利用双低扫描方案进行仿真模体血管成像的可行性研究

摘要

目的：探讨利用低管电压结合自适应统计性迭代重建（adaptive statistical iterative reconstruction ，ASIR）扫描方案来降低仿真模体模拟血管成像的辐射剂量以及碘对比剂浓度的可行性。方法对固定在 CDP‐2标准仿真女性模体中2支相同的模拟血管分别注入浓度为27mg／ml 、35mg／ml 碘对比剂，并采用 NI6、NI7、NI8、NI9、NI10、NI11、NI12、NI13、NI14、NI15十个噪声指数分别进行80Kvp 、120Kvp 两组扫描，80Kvp 组采用50％ ASIR 重建，120Kvp 组采用滤过反投影法（filtered back projection ，FBP）重建。比较两组的 CT 剂量指数（volume CT dose index ，CTDIVOL ）、对比噪声比（contrast noise ratio ，CNR）、信噪比（signal noise ratio ，SNR）、CT 值及质量主观评分。结果①80Kvp 组和120Kvp 组CTDIVOL 分别为（3．818±2．44）mGy 、（5．143±3．23）mGy ，两组间差异具有统计学意义（ P值为0．001）；②27mg／ml 模拟血管80Kvp 组和27mg／ml 模拟血管120Kvp 组的 CNR 、SNR 、CT 值、图像质量主观评分差异均有统计学意义（ P 值分别为0．004、0．019、0．000和0．029）；35mg／ml 模拟血管80Kvp 组和35mg／ml 模拟血管120Kvp 组的 CNR 、SNR 、CT 值、图像质量主观评分差异均有统计学意义（ P 值分别为0．001、0．005、0．000和0．021）；③浓度27mg／ml 80Kvp 组与浓度35mg／ml 120Kvp 组 CT 值和图像质量主观评分差异具有统计学意义（ P值为0．000、0．031），CNR 、SNR 差异没有统计学意义（ P值为0．917、0．585）。结论应用低管电压结合 ASIR 重建、低浓度对比剂扫描方案可以在保证仿真模体模拟血管成像图像质量的同时，有效的降低辐射剂量。%Objective To investigate the feasibility of reducing radiation dose and contrast agent concentration of simula‐tion model simulation vessel imaging using low‐kVp with ASIR scanning mode .Methods The 2 same simulated blood vessel were fixed in the CDP‐2 simulation model ,injection of iodine contrast agent of different concentration respectively (27 mg/ml ,35 mg/ml) .Two scanning groups in the same scanning range to the simulation model were scanned using 80 Kvp and 120 Kvp separately in different noise index (NI = 6 ~ 15 ,step = 1) .50% ASIR reconstruction mode was used for the 80 kvp group ,and FBP reconstruction mode was used for the 120 Kvp group .The CTDIVOL ,CNR ,SNR ,CT value and score of image quality were compared .Results ① CTDIvol were (3 .818 ± 2 .44) ,(5 .143 ± 3 .23) for group 80 Kvp and 120 Kvp ,80 Kvp group and 120 Kvp group had significance differences ( P < 0 .001) ; ② The CNR ,SNR ,CT value , score of image quality in 27 mg/ml 80 Kvp group and 27 mg /ml 120 Kvp group had significant differences ( P = 0 .004 ,P= 0 .019 ,P = 0 .000 ,P = 0 .029) ;The CNR ,SNR ,CT value ,score of image quality in 35 mg/ml 80 Kvp group and 35 mg/ml 120 Kvp group had significant differences ( P = 0 .001 ,P = 0 .005 ,P = 0 .000 ,P = 0 .021) ; ③ The CT value , score of image quality in 27 mg/ml 80 Kvp group and 35 mg /ml 120 Kvp group had significant differences ( P = 0 .000 ,P= 0 .031) ;The CNR ,SNR in 27 mg/ml 80 Kvp group and 35 mg/ml 120 Kvp group had no significant differences ( P =0 .917 ,P = 0 .585) .Conclusion The low‐concentration contrast agent ,low‐kVp with ASIR scanning mode can improve image quality at lower radiation dose .