DETECTION OF CAROTID-ARTERY STENOSES BY MAGNETIC-RESONANCE ANGIOGRAPHY

Magnetic resonance angiography is a relatively new technique of magnetic resonance imaging which is able to provide 3-dimensional reconstructions of vessels without visualization of soft tissues. In order to compare data obtained at magnetic resonance angiography with results of duplex ultrasound and roentgenocontrast angiography 18 patients with suspected carotid artery stenosis were studied by all three methods. Magnetic resonance angiography of carotid bifurcation was performed using 3-dimensional time-of-flight axial angiography and thin (3 mm) 2-dimensional spin-echo sagittal slices at 1. 5T (Magnetom SP63, Siemens). There was good agreement between the three methods. The correlation coefficient between magnetic resonance and ultrasound estimates of carotid stenosis was 0.57 (p<0.04), between estimates obtained by magnetic resonance and contrast angiography 0.91 (p=0.001). In some cases magnetic resonance angiography overestimated degree of stenosis but analysis of spin-echo images improved quantitation of stenoses. Magnetic resonance angiography in combination with spin-echo imaging is a highly informative noninvasive method for detection of extracranial carotid artery stenosis which can provide some additional information to results of duplex ultrasound and can be helpful in selection of patients for invasive contrast angiography.