[Extracranial carotid artery disease assessed by contrast enhanced three-dimensional MR angiography: correlation with carotid ultrasonography].

Purpose: To evaluate the imaging features of extracranial carotid stenosis and to compare the findings with contrast enhanced three-dimensional MR angiography(CE 3D-MRA) with those of carotid ultrasonography(CUS).

Materials And Methods: Both studies were performed in 24 patients(48 carotid arteries) with extracranial carotid arteriosclerotic stenosis. Based on the CUS findings, the degree of stenosis was classified into four grades: normal, mild; 1-39%, moderate; 40-69%, severe; and 70-99%, occlusion. The presence or absence of ulceration, as well as high-grade turbulence (HGT) at the stenotic portion, was also assessed by CUS. Furthermore, according to the findings of CE 3D-MRA, stenosis was again classified into four types: normal(n = 4), narrow(n = 26), signal void(n = 10), and occlusion(n = 8).

Results: Both studies correctly identified occlusion in 8 arteries. Of 19 arteries that were classified as having mild or moderate stenosis on CUS, 16(84%) were narrow on CE 3D-MRA. On the other hand, of 20 arteries classified as showing severe stenosis on CUS, 10(50%) and 10(50%) were classified as the narrow type and signal-void type, respectively, on CE 3D-MRA. Signal void was only seen in the severe stenosis group. Ulceration was detected more frequently in the signal-void type than in the narrow type (7/10 vs. 5/10). In addition, the incidence of HGT in the signal-void type was significantly higher than that in the narrow type(9/10 vs. 3/10: p < 0.02).

Conclusion: CE 3D-MRA shows the features of extracranial carotid stenosis more reliably than CUS. In addition, signal void detected on CE 3D-MRA may reflect severe carotid stenosis with HGT.