目的 探讨斑块与主动脉CT值比值(标化CT值)在鉴别冠状动脉脂质与纤维斑块中的价值,并分析其截断值的稳定性.方法 纳入1周内行冠状动脉CT血管成像(CCTA)和血管内超声(IVUS)检查的患者.通过测量全部、4个和2个短轴层面分别获得斑块CT值,测量升主动脉CT值并标化(斑块与主动脉CT值比值).绘制标化CT值和传统CT值的受试者工作特征(ROC)曲线.结果 60例患者共74个斑块,IVUS诊断35个脂质和39个纤维斑块.主动脉与管腔CT值显著相关(r=0.420,P<0.01);全层、4层和2层鉴别冠状动脉脂质与纤维斑块的CT值截断值分别为55 HU、48 HU和52 HU,标化CT值截断值均为0.149;4层传统CT值和标化CT值鉴别脂质和纤维斑块的灵敏度、特异度、阳性预测值(PPV)及阴性预测值(NPV)分别为69%、87%、83%、76%和91%、82%、82%、91%.结论 与传统CT值相比,标化CT值显著提高鉴别脂质和纤维斑块的灵敏度和NPV,同时保持中至高度的特异度和PPV,且具有稳定的截断值.
Objective To explore the value of plaque-to-aorta CT value ratio(standardized CT value)in differentiating coronary lipid and fibrous plaques,and to preliminarily analyze the stability of the cutoff.Methods Patients who underwent coronary computed tomography angiography(CCTA)and intravascular ultrasound(IVUS)within 1 week were included.The plaque CT value was obtained by measuring the all,four and two short-axis planes,respectively.The CT value of the ascending aorta was measured and standardized(plaque-to-aorta CT value ratio).The receiver operating characteristic(ROC)curves of the standardized and the traditional CT values were drawn.Results A total of 60 patients with 74 plaques were included,35 lipid and 39 fibrous plaques were diagnosed by IVUS.The aorta CT value was significantly correlated with the plaque(r=0.420,P<0.01);the cutoffs for the CT value of all,four and two plaque slices were 55 HU,48 HU and 52 HU,respectively,and all there of the cutoffs of standardized CT value were 0.149;the sensitivity,specificity,positive predictive value(PPV)and negative predictive value(NPV)of four-slice traditional and standardized CT values to differentiate lipid and fibrous plaques were 69%,87%,83%,76%and 91%,82%,82%,91%,respectively.Conclusion Compared with traditional CT value,the standardized CT value can greatly improve the sensitivity and NPV in differentiating coronary lipid and fibrous plaques,while maintaining modest to high specificity and PPV.Furthermore,the cutoff is stable.