Tanami Yutaka, Ikeda Eiji, Jinzaki Masahiro, Satoh Kozo, Nishiwaki Yuji, Yamada Minoru, Okada Yasunori, Kuribayashi Sachio
Department of Pathology, School of Medicine, Keio University, Tokyo, Japan.
J Comput Assist Tomogr. 2010 Jan;34(1):58-63. doi: 10.1097/RCT.0b013e3181b66c41.
To compare the diagnostic performance of computed tomographic (CT) attenuation and CT attenuation ratio at different tube voltages for ex vivo plaque characterization.
Human coronary arteries were obtained at the time of autopsy in 15 subjects. The coronary arteries were serially cut into 5-mm-long segments and scanned ex vivo using 4 sets of tube voltages and tube currents (80 kV, 660 mA; 100 kV, 500 mA; 120 kV, 400 mA; and 140 kV, 340 mA). The CT attenuation value at the center of each plaque was obtained, and the ratio of the CT attenuation value at the 80-kV setting divided by that at the 140-kV setting (Hounsfield ratio [HR], 80:140) was calculated. Separate receiver operating characteristic (ROC) analyses were used to assess the usefulness of the CT attenuation value and the 80:140 HR for the differential diagnosis of lipid-rich plaques from other types of plaques.
A total of 93 coronary plaques were detected macroscopically. Histological examination revealed 39 lipid-rich, 24 calcified, and 30 fibrotic plaques. At all the tube voltages, the CT attenuation values of the lipid-rich plaques were lower than those of the calcified plaques, whereas the CT attenuation values of the lipid-rich and fibrotic plaques overlapped. An ROC analysis showed that the area under the curve (AUC) for the differential diagnosis of lipid-rich plaques from fibrotic plaques was 0.813 at 80 kV, 0.772 at 100 kV, 0.682 at 120 kV, or 0.651 at 140 kV. Regarding the 80:140 HR, the AUC was 0.952 (0.029). The AUC was significantly larger at 80 and 100 kV and 80:140 HR compared with the AUC at 120 kV.
The diagnostic performance of CT analysis for ex vivo plaque characterization was superior at lower energy settings and using the dual-energy method.
比较不同管电压下计算机断层扫描（CT）衰减值和CT衰减率对离体斑块特征的诊断性能。
从15名受试者尸检时获取人类冠状动脉。将冠状动脉连续切成5毫米长的节段，并使用4组管电压和管电流（80 kV，660 mA；100 kV，500 mA；120 kV，400 mA；140 kV，340 mA）进行离体扫描。获取每个斑块中心的CT衰减值，并计算80 kV设置下的CT衰减值除以140 kV设置下的CT衰减值的比值（亨氏比值[HR]，80:140）。采用独立的受试者工作特征（ROC）分析来评估CT衰减值和80:140 HR对富含脂质斑块与其他类型斑块进行鉴别诊断的有用性。
宏观上共检测到93个冠状动脉斑块。组织学检查显示39个富含脂质斑块、24个钙化斑块和30个纤维化斑块。在所有管电压下，富含脂质斑块的CT衰减值低于钙化斑块，而富含脂质斑块和纤维化斑块的CT衰减值有重叠。ROC分析显示，在80 kV时，从纤维化斑块中鉴别富含脂质斑块的曲线下面积（AUC）为0.813，100 kV时为0.772，120 kV时为0.682，140 kV时为0.651。对于80:140 HR，AUC为0.952（0.029）。与120 kV时的AUC相比，80 kV、100 kV和80:140 HR时的AUC显著更大。
在较低能量设置下并使用双能方法时，CT分析对离体斑块特征的诊断性能更佳。
