ISSN 1004-4140
CN 11-3017/P

对比剂分次团注联合能量成像获得CTU和CTA联合成像的应用研究

Study on the Application of CTU and CTA Combined Imaging by Fractional Injection Combined of a Contrast Agent with Energy Imaging

  • 摘要: 目的:探讨对比剂分次团注结合双层探测器光谱CT 50 keV虚拟单能量图像(VMI),在CT泌尿系成像(CTU)与主动脉CTA联合成像中的应用价值。方法:收集2024年3月至4月在首都医科大学附属北京同仁医院Philips IQon双层探测器光谱CT行CTU检查患者32例为试验组。使用对比剂分次团注及团注追踪技术;扫描后重建常规120 kVp混合能量图像为A1组;光谱重建获得50 keV VMI为A2组。收集2023年12月至2024年3月间在相同设备行CTU检查患者32例为对照组,使用对比剂分离团注技术及团注追踪技术;扫描后重建常规120 kVp混合能量图像为B组。客观评价包括:比较3组腹主动脉、双侧肾动脉的CT值、对比噪声比(CNR)、信噪比(SNR);比较输尿管起始部平均CT值和中下部平均CT值,并采用Kruskal-Wallis检验,采用Nemenyi检验进行两两比较。试验组与对照组的有效辐射剂量比较采用Wilcoxon检验。主观评价由两名高年资影像医师分别对3组CTA及CTU图像进行4分法和3分法评价,两名医师主观评分的一致性采用Kappa检验。结果:客观评价指标中,A2组分别与A1组和B组比较,均有统计学差异;A1组与B组仅双侧肾动脉SNR有统计学差异。两组有效辐射剂量有统计学差异,试验组较对照组降低15.1%。3组CTA、CTU图像主观评价无统计学差异;两名医师对CTA图像评分结果一致性非常好,对CTU图像评分结果一致性好。结论:利用对比剂分次团注行CTU检查时,获得泌尿系及主动脉同时显影的融合图像,不仅具有明确的解剖关系及相同的图像质量,而且降低有效辐射剂量;光谱重建获得的50 keV虚拟单能量图像,优化CTU及CTA图像质量,具有临床价值。

     

    Abstract: Objective: This study aimed to investigate the application value of fractional bolus injection of a contrast agent combined with double-layer detector spectral CT 50 keV virtual monoenergetic imaging (VMI) in combined imaging of computed tomography urography (CTU) and aortic CT angiography (CTA). Methods: The experimental group included 32 patients who underwent spectral CTU with a Philips IQon dual-layer detector at Beijing Tongren Hospital, Capital Medical University, between March and April 2024. Using fractional bolus injection of a contrast agent and bolus tracking technology, the conventional 120 kVp mixed energy image was reconstructed after scanning for group A1; the 50 keV VMI obtained by spectral reconstruction was group A2. The control group included 32 patients who underwent CTU examination between December 2023 and March 2024 using the same equipment, and the contrast agent split bolus and group injection tracking techniques were used. After scanning, the conventional 120 kVp mixed energy image was reconstructed for group B. The objective evaluation included the CT value, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) of the abdominal aorta and bilateral renal arteries, which were compared among the three groups. The Kruskal–Wallis and Nemenyi tests were used to compare the average CT values of the initial, middle, and lower parts of the ureter. Wilcoxon test was used to compare the effective radiation dose between the experimental and control groups. Subjective evaluation was performed by two senior radiologists on the three groups of CTU and CTA images using the 4- and 3-point methods, respectively. The consistency of the subjective scores of the two radiologists was analyzed using the Kappa test. Results: Among the objective evaluation indices, there were statistically significant differences among groups A2, A1, and B. There was a significant difference in the SNR of the bilateral renal arteries between groups A1 and B. The effective radiation dose of the experimental group was 15.1% lower than that of the control group, which was significantly different. There was no significant difference in the subjective evaluation of the CTA and CTU images among the three groups. The consistency of the CTA and CTU image scoring results between the two physicians was excellent and good, respectively. Conclusion: If CTU examination was performed by fractional injection of a contrast agent, fusion images of the urinary system and aorta were obtained, which not only had a clear anatomical relationship and the same image quality, but also reduced the effective radiation dose. The 50keV virtual monoenergetic image obtained by spectral reconstruction optimizes the image quality of CTU and CTA and has clinical value.

     

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