双源CT大螺距、CARE kV联合自适应统计迭代重建技术在腰椎外伤检查中图像质量及辐射剂量研究

Image quality and radiation dose of dual-source CT with large pitch and CARE kV combined adaptive statistical iterative reconstruction in CT scanning for lumbar injury

目的探讨双源CT大螺距、CARE kV扫描联合自适应统计迭代重建技术在腰椎外伤检查中图像质量及辐射剂量。方法选择90例行CT检查的腰椎外伤患者,其中男性57例,女性33例;年龄18～76岁,平均年龄46岁。根据患者就诊顺序随机分为3组:常规扫描组(组1)、大螺距+自适应统计迭代重建组(组2)及CARE kV+自适应统计迭代重建组(组3),每组30例。组1男性17例,女性13例;年龄23～71岁,平均年龄44.6岁。组2男性18例,女性12例;年龄18～67岁,平均年龄42.5岁。组3男性16例,女性14例;年龄25～76岁,平均年龄45.3岁。分别对3组图像进行主观图像质量评分及客观评估测量图像CT值和噪声[即标准差(SD)],计算图像信噪比(SNR)。结果 3组有效剂量(ED)分别为(3.9±1.4) mSv、(2.7±1.2) mSv、(2.5±1.1) mSv;组2、组3 ED均显著低于组1(P <0.01),组2、组3 ED较组1分别降低了30.8%、35.9%。主观图像评分,3组间图像质量评分差异无统计学意义(F=1.264,P> 0.05)。客观图像质量评估,骨窗上3组SNR分别为(2.1±0.9)、(2.0±0.4)、(2.3±0.7)(F=1.052,P> 0.05);软组织窗上3组SNR分别为(5.7±0.7)、(5.3±0.5)、(6.2±1.4)(F=1.081,P> 0.05),3组间骨窗及软组织窗感兴趣区SD差异亦无统计学意义(F=0.216、0.763,P>0.05)。结论双源CT大螺距、CARE kV扫描联合自适应统计迭代重建技术在腰椎外伤检查中大大降低了辐射剂量,同时可以保证图像质量能满足临床的诊断要求。

Objective To explore the image quality and radiation dose of dual-source CT with large pitch and CARE kV combined adaptive statistical iterative reconstruction for lumbar injury. Methods A total of 90 patients with lumbar injury were enrolled, which included 57 males and 33 females;aged 18-76 years old with mean age of 46 years old. According to treatment order, all patients were randomly divided into 3 groups(n = 30): conventional group(group 1, included 17 males and 13 females;aged 23-71 years old with mean age of 44.6 years old), large pitch + adaptive statistical iterative reconstruction group(group2, included 18 males and 12 females;aged 18-67 years old with mean age of 42.5 years old) and CARE kV + adaptive statistical iterative reconstruction group(group 3, included 16 males and 14 females;aged 25-76 years old with mean age of45.3 years old). The subjective quality grade and objective CT value and noise[standard deviation(SD)] of images from 3 groups were recorded, then image signal to noise ratio(SNR) were calculated. Results The effective doses(ED) of 3 groups were(3.9 ±1.4) m Sv,(2.7 ± 1.2) mSv and(2.5 ± 1.1) mSv, and ED of group 2 and group 3 were significantly lower than that of group 1(P < 0.01).Compared with group 1, the ED of group 2 was reduced by 30.8 % and group 3 reducedby 35.9 %. For subjective image quality assessment, there was no significant difference in 3 groups(F = 1.264, P > 0.05). For objective image quality assessment, the SNR of 3 groups in bone window was(2.1 ± 0.9),(2.0 ± 0.4) and(2.3 ± 0.7)(F = 1.052, P > 0.05);in soft tissue window was(5.7 ± 0.7),(5.3 ± 0.5) and(6.2 ± 1.4)(F = 1.081, P > 0.05), and there were no significant differences of bone window and soft tissue window in SD of 3 groups(F = 0.216, 0.763, P > 0.05). Conclusion It is demonstrated that the dual-source CT large pitch and CARE kV scanning combined adaptive statistical iterative reconstruction technique could greatly reduce the radiation dose in lumbar spine injury examination, and ensure the quality of image meet the clinical diagnostic requirements.