能谱CT肺动脉造影团注测试法单能量图像在降低碘摄入中的应用

Optimization of Monochromatic Imaging in Reducing Iodinated Contrast Dose in CT Pulmonary Angiography

目的比较能谱CT肺动脉造影（CTPA）团注测试法单能量图像与透视触发法常规的图像质量,以降低机体总碘摄入并优化图像质量。资料与方法 68例接受CTPA检查的患者随机分为研究组和常规组,每组34例。研究组行GSI能谱扫描,使用造影剂欧乃派克（300 mg I/ml）30 ml,使用随机软件计算最佳ke V的单能量图像。常规组行透视触发扫描,使用造影剂碘普罗胺（370 mg I/ml）80 ml,所得图像为混合能量图像。比较两组患者主肺动脉、左肺动脉干、右肺动脉干、左肺下动脉及右肺下动脉CT值,比较两组图像的对比噪声比与图像质量主观评分。结果研究组总碘摄入量（9000 mg）显著低于常规组（29 600 mg）。研究组主肺动脉、左肺动脉、右肺动脉、左下肺动脉、右下肺动脉的对比噪声比均高于常规组,差异均有统计学意义（t=2.07~2.71,P〈0.05）。2名医师评价图片的结果一致性较好（Kappa=0.8,P〈0.05）。研究组图像主观评分高于常规组,但差异无统计学意义（Z=-0.944,P〉0.05）。结论团注测试法与能谱CT单能量图像结合可显著降低机体碘摄入并优化图像质量。

Purpose To explore the feasibility of optimizing monochromatic images in reducing iodinated contrast dose in CT pulmonary angiography（CTPA）. Materials and Methods Sixty-eight patients undergoing CTPA were randomly divided into two groups, with half in research group and half in conventional group to evaluate image quality. Research group underwent spectral CT imaging with the injection of 30 ml Omnipaque（300 mg I/ml） and optimal monochromatic images were postprocessed using the software of GSI viewer. Conventional group underwent conventional CTPA with the injection of 80 ml Ultravist（370 mg I/ml）. The CT values were measured respectively in the main pulmonary artery, left pulmonary trunk, right pulmonary trunk, left lobe artery and right lobe artery. The contrast noise ratio（CNR） in two groups were calculated, and image quality were subjectively assessed. Results The total iodine intake in research group（9000 mg） was significantly lower than that of conventional group（29 600 mg）. CNR in the main pulmonary artery, left pulmonary trunk, right pulmonary trunk, left lobe artery and right lobe artery in research group was significantly higher than that of conventional group（t=2.07-2.71, P〈0.05）. Subjective image quality scores in research group were also higher than that of conventional group but had no statistical difference（Z=- 0.944, P〈0.05）, while there was a good agreement between the two readers（Kappa=0.8, P〈0.05）. Conclusion It is possible to reduce iodinated contrast dose using spectral CT imaging and improve the image quality of CTPA.