能谱CT小剂量对比剂在肺动脉造影术中的应用

Preliminary application of low dose contrast agent in CTPA with spectral CT imaging

目的:探讨能谱CT小剂量对比剂在肺动脉CT血管造影(CT pulmonary angiography,CTPA)中的临床应用价值。方法:对疑似肺动脉栓塞患者52例,均行CPTA检查。依据登记单双号随机分为研究组(n=25)与对照组(n=27),其中研究组采用能谱CT检查,对比剂剂量35 ml;对照组采用64排CT普通造影检查,对比剂剂量80~90 ml。测量肺动脉主干,左、右肺动脉干,主动脉及肺静脉的CT值,并计算肺动脉的对比噪声比(contrast to noise ratio,CNR)。同时由2名资深影像医师分别独立对造影图像质量进行评价。结果:研究组肺动脉主干,左、右肺动脉干的CT值分别为(432.2±63.4)、(373.5±48.8)、(381.4±53.6)HU,CNR值为62.5±6.4,均明显高于对照组,差异有统计学意义(P<0.05)。在图像主观评价方面,研究组图像得分优于对照组,差异有统计学意义(P<0.05)。结论:能谱CT小剂量对比剂肺动脉造影可降低对比剂使用剂量,造影图像质量优于普通螺旋CT造影。

Objective To investigate the clinical application value of low dose contrast agent in computerized tomography pulmonary angiography（CTPA） with spectral CT imaging. Methods Totally 52 patients suspected with pulmonary embolism underwent multi-slice spiral CT pulmonary angiography, and were randomly divided into a control group（n =27） and a research group（n=25）. The research group used spectral CT with 35 ml of contrast medium and the control group used 64-slice CT with conventional 80 to 90 ml of contrast medium. The CT values of the pulmonary trunk, left pulmonary artery（LPA）,right pulmonary artery（RPA）, pulmonary vein and ascending aorta were measured. The contrast to noise ratio（CNR） of the pulmonary artery was also calculated. In addition, the image quality of CTPA was evaluated independently by two experienced radiologists. Results The CT values（HU） of the pulmonary trunk, left pulmonary artery（LPA）,right pulmonary artery（RPA） in the research group were（432.2±63.4）,（373.5±48.8）,（381.4±53.6） and（62.5±6.4）, respectively, and significantly higher than those in the control group, showing statistical differences（P 0.05）. The evaluation results of the CTPA images by two radiologists showed that the image quality in the research group was better than that in the control group（P0.05）. Conclusion The image quality of pulmonary angiography with spectral CT using low contrast medium dose can be improved compared with the conventional spiral CT.