Background: It is known that 9% to 31% of women and 4% to 14% of men with acute myocardial infarction have normal coronary arteries or nonsignificant coronary disease at angiography. These patients represent a diagnostic and therapeutic challenge. Multislice computed tomography (CT) can noninvasively identify the presence of coronary plaques even in the absence of significant coronary artery stenosis. This study evaluated the role of 64-slice CT, in comparison with coronary angiography, in detecting and characterizing coronary atherosclerosis in patients with acute myocardial infarction without significant coronary artery stenosis.
Methods and results: Thirty consecutive patients with acute myocardial infarction but without significant coronary stenosis at coronary angiography underwent 64-slice CT. All coronary segments were quantitatively analyzed by means of coronary angiography (CA-QCA) and 64-slice CT (CT-QCA). Forty-seven (10.4%) of the 450 coronary segments were not evaluable by CT. The mean proximal reference diameters at CT-QCA and CA-QCA were, respectively, 2.88+/-0.75 mm and 2.65+/-0.9 mm; the overall correlation between CT-QCA and CA-QCA for quantification of reference diameter was r(s)=0.77; P<0.001. The mean percent stenosis was 14.4+/-8.0% at CT-QCA and 4.0+/-11.0% at CA-QCA and the correlation was r(s)=0.11; P=0.03. Overall CT-QCA showed the presence of 50 plaques, of which only 11 were detected by CA-QCA. CT-QCA identified 25 plaques in infarct-related coronary arteries. Positive remodeling was present in 38 of the 50 plaques (76%), with a higher prevalence in the coronary plaques not visualized by CA-QCA (82.1% versus 54.5%).
Conclusions: CT-QCA correlates well with CA-QCA in terms of coronary reference diameter analysis, but not stenosis quantification. Multislice CT can detect coronary atherosclerotic plaques in segments of nonstenotic coronary arteries that are underestimated by CA and may have an incremental diagnostic value for the diagnosis of acute myocardial infarction in patients without significant coronary stenosis at CA.