Contrast-enhanced magnetic resonance angiography (CE-MRA) has become a well-established noninvasive imaging method for the
assessment of severe carotid stenosis (70–99% by NASCET criteria). However, CE-MRA is not a standardised technique, but encompasses
different concurrent techniques. This review analyses possible differences. A bivariate random effects meta-analysis of 17
primary diagnostic accuracy studies confirmed a high pooled sensitivity of 94.3% and specificity of 93.0% for carotid CE-MRA
in severe carotid stenosis. Sensitivity was fairly uniform among the studies, while specificity showed significant variation
(
I
2 = 73%). Metaregressions found significant differences for specificity with two covariates: specificity was higher when using
not only maximum intensity projection (MIP) images, but also three-dimensional (3D) images (
P = 0.01). Specificity was also higher with electronic images than with hardcopies (
P = 0.02). The timing technique (bolus-timed, fluoroscopically triggered or time-resolved) did not result in any significant
differences in diagnostic accuracy. Some nonsignificant trends were found for the percentages of severe carotid disease, acquisition
time and voxel size. In conclusion, in CE-MRA of severe carotid stenosis the three major timing techniques yield comparably
high diagnostic accuracy, electronic images are more specific than hardcopies, and 3D images should be used in addition to
MIP images to increase the specificity.
Keywords Magnetic resonance angiography - Carotid stenosis - Carotid artery disease - Sensitivity and specificity - Meta-analysis