CARE Dose 4D技术和SAFIRE联合使用在肺结核低剂量CT检查中的应用

Application study of CARE Dose 4D technology and SAFIRE in tuberculosis by low dose CT examination

目的:通过研究CARE Dose 4D技术和SAFIRE后处理技术的联合使用在肺结核低剂量CT检查中的效果,探讨这两种新技术在胸部低剂量CT检查中的价值和意义。方法:选取我院300例继发性肺结核患者并平均分为3组,每组管电压均为120 k V,选择相同的扫描系列,然后使用SOMATOM Defination Flash CT进行胸部检查。A组启用CARE Dose 4D模式,参考管电流150 m As,后处理采用SAFIRE方式进行图像重建,SAFIRE迭代等级选择3。B组和C组不启用CARE Dose 4D模式,固定毫安秒分别使用150 m As、80 m As,重建时不使用SAFIRE而是使用FBP进行图像重建。两位影像科主治医师采用双盲法对所得图像的质量进行评价。记录相关参数及剂量指标,得到的所有数据均使用SPSS Statistics 19统计软件进行分析处理。结果:在图像主观评价方面,两位主治医师对图像质量评价有很强的一致性(Kappa=0.819)。A组的CTDIvol、DLP和ED较B组分别低约58.81%(t=20.383,P<0.05)、61.64%(t=7.894,P<0.05)、59.20%(t=15.673,P<0.05);A组的CTDIvol、DLP和ED较C组分别低约28.76%(t=12.981,P<0.05)、42.65%(t=4.762,P<0.05)、45.15%(t=11.764,P<0.05);A组的CTDIvol、DLP和ED值均低于B、C组,且差异有统计学意义。A组与B组的CT图像相比较噪声水平没有明显统计学差异(t=1.207,P>0.05),A组与C组(t=3.349,P<0.05)、B组与C组(t=2.213,P<0.05)有统计学意义。A组的信噪比均明显高于B组和C组,并且A组的对比噪声比明显高于其他两组,高于B组和C组分别约18.4%、30.88%,3组对比噪声比均具有统计学差异。结论:CARE Dose 4D技术和与SAFIRE迭代重建技术联合使用,不仅能够降低CT辐射剂量,还能保证和提高肺部组织图像质量。

Objective： By studying the CARE Dose 4D technology combined use of SAFIRE technology in tuberculosis with low dose CT scan, to evaluate the value and significance of these two kinds of new technologies. Methods： All of 300 patients with secondary pulmonary tuberculosis were distributed into three groups, each group of tube voltage was 120 kV. All groups underwent SOMATOM Definition Flash CT scanning with the same series thorax routine（adult）. Group A was enabled CARE Dose 4D mode with the reference tube current of 150 mAs, by using SAFIRE grade 3 for image reconstruction. Group B and group C were not enabled CARE dosed 4D mode, fixed mAs instead, respectively 150 mAs and 80 mAs. SAFIRE is not used but the FBP in image reconstruction. The qualities of the images were evaluated by two imaging physicians with double blind method. Record relevant parameters and dose indexes. All data were recorded and analyzed by using Statistics SPSS 19 statistical software. Results： In the subjective evaluation of image, consistency of the image quality evaluation of two physicians was very good（Kappa=0.819）. In radiation dose contrast, compared with group B, The CTDIvol, DLP and ED of group A were low about 58.81%（t=20.383, P〈0.05）, 61.64%（t=7.894, P〈0.05）, 59.20（t=15.673, P〈0.05）. Compared with group C, The CTDIvol, DLP and ED of group A were low about 28.76%（t=12.981, P〈0.05）, 42.65%（t=4.762, P〈0.05）, 45.15%（t=11.764, P〈0.05）. The CTDIvol, DLP and ED values in group A were lower than group B and C, and the difference was significant statistically, The image quality of group C was obviously different from group A and group B. Compared the CT image noise level of group A and group B, there was no significant statistical difference（t=1.207, P〉1.207）. group A and group C（t=3.349, P〈3.349）, group B and group C（t=2.213, P〈2.213） were statistically significant either. The signal to noise ratio of group A was substantially higher than that of group B and group C, and the contrast noise ratio was remarkably higher than the other two groups, higher than group B and group C were about 18.4% and 30.88%. The three groups were statistically significant. Conclusion： Combined use of CARE Dose 4D technology and Sinogram Affirmed iterative reconstruction technology, it can not only reduce the dose of CT radiation, but also ensure and improve the quality of imaging.