How does the degree of carotid stenosis affect the accuracy and interobserver variability of magnetic resonance angiography?

Citation
Jm. Wardlaw et al., How does the degree of carotid stenosis affect the accuracy and interobserver variability of magnetic resonance angiography?, J NE NE PSY, 71(2), 2001, pp. 155-160
Citations number
12
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Neurology,"Neurosciences & Behavoir
Journal title
JOURNAL OF NEUROLOGY NEUROSURGERY AND PSYCHIATRY
ISSN journal
0022-3050 → ACNP
Volume
71
Issue
2
Year of publication
2001
Pages
155 - 160
Database
ISI
SICI code
0022-3050(200108)71:2<155:HDTDOC>2.0.ZU;2-Y
Abstract
Objectives-The accuracy of magnetic resonance angiography (MRA) was determi ned in patients with recently symptomatic tight (80%-99%) carotid stenosis (on Doppler ultrasound), and the effect of stenosis severity on the accurac y and interobserver variability of MRA was studied. Methods-Forty four consecutive patients undergoing intra-arterial angiograp hy (IAA) before carotid endarterectomy were prospectively studied, in two c entres with identical MR scanners and sequences. All patients had undergone Doppler ultrasound, showing a 70% or worse carotid stenosis on the symptom atic side. MRA and IAA were done during the same admission. The MRA films w ere each independently and blindly read for percentage stenosis (signal gap if present) by four observers. The IA angiograms were read separately by o ne observer, blind to symptoms, and Doppler and MRA results. Results-Signal gaps on MRA were seen in stenoses ranging from 67% to 99% on intraarterial angiography. Magnetic resonance angiograms consistently over estimated the percentage stenosis according to intraarterial angiography. C linically significant misclassification of stenosis occurred according to M RA in 7% of patients, and was more frequent as carotid stenosis increased. Conclusion-Significant diagnostic errors occur with MRA in patients with ti ght carotid stenosis. Any morbidity occurring as a result of misclassificat ion by MRA is likely to be offset by the avoidance of complications; howeve r, this could only be determined with certainty in a randomised controlled trial.