 3-D angiographic images of the carotid bifurcation. From these data, post-processing software was used to generate a longitudinal axis through the center of the vessel along which orthogonal cross-sectional images were taken. Luminal area measurements at the location of tightest stenosis and the distal normal internal carotid artery were obtained and used to calculate percent area stenosis. Applying the same procedure, 18 en bloc, ex vivo carotid plaques served as the standard against which we compared in vivo 3-D MR measurements at the location of tightest stenosis. Percent stenosis comparisons between MRA, angiography, and duplex ultrasound were also made. Our results showed that the measurement of luminal area by 3-DMR is accurate in predicting the degree of carotid stenosis. Direct measurement of luminal area may overcome limitations inherent to methods that rely on flow velocities and two-dimensional views of the carotid vasculature. A larger prospective study is necessary to confirm the reliability of this technique.
Morasch
Mark D
MD
Division of Vascular Surgery, Northwestern University Medical School, Chicago, IL 60611-2716, USA. mmorasch@nmh.org
Gurjala
Anandev N
AN
Washington
Ebonia
E
Chiou
Andy C
AC
Simonetti
Orlando P
OP
Finn
J Paul
JP
Yao
James S T
JS
D016893:Carotid Stenosis / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D011237:Predictive Value of Tests; D018616:Ultrasonography, Doppler, Duplex