Preoperative diagnosis of carotid artery stenosis: accuracy of noninvasive testing.
OBJECTIVE
Carotid endarterectomy has been shown to be beneficial in symptomatic patients with a severe stenosis (70% to 99%) of the internal carotid artery (ICA). Digital subtraction angiography (DSA) is the standard of reference in the diagnosis of carotid artery stenosis but has a relatively high complication rate. In a diagnostic study we investigated the accuracy of noninvasive testing compared with DSA.


METHODS
In a prospective diagnostic study we performed duplex ultrasound (DUS), magnetic resonance angiography (MRA), and DSA on 350 consecutive symptomatic patients. Stenoses were measured with the observers blinded for clinical information and other test results. Separate and combined test results of DUS and MRA were compared with the reference standard DSA. Only the stenosis measurements of the arteries on the symptomatic side were included in the analyses.


RESULTS
DUS analyzed with previously defined criteria resulted in a sensitivity of 87.5% (95% CI, 82.1% to 92.9%) and a specificity of 75.7% (95% CI, 69.3% to 82.2%) in identifying severe ICA stenosis (70% to 99%). Stenosis measurements on MRA yielded a sensitivity of 92.2% (95% CI, 86.2% to 96.2%) and a specificity of 75.7% (95% CI, 68.6% to 82.5%). When we combined MRA and DUS results, agreement between these 2 modalities (84% of patients) gave a sensitivity of 96.3% (95% CI, 90.8% to 99.0%) and a specificity of 80.2% (95% CI, 73.1% to 87.3%) for identifying severe stenosis.


CONCLUSIONS
MRA showed a slightly better accuracy than DUS in the diagnosis of carotid artery stenosis. To achieve the best accuracy, however, both tests should be performed subsequently.
Nederkoorn
Paul J
PJ
Julius Center for Patient Oriented Research, University Medical Center Utrecht, Utrecht, Netherlands.
Mali
Willem P Th M
WP
Eikelboom
Bert C
BC
Elgersma
Otto E H
OE
Buskens
Erik
E
Hunink
M G Myriam
MG
Kappelle
L Jaap
LJ
Buijs
Pieter C
PC
Wüst
Aloys F J
AF
van der Lugt
Aad
A
van der Graaf
Yolanda
Y
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction / Q000009:adverse effects; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging; D016893:Carotid Stenosis / Q000145:classification / Q000175:diagnosis*; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011300:Preoperative Care; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018616:Ultrasonography, Doppler, Duplex