The aim of this study was to compare the diagnostic accuracy of 3D
time-of-flight (TOF-MRA) and contrast-enhanced (CE-MRA) magnetic
resonance angiography at 3 T for detection and quantification
of proximal high-grade stenosis using multidetector computed
tomography angiography (MDCTA) as reference standard.
The institutional ethics committee approved this prospective study.
A total of 41 patients suspected of having internal carotid artery
(ICA) stenosis underwent both MDCTA and MRA. CE-MRA and TOF-MRA were
performed using a 3.0-T imager with a dedicated eight-element
cervical coil. ICA stenoses were measured according to the North
American Symptomatic Carotid Endarterectomy Trial criteria and
categorized as 0-25 % (minimal), 25-50 % (mild),
50-69 % (moderate), 70-99 % (high grade), and
100 % (occlusion). Sensitivity and specificity for the
detection of high-grade ICA stenoses (70-99 %) and ICA
occlusions were determined. In addition, intermodality agreement was
assessed with κ-statistics for detection of high-grade ICA
stenoses (70-99 %) and ICA occlusions.
A total of 80 carotid arteries of 41 patients were reviewed. Two
previously stented ICAs were excluded from analysis. On MDCTA, 7
ICAs were occluded, 12 ICAs presented with and 63 without a
high-grade ICA stenosis (70-99 %). For detecting
70-99 % stenosis, both 3D TOF-MRA and CE-MRA were
91.7 % sensitive and 98.5 % specific, respectively.
Both MRA techniques were highly sensitive (100 %), and
specific (CE-MRA, 100 %; TOF-MRA, 98.7 %) for the
detection of ICA occlusion. However, TOF-MRA misclassified one
high-grade stenosis as occlusion. Intermodality agreement for
detection of 70-99 % ICA stenoses was excellent between
TOF-MRA and CE-MRA [κ = 0.902, 95 %
confidence interval (CI) = 0.769-1.000], TOF-MRA and
MDCTA (κ = 0.902, 95 %
CI = 0.769-1.000), and CE-MRA and MDCTA
(κ = 0.902, 95 %
CI = 0.769-1.000).
Both 3D TOF-MRA and CE-MRA at 3 T are reliable tools for
detecting high-grade proximal ICA stenoses (70-99 %). 3D
TOF-MRA might misclassify pseudo-occlusions as complete occlusions.
If there are no contraindications for CE-MRA, CE-MRA is recommended
as primary MR imaging modality.
Weber J, Veith P, Jung B, Ihorst G, Moske-Eick O, Meckel S, Urbach
H, Taschner C A. MR angiography at 3 Tesla to assess proximal
internal carotid artery stenoses: contrast-enhanced or 3D
time-of-flight MR angiography?. Clin Neuroradiol 2014; 25:41-8.