내경동맥 협착의 평가에 있어서 조영증강 자기공명혈관조영과 삼차원 비약시간 자기공명혈관조영의 비교

Abstract

B a c k g ro u n d: Contrast-enhanced magnetic resonance angiography (CEMRA) has begun to replace time-offlight magnetic resonance angiography (TOFMRA) because it reduces imaging time and improves signal-to-noise ratio. However CEMRA may overestimate the degree of arterial stenosis. O b j e c t i v e s: With digital subtraction angiography (DSA) as a reference standard, we tried to find out if CEMRA overestimates carotid artery stenosis more than TOFMRA. M e t h o d s: From April 2003 to August 2005, fifty-five consecutive patients underwent TOFMRA, CEMRA and DSA. The degree of stenosis was measured using North American Symptomatic Carotid Endarterectomy Trial (NASCET) method and classified as mild (1~49%), moderate (50~69%), and severe (70~99%). Results: Five patients were excluded because of the poor quality of images. In 100 carotid arteries of 50 patients, 23 arteries had various degree of stenosis, 8 were occluded, and 69 were normal. CEMRA overestimated the severity of carotid stenosis in 8 out of 92 but TOFMRA did in 3 out of 92. We calculated the agreement by κin CEMRA vs. DSA (κ= 0.79, p < 0.05) and TOFMRA vs. DSA (κ= 0.92, p < 0.05). For detection of severe stenosis, CEMRA had the sensitivity of 100% and the specificity of 90% while TOFMRA had 100% and 97.5%, r e s p e c t i v e l y. The rate of misclassification of patients as an appropriate candidate for carotid endarterectomy (CEA) was 40.4% in CEMRA and 14.8% in TOFMRA. Conclusion: CEMRA has many advantages over TOFMRA but it tends to overestimate the severity of carotid stenosis. The results of CEMRA should be compared with those of TOFMRA or DSA when surgical intervention is considered. (Korean Journal of Stroke 2005;7(2): 172~178)