能谱CT单能量成像在去除肝癌经导管动脉化疗栓塞术治疗后碘油硬化伪影的应用

Monochromatic Imaging of Spectral CT for Reducing the Artifacts from Lipiodol After Transcatheter Arterial Chemoembolization of Hepatocellular Carcinoma

目的探讨能谱CT在去除肝癌经导管动脉化疗栓塞术（TACE）治疗后碘油硬化伪影的应用价值,寻求图像质量最佳的单能量成像点。资料与方法回顾性分析23例肝癌TACE治疗后行能谱CT检查患者的图像。采用能谱软件处理后可获得Mono图像（40-140 keV,间隔10 keV）和QC图像（140 kVp）。对11组Mono图像进行主观评分,并对其结果进行优化。选取主观评分较高的Mono图像及QC图像,测量伪影最多层面感兴趣区的CT值（ROI1）、同层面无伪影或伪影较少感兴趣区的CT值（ROI2）,比较两者CT值的差异。计算并比较去除伪影最佳的Mono图像及QC图像的信噪比（SNR）。结果 70-120 ke V时Mono图像的主观评分较高;110 keV Mono图像的ROI1为（60.18±12.48）HU,ROI2为（60.89±12.12）HU,差异无统计学意义（P〉0.05）,其余5组Mono图像及混合能量图像的ROI1、ROI2比较,差异有统计学意义（P〈0.05）。110 ke V Mono图像的SNR为8.47±1.59,QC图像的SNR为7.31±1.24,两者差异无统计学意义（P〉0.05）。结论选择能谱CT110 keV的Mono图像可以在不影响整体图像质量的前提下有效去除肝癌TACE治疗后碘油的硬化伪影。

Purpose To investigate the application of spectral CT in reducing the artifacts of lipiodol in hepatocellular carcinoma after transcatheter arterial chemoembolization（TACE） treatment, and to find the best monochromatic imaging parameters. Materials and Methods The images of 23 patients with hepatocellular carcinoma treated by TACE who received GSI examination were analyzed retrospectively. The spectral analysis was used to obtain monochromatic images（with energy ranging from 40 keV to 140 keV in 10 keV increments） and quality controlled images（with 140 kVp）. The subjective score of 11 groups of Mono images and the results were optimized. The Mono images with higher subjective scores and the QC images were selected. The CT value of the region of interest in the measurement of the level with the most artifacts was marked as ROI1. The CT value of the same image with no or less artifacts was also measured and marked as ROI2. Paired t test was used to determine the CT value. The signal-to-noise ratio of the best Mono images and the QC images were measured. The result was compared using independent sample t test. Results The Mono images with 70-120 keV had a higher score. In the Mono images with 110 keV, there was no significant difference between the CT value of ROI1 and ROI2 [（60.18±12.48） HU vs.（60.89±12.12） HU, t=- 2.67, P〈0.05]. The CT value of ROI1 and ROI2 in the other 5 groups of Mono images and the QC images were significantly different（P〉0.05）. The signal-to-noise ratio of Mono images with 110 keV was 8.47±1.59. The SNR of QC images was 7.31±1.24. There was no significant difference between the two groups（P〈0.05）. Conclusion The Mono images with 110 keV can effectively reduce the artifacts of lipiodol after treatment with TACE without image quality loss.