双能量CT线性融合技术在胰周血管成像中的应用:最佳权重因子的选择  

Application of dual-energy CT angiography with linear blending technique in peripancreatic angiography:optimal selection of weighting factor

作　　者：林志勇[1] 王慧慧[1] 刘建新[1] 王霄英[1] 

机构地区：[1]北京大学第一医院医学影像科,北京100034

出　　处：《放射学实践》2017年第8期851-855,共5页Radiologic Practice

摘　　要：目的:在双能量CT胰腺成像中采用线性融合技术进行图像重建,比较不同权重因子(M)重建图像上胰周血管的显示情况,以提高胰腺CT成像质量。方法:对38例怀疑胰腺占位的患者行双能量CT增强扫描(80kVp/Sn140kVp),采用11种权重因子(M=0~1.0,以0.1为单位递增)对动脉晚期图像进行线性融合重建。测量并比较11组图像上腹主动脉、腹腔干、肝总动脉、脾动脉、胃十二指肠动脉和肠系膜上动脉的CT值、信噪比(SNR)和对比噪声比(CNR),并由两位放射科医师对图像质量进行主观评价。结果:各支血管的SNR及CNR在11组图像间的总体差异具有统计学意义(P<0.001)。M=0.7组中的SNR最高,仅与M=0.8组间的差异无统计学意义(P>0.05)。M=0.8组中的CNR最高,仅与M=0.7组间的差异无统计学意义(P>0.05)。主观评价结果显示权重因子0.7组的图像质量最佳。结论:双能量CT胰腺增强扫描中,使用动脉晚期图像进行线性融合重建时权重因子值为0.7时胰周血管成像质量最佳。Objective：To compare the image quality of peripancreatic angiography using linear blending technique and different weighting factors in dual-energy CT scanning of pancreas, thus to improve the imaging quality of pancreas. Methods： Thirty-eight patients with suspected pancreatic mass underwent contrast enhanced dual-energy CT scan using tube voltage of 140kVp and 80kVp. Then the late-arterial phase images were postprocessed using linear blending technique with a set of 11 weighting factors （M=0 to 1.0,in steps of 0. 1）. The CT values,signal-to＇noise ratio （SNR） and contrast-to- noise ratio （CNR） of six peripancreatic vessels （abdominal aorta, celiac trunk, common hepatic artery, splenic artery, gas- troduodenal artery and superior mesenteric artery） on the 11 sets of images were measured and compared, and the subjective assessment of the image quality of the 11 sets of CTA images were made by two radiologists. Results： There were overall statistically significant differences in SNRs and CNRs of the six peripancreatic vessels among the 11 sets of images （P~ 0. 001）. For each peripancreatic vessel,SNR on images of M=0.7 was the highest,but there was no statistically significant difference between the images of M=0.8 and M：0. 7 （P〉0.05）;and CNR on images of M=0.8 was the highest,but there was no statistically significant difference between the images of M= 0.8 and M：-0.7 （P〉0.05）. For subjective as- sessment, the image quality of M= 0.7 was the best among the 11 sets of CTA images. Conclusion： In the dual-energy CT scanning of pancreas, the linear-blending images of late-arterial phase using the weighting factor of 0. 7 can provide best image quality of peripancreatic vessels.

关 键 词：胰腺 胰周血管 血管成像 双能量CT 线性融合技术 权重因子 

分 类 号：R576[医药卫生—消化系统] R816.5[医药卫生—内科学]