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目的评价多层螺旋CT(MSCT)测定冠状动脉内斑块密度的可靠性及影响因素。方法选用4具成年人尸体心脏标本,将取自标本心室内血栓和心包脂肪颗粒(大小分别为2．0、1．5、1．0、0．5 mm)置入冠状动脉模拟冠状动脉内斑块。对比剂配成1:30、1:40、1:50 3种浓度注入冠状动脉内。原始数据以2种不同层厚(1．00、0．75 mm)重建横断面图像。结果当对比剂浓度为1:30时,血栓CT值分别为109 HU(层厚1．00 mm、大小2．0 mm)、115 HU(层厚1．00 mm、大小1．5 mm)、101 HU(层厚0．75 mm、大小2．0 mm)、113 HU(层厚0．75 mm、大小1．5 mm);脂肪CT值分别为-23 HU(层厚1．00 mm、大小2．0 mm)、-17 HU(层厚1．00 mm、大小1．5 mm)、-9 HU(层厚1．00 mm、大小1．0 mm)、-27 HU(层厚0．75 mm、大小2．0 mm)、-19 HU(层厚0．75 mm、大小1．5 mm)、-13 HU(层厚0．75 mm、大小1．0 mm)。当对比剂浓度为1:40时,血栓CT值分别为79 HU (层厚1．00 mm、大小2．0 mm)、87 HU(层厚1．00 mm、大小1．5 mm)、115 HU(层厚1．00 mm、大小1．0 mm)、73 HU(层厚0．75 mm、大小2．0 mm)、80 HU(层厚0．75 mm、大小1．5 mm)、110 HU(层厚0．75 mm、大小1．0 mm);脂肪的CT值分别为-31 HU(层厚1．00 mm、大小2．0 mm)、-22 HU(层厚1．00 mm、大小1．5 mm)、-10 HU(层厚1．00 mm、大小1．0 mm)、-35 HU(层厚0．75 mm、大小2．0 mm)、-25 HU(层厚0．75 mm、大小1．5 mm)、-19 HU(层厚0．75 mm、大小1．0 mm)。当对比剂浓度为1:50时,血栓CT值分别为53 HU(层厚1．00mm、大小2．0 mm)、60 Hu(层厚1．00mm、大小1．5 mm)、63 HU(层厚1．00 mm、大小1．0 mm)、51 HU(层厚0．75 mm、大小2．0 mm)、64 HU(层厚0．75 mm、大小1．5 mm)、67 HU(层厚0．75 mm、大小1．0 mm)、145 HU(层厚0．75 mm、大小0．5 mm);脂肪的CT值分别为-39 HU(层厚1．00 mm、大小2．0 mm)、-28 HU(层厚1．00 mm、大小1．5 mm)、-22 HU(层厚1．00 mm、大小1．0 mm)、17 HU(层厚1．00 mm、大小0．5 mm)、-41 HU(层厚0．75 mm、大小2．0 mm)、-36 HU(层厚0．75 mm、大小1．5 mm)、-27 HU(层厚0．75 mm、大小1．0 mm)、3 HU(层厚0．75 mm、大小0．5 mm)。血栓的密度值与层厚无关(t=-0．143,P>0．05),但与斑块大小(t=-6．624,P<0．05)和对比剂浓度(t=-8．184,P<0．05)相关。层厚这个因素没有统计学意义可能是由于1．00与0．75 mm的层厚过于接近,以及样本量较少所致。层厚(t=-2．595, P<0．05)、斑块大小(t=-12．369,P<0．05)和对比剂浓度(t=-7．814,P<0．05)均为影响脂肪密度值的因素。结论冠状动脉斑块的密度值与斑块大小、层厚及对比剂浓度相关。
Objective To evaluate the reliability and influencing factors of multi-slice spiral CT (MSCT) in determining the density of plaque in coronary artery. Methods Four adult cadaver hearts were selected and placed in the coronary arteries of coronary arteries from the ventricular thrombus and pericardial fat granules (2.0, 1.5, 1.0 and 0.5 mm in size) Plaque. Contrast agent dubbed 1:30, 1:40, 1:50 3 concentrations injected into the coronary artery. Raw data Reconstructed cross-sectional images in 2 different layer thicknesses (1.00,0.75 mm). Results When the contrast medium concentration was 1:30, the CT values of thrombus were 109 HU (thickness 1.00 mm, size 2.0 mm), 115 HU (thickness 1.00 mm, size 1.5 mm) 101 HU (layer thickness 0.75 mm, size 2.0 mm), 113 HU (layer thickness 0.75 mm, size 1.5 mm); CT values of fat were -23 HU (thickness 1.00 mm, Size 2.0 mm), - 17 HU (layer thickness 1.00 mm, size 1.5 mm), - 9 HU (layer thickness 1.00 mm, size 1.0 mm), - 27 HU .75 mm, 2.0 mm in size), - 19 HU (thickness 0.75 mm, size 1.5 mm), - 13 HU (thickness 0.75 mm, size 1.0 mm). When the contrast agent concentration was 1:40, the CT values of thrombus were 79 HU (thickness 1.00 mm, size 2.0 mm), 87 HU (thickness 1.00 mm, size 1.5 mm), 115 HU (layer thickness 1.00 mm, size 1.0 mm), 73 HU (layer thickness 0.75 mm, size 2.0 mm), 80 HU (layer thickness 0.75 mm, size 1.5 mm) 110 HU (layer thickness 0.75 mm, size 1.0 mm); fat CT values were -31 HU (thickness 1.00 mm, size 2.0 mm), -22 HU (thickness 1.00 mm, size 1.5 mm), - 10 HU (layer thickness 1.00 mm, size 1.0 mm), - 35 HU (layer thickness 0.75 mm, size 2.0 mm), - 25 HU Thickness 0.75 mm, size 1.5 mm), - 19 HU (thickness 0.75 mm, size 1.0 mm). When the contrast agent concentration was 1:50, the thrombus CT values were 53 HU (thickness 1.00 mm, size 2.0 mm), 60 Hu (thickness 1.00 mm, size 1.5 mm), 63 HU ( Layer thickness 1.00 mm, size 1.0 mm), 51 HU (layer thickness 0.75 mm, size 2.0 mm), 64 HU (layer thickness 0.75 mm, size 1.5 mm), 67 HU (Thickness 0.75 mm, size 1.0 mm), 145 HU (thickness 0.75 mm, size 0.5 mm); fat CT values were -39 HU (thickness 1.00 mm, size 2.0 mm), - 28 HU (thickness 1.00 mm, size 1.5 mm), - 22 HU (thickness 1.00 mm, size 1.0 mm), 17 HU (thickness 1.00 mm, size 0.5 mm), - 41 HU (thickness 0.75 mm, size 2.0 mm), - 36 HU (thickness 0.75 mm, size 1.5 mm), - 27 HU 0.75 mm in thickness and 1.0 mm in size), 3 HU (thickness 0.75 mm, size 0.5 mm). Thrombus density was independent of layer thickness (t = -0.143, P> 0.05), but not significantly correlated with plaque size (t = -6.624, 8.184, P <0.05). This factor of layer thickness is not statistically significant, probably due to the too close layer thicknesses of 1.00 and 0.75 mm, and the small sample size. (T = -2.595, P <0.05), plaque size (t = -12.369, P <0.05) and contrast agent concentration (t = -7.814, P < 05) are the factors affecting the value of fat density. Conclusions The density of coronary plaque is related to plaque size, thickness and concentration of contrast medium.