低浓度对比剂能谱CT单能量成像对提高门静脉图像质量的研究

发布时间：2018-09-17 14:21

【摘要】：目的:探讨宝石CT能谱成像最佳对比噪声比(CNR)单能量图像对提高低浓度对比剂门静脉成像质量的应用价值。方法:将符合纳入标准的136例患者随机分为2组,A组采用高浓度对比剂(350mg I/100mL)和常规CT扫描(1.25mm层厚)、B组采用低浓度对比剂(270mg I/100mL)和宝石CT能谱成像(GSI)。由两位放射科医师采用双盲法分别测量两组图像上门静脉左支、右支和肝实质的CT值及图像噪声,对两位观察者的测量结果采用组内一致性系数(ICC)进行分析;采用较高年资观察者的测量结果,计算门静脉的对比噪声比(CNR),并对两组的测量结果及CNR值分别行t检验;经图像后处理,分别获得两组图像的VR和MIP重组图像并进行图像质量的主观评分,对2位医师的图像质量评分采用Kappa检验,并采用较高年资观察者的评分结果和秩和检验法对2组间的图像质量进行比较。结果:B组中门静脉最佳CNR单能量图像的能量水平集中在50KeV左右。两位观察者测量数据的一致性较好(ICC0.75)。A组中门静脉左支、门静脉右支和肝实质的CT值及背景噪声(SD值)分别为(178.38±27.25)、(174.78±24.66)、(116.13±17.01)和(32.78±4.72)HU,B组分别为(334.01±58.74)、(328.51±55.78)、(187.89±32.23)和(39.12±10.05)HU,这4个测量指标在两组间的差异均有统计学意义(P0.05)。B组中门静脉左、右支与肝实质的CNR(分别为4.08±1.90和3.93±1.80)均高于A组(分别为1.92±0.68和1.80±0.59),两组间差异有统计学意义(P均0.01)。两位医师对重组图像的主观评价结果一致性较好(A组Kappa值为0.900,B组Kappa值为0.902);两组的图像质量评分分别为3.26±0.50和3.23±0.43,差异无统计学意义(P=0.896)。结论:能谱CT能提供多组单能量图像,且在降低对比剂浓度的前提下,GSI最佳CNR单能量图像能显著提高门静脉与肝实质的对比噪声比,很好地显示门静脉及其分支。
[Abstract]:Objective: to evaluate the value of the best contrast noise ratio (CNR) single energy image of gem CT energy spectrum imaging in improving the quality of portal vein imaging with low concentration contrast agent. Methods: 136 patients who met the inclusion criteria were randomly divided into two groups: group A, treated with high concentration contrast agent (350mg I/100mL) and conventional CT scan (1.25mm slice thickness), group B using low concentration contrast agent (270mg I/100mL) and gem CT spectrum imaging (GSI). The CT values and image noise of left portal vein, right branch and hepatic parenchyma were measured by double blind method by two radiologists. The results of the two observers were analyzed by intra-group consistency coefficient (ICC). The contrast noise ratio (CNR),) of portal vein was calculated by using the measurement results of older observers, and the measurement results and CNR values of the two groups were tested by t test respectively. The VR and MIP images of the two groups of images were obtained and the subjective score of image quality was evaluated. The image quality scores of the two doctors were evaluated by Kappa test. The image quality of the two groups was compared by rank sum test. Results in group B, the energy level of the best single energy CNR image of portal vein was about 50KeV. There was good consistency between the two observers' measurements (ICC0.75.). Group A: left portal vein, The CT value and background noise (SD) of right portal vein and hepatic parenchyma were (178.38 卤27.25), (174.78 卤24.66), (116.13 卤17.01) and (32.78 卤4.72) HU,B, respectively, which were (334.01 卤58.74), (328.51 卤55.78), (187.89 卤32.23) and (39.12 卤10.05) HU,. The CNR of right branch and hepatic parenchyma (4.08 卤1.90 and 3.93 卤1.80) were higher than that of group A (1.92 卤0.68 and 1.80 卤0.59, respectively). The results of subjective evaluation of the reconstructed images by the two doctors were consistent (Kappa value was 0.900 Kappa value was 0.902 in group A), and the image quality scores of the two groups were 3.26 卤0.50 and 3.23 卤0.43, respectively, with no significant difference (P0. 896). Conclusion: energy dispersive CT can provide multiple groups of single energy images, and the optimal CNR single energy image can significantly improve the contrast noise ratio between portal vein and hepatic parenchyma, and show the portal vein and its branches well.
【作者单位】：大连医科大学附属第一医院放射科;
【分类号】：R575;R816.5

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