光子探测器双源CT大螺距扫描在腰椎外伤检查中的应用

The application of Stellar detector dual-source CT with high-pitch in lumbar injury

目的:探讨光子探测器双源CT大螺距扫描在腰椎外伤检查中的可行性。方法:前瞻性将60例腰椎外伤患者根据就诊顺序随机分为常规扫描组和大螺距组。常规检查组采用120kV、CARE Dose 4D自动mAs技术,螺距0.8,转速1.0s/r进行扫描;大螺距组采用螺距3.0,转速0.28s/r进行扫描,其它扫描条件与常规扫描组相同。记录每次扫描的放射容积CT剂量指数(CTDIvol)、剂量长度乘积(DLP)、有效剂量(ED)。对图像进行主观质量评分,并测量其客观量化噪声值。结果:常规扫描组与大螺距组有效剂量分别为(4.1±1.3)mSv、(2.8±1.1)mSv,大螺距组有效剂量较常规扫描组降低了31.7%。两组可诊断的病例数没有明显差异(常规扫描组占96.7%,大螺距组占93.3%)。常规扫描组骨窗和软组织窗SD分别为79.9±20.0、13.8±1.8,SNR分别为2.2±0.9、6.07±0.7;大螺距组骨窗和软组织窗SD分别为73.2±9.7、14.3±1.4,SNR分别为2.0±0.8、5.3±0.5,两组间差异均无统计学意义(P>0.05)。结论:光子探测器双源CT大螺距扫描在腰椎外伤检查中可以显著减少辐射剂量,图像质量能满足临床的诊断要求。

Objective：To study the possibility of Stellar detector dual-source CT with high-pitch scan in lumbar trauma.Methods：60 patients with lumbar trauma were included in this study and prospectively divided into conventional scan group and high-pitch group according to the time of visit.Scan parameters of conventional scan group were 120 kV,CARE Dose 4 D,0.8 pitch,1.0 s/r rotation rate.Parameters of high-pitch group had two alternations of 3.0 pitch and 0.28 s/r rotation rate;the others were kept the same.The volume CT dose index（CTDIvol）,dose-length product（DLP）and effective dose（ED）were recorded respectively with each group.The subjective quality grade and the objective noise of all images were recorded and analysed statistically.Results：The ED of the large-pitch group was（2.8±1.1）mSv that was 31.7%lower than that of conventional dose group（4.1±1.3）mSv.Results of subjective image quality assessment showed that there was no significant difference in the number of images that could be used for diagnosing between the two groups（conventional group96.7% and large-pitch group 93.3%）.Results of objective image quality assessment were listed as follows：In the conventional group,The SD of bone windows and soft tissue windows were 79.9±20.0 and 13.8±1.8,respectively.The SNR were 2.2±0.9 and 6.07±0.7,respectively.In the large-pitch group,the SD of bone windows and soft tissue windows were 73.2±9.7 and 14.3±1.4,respectively,and the SNR were 2.0±0.8 and 5.3±0.5.There was no significant difference between the two groups（P〈0.05）.Conclusion：Stellar detector dual-source CT with high-pitch scan can obviously reduce the radiation dose in the lumbar trauma examination.The image quality can meet the requirements for clinical diagnosis.