Radiology, Vol 194, 459-467, Copyright © 1995 by Radiological Society of North America
Carotid artery stenosis: clinical efficacy of MR phase-contrast flow quantification as an adjunct to MR angiography
RL Vanninen, HI Manninen, PL Partanen, PA Vainio and S Soimakallio
Department of Clinical Radiology, Kuopio University Hospital, Finland.
PURPOSE: To assess the utility of magnetic resonance (MR) flow
quantification in the evaluation of suspected carotid artery stenosis.
MATERIALS AND METHODS: Fifty-five patients referred for angiography and 10
healthy volunteers underwent Doppler ultrasound, three-dimensional
time-of-flight MR angiography, and MR phase-contrast flow quantification to
measure peak systolic velocity (PSV) and volumetric flow rate (VFR) in the
common and internal carotid arteries distal to the stenosis. RESULTS: PSV
and VFR were significantly lower in the severely (> or = 70%) stenosed
internal carotid arteries (P < .05). The VFR ratio (internal carotid
artery-common carotid artery) achieved 91% overall accuracy for detection
of severe stenosis. Combination of flow data with results of MR angiography
yielded sensitivity of 100% (95% confidence interval, 78%-100%) with a
modest loss in specificity. Doppler and MR measurements of PSV in the
common carotid artery showed significant correlation: volunteers, r = .73;
patients, r = .64. CONCLUSION: MR flow quantification provides information
about the hemodynamic significance of carotid stenosis. As an adjunct to MR
angiography, it may be useful in enabling differentiation of occlusions
from critical stenoses.
