Diagnostic accuracy of magnetic resonance angiography for internal carotid artery disease: a systematic review and meta-analysis.
OBJECTIVE
Accurate diagnosis of the degree of internal carotid artery (ICA) stenosis is needed for decisions regarding optimal stroke prevention. Noninvasive magnetic resonance angiography (MRA) is being proposed and used as a replacement for the gold standard, intra-arterial angiography. Our purpose was to perform a systematic review and diagnostic meta-analysis to determine the sensitivity and specificity of time-of-flight (TOF) MRA and contrast-enhanced (CE) MRA for the detection of (1) high-grade (> or = 70% to 99%) ICA stenoses; (2) ICA occlusions; (3) moderately severe (50% to 69%) ICA stenoses; and (4) compare the overall accuracy of the 2 MRA techniques.


METHODS
The medical literature on MRA and the diagnosis of ICA steno-occlusive disease was reviewed through the PubMed, EMBASE, and SCOPUS databases. All publication years were included through to November 2006. Studies were eligible for inclusion if they compared the accuracy of TOF or CE MRA for the detection of ICA disease against intra-arterial angiography and reported sufficient data.


RESULTS
The overall sensitivity of TOF MRA for the detection of > or = 70% to 99% ICA stenoses was 91.2% (95% CI: 88.9% to 93.1%) with a specificity of 88.3% (86.7% to 89.7%), whereas the sensitivity of CE MRA was 94.6% (92.4% to 96.4%) with a specificity of 91.9% (90.3% to 93.4%). For the detection of ICA occlusions, the sensitivity of TOF MRA was 94.5% (91.2% to 96.8%) and the specificity was 99.3% (98.9% to 99.6%), whereas the sensitivity and specificity values for CE MRA were 99.4% (96.8% to 100%) and 99.6% (99.2% to 99.9%), respectively. For moderately severe (50% to 69%) stenoses, TOF MRA had a sensitivity of only 37.9% (29.3% to 47.1%) and a specificity of 92.1% (89.6% to 94.1%); for CE MRA, the pooled sensitivity value was somewhat better at 65.9% (57.0% to 74.0%), whereas the specificity was 93.5% (91.3% to 95.3%).


CONCLUSIONS
TOF MRA and CE MRA showed high accuracy for the detection of high-grade ICA stenoses and occlusions with CE MRA having the edge over TOF MRA, but had only poor (TOF MRA) to fair (CE MRA) sensitivity for the detection of moderately severe stenoses.
Debrey
Sarah M
SM
Stroke Neuroscience Unit, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD, USA.
Yu
Hua
H
Lynch
John K
JK
Lövblad
Karl-Olof
KO
Wright
Violet L
VL
Janket
Sok-Ja D
SJ
Baird
Alison E
AE
D002340:Carotid Artery Diseases / Q000473:pathology*; D002343:Carotid Artery, Internal / Q000473:pathology*; D006801:Humans; D018810:Magnetic Resonance Angiography / Q000379:methods* / Q000592:standards*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity