胸部低剂量CT扫描对肺部感染检查图像质量影响的研究

目的探讨胸部常规剂量与低剂量CT扫描对拟诊为肺部感染患者图像质量的影响,以优化胸部低剂量CT扫描方案。方法回顾性分析2020年1-2月于该院拟诊为肺部感染行胸部CT平扫的患者108例;以2020年2月3日为方案转换时间点,在此前为常规剂量(130kV,参考管电流为80mAs)组共48例,在此后为低剂量(110kV,参考管电流为20mAs)组共60例;两组均采用高级迭代重建算法(ADMIRE),重建层厚1mm。将数据传入MMWP4后处理工作站进行信噪比(SNR)、对比噪声比(CNR)、辐射剂量参数容积CT剂量指数(CTDIvol)、剂量长度乘积(DLP)、有效辐射剂量(ED)]测量,同时数据传入PACS进行背景噪声评分和整体图像质量评分。结果(1)客观评价显示常规剂量组的SNR和CNR(7.33±2.12,181.07±48.13)显著大于低剂量组(3.81±1.06,93.95±25.08),差异均有统计学意义(P<0.001);常规剂量组的CTDIvol、DLP、ED(6.37±1.28)mGy,(241.83±63.31)mGy·cm,(3.39±0.89)mSv]显著大于低剂量组(1.62±0.25)mGy,(63.79±10.92)mGy·cm,(0.89±0.15)mSv],差异均有统计学意义(P<0.001)。(2)主观评价显示常规剂量组对背景噪声和整体图像质量的评分(1.94±0.24)分,(4.08±0.35)分]与低剂量组(1.97±0.18)分,(3.98±0.29)分]差异无统计学意义(P>0.05)。结论胸部低剂量CT扫描技术的图像质量与常规剂量无明显差异,而辐射剂量明显降低,图像质量满足肺部感染的影像诊断要求,该方案可在临床广泛推广。

Study on influence of chest low-dose CT scan on quality of examination image for lung infection

Objective To investigate the influence of chest routine dose and low-dose CT scan on the image quality of the patients with suspeciously diagnosed lung infection for optimize the chest low-dose CT scan program.Methods One hundred and eight patients with chest CT flat scan due to suspeciuosly diagnosed lung infection in the hospital from January to February 2020 were retrospectively analyzed.February 3,2020 served as the time point of program conversion.The routine dose scan(130 kV,reference tube current 80 mAs)group(48 cases)was before this time point.The low-dose scan(110 kV,reference tube current 20 mAs)group(60 cases)was after this time point;the two groups adopted the advanced iterative reconstruction algorithm(ADMIRE),the reconstruction laver thickness was 1 mm.After the data was passed into the MMWP4 post-processing workstation for measuring the signal-to-noise ratio(SNR),contrast noise ratio(CNR),radiation dose parameters(CTDIvol,DLP,ED),meanwhile the data were also passed into PACS for conducting the background noise scoring and overall image quality scoring.Results (1)The objective evaluation showed that SNR and CNR(7.33±2.12,181.07±48.13)in the routine dose group were significantly greater than in the low dose group(3.81±1.06,93.95±25.08),and the differences were statistically significant(P<0.001);CTDIvol,DLP and ED (6.37±1.28)mGy,(241.83±63.31)mGy·cm,(3.39±0.89)mSv]in the routine dose group were significantly greater than in the low dose group (1.62±0.25)mGy,(63.79±10.92)mGy·cm,(0.89±0.15)mSv],and the differences were statistically significant(P<0.001).(2)The subjective evaluation showed that there was no statistically significant difference in the background noise and overall image quality score between the routine dose group(1.94±0.24)points,(4.08±0.35)points]and the low dose group(1.97±0.18)points,(3.98±0.29)points,P>0.05].Conclusion There is no significant difference in the image quality between the low dose and routine dose chest CT scanning technology,while the radiation dose is significantly reduced.The image quality meets the image diagnostic requirements of lung infection,and this program can be widely promoted in clinic.