多模型迭代重建在CT门静脉成像中改善图像质量的应用

目的:探讨多模型迭代重建（ASIR-V）在CT门静脉成像（CTPV）中改善图像质量的应用价值。方法:收集Revolution CT检查CTPV患者60例并随机分为A、B组。两组均采用管电压120 kV、噪声指数10、对比剂用量450 mgI/kg。扫描结束后，A组采用40%ASIR，B组采用40%ASIR-V。分别测量门静脉主干、门静脉左支、门静脉右支的CT值和CT值标准差，并计算信噪比和对比噪声比。记录两组患者CT容积剂量指数（CTDIVOL）、剂量长度乘积（DLP），并计算有效辐射剂量（ED）。由两名有经验放射科医师采用5分法标准对图像质量进行双盲法主观评分。结果:两组患者一般资料、辐射剂量（CTDIVOL、DLP、ED）和对比剂总量间差异无统计学意义（P>0.05）。两组门静脉主干、门静脉左支及右支CT值均无统计学差异（P>0.05）。A组门静脉主干、门静脉左支及右支CT值的标准差高于B组，A组信噪比和对比噪声比低于B组，且差异均具有统计学意义（P<0.05）。两名医师对两组图像主观评分具有很好的一致性（Kappa值>0.75, P<0.05），B组图像主观评分显著高于A组（P<0.05）。结论:ASIR-V可以显著提高门静脉图像质量，为临床诊断提供更好的CTPV图像。

Application of adaptive statistical iterative reconstruction-V technique in CT portal venography for improving image quality

Abstract: Objective To explore the application value of adaptive statistical iterative reconstruction-V (ASIR-V) technique in improving the quality of computed tomography portal venography (CTPV) image. Methods Sixty patients who underwent CTPV using Revolution CT were enrolled and randomly divided into group A and group B. Tube voltage of 120 kV, noise index of 10 and contrast agent dose of 450 mgI/kg were adopted in both two groups. After scanning, group A was reconstructed with 40%ASIR, while group B was reconstructed with 40%ASIR-V. The CT values and its standard deviations of the main portal vein (MPV), the left branch of portal vein (LPV), and the right branch of portal vein (RPV) were measured, and their signal-to-noise ratios (SNR) and contrast-to-noise ratios (CNR) were calculated. The volume CT dose index (CTDIVOL) and dose length product (DLP) in two groups were recorded, and the effective dose (ED) was calculated. The subjective scores of image quality were assessed blindly by two experienced radiologists using a 5-point system. Results There was no significant difference between two groups in general information, irradiation dose (CTDIVOL, DLP, ED) and the total contrast agent dose (P>0.05). The CT values of MPV, LPV and RPV showed no statistical difference between two groups (P>0.05). Moreover, compared with group B, group A had higher standard deviations of CT values and lower SNR and CNR for MPV, LPV and RPV, with statistical significance (P<0.05). There was a good agreement between two radiologists (Kappa>0.75, P<0.05). The subjective score of the images in group B was significantly higher than that in group A (P>0.05). Conclusion ASIR-V technique can significantly improve the quality of CTPV image, thereby providing better CTPV image for clinical diagnosis.