基于原始数据域迭代重建技术在颞骨高分辨率CT中的应用

Application of Sinogram-affirmed Iterative Reconstruction in Routine Dose Temporal Bone High Resolution CT

目的探讨滤波反投影（FBP）与基于原始数据迭代（SAFIRE）重建对常规剂量颞骨高分辨率CT（HRCT）图像质量的影响,为实现低剂量扫描提供参考。资料与方法 60例行颞骨HRCT患者行常规剂量扫描,分别进行FBP及SAFIRE（strength 1-5）重建,比较6组图像的平均CT值、噪声（SD）、信噪比（SNR）、对比噪声比（CNR）、主观评分及病变检出情况。结果 6组图像平均CT值差异无统计学意义（P〉0.05）;与FBP比较,SAFIRE（strength 1-5）重建SD逐渐下降（F=1.78,P〈0.05）,分别降低23.1%、39.2%、42.4%、54.1%、61.2%;SNR、CNR逐渐升高（F=1.42、3.15,P〈0.05）,SNR分别提高26.6%、40.0%、71.1%、117.7%、153.3%,CNR分别提高17.4%、33.1%、63.2%、104.1%、147.2%。6组图像主观评分差异有统计学意义（P〈0.05）,SAFIRE 2-4较FBP、SAFIRE 1、5评分高,SAFIRE 2-4组间差异无统计学意义（P〉0.05）,SAFIRE 3重建细腻度、边缘锐利度较好,主观评分最高。结论颞骨HRCT常规剂量扫描结合SAFIRE迭代重建技术,能有效提高图像质量,具有潜在的降低辐射剂量的作用。

PurposeTo evaluate the impact of filtered back-projection （FBP） and sinogram-affirmed iterative reconstruction （SAFIRE） technique on the image quality of routine dose temporal bone high resolution CT （HRCT） scan, and to provide reference for the realization of low dose scanning.Materials and Methods Sixty patients underwent routine dose temporal bone HRCT scan, 6 groups of images were reconstructed with FBP and SAFIRE （strength grade 1-5）, average CT value, noise （SD）, signal to noise ratio （SNR）, contrast to noise ratio （CNR）, subjective score and lesion detection were compared between different groups.Results There was no significant difference of average CT value among the 6 groups （P〉0.05）; compared with FBP, SD of SAFIRE （strength 1-5） reconstruction decreased gradually （F=1.78,P〈0.01）, which was 23.1%, 39.2%, 42.4%, 54.1% and 61.2% respectively; SNR and CNR increased gradually （F=1.42 and 3.15, P〈0.05）, SNR increased 26.6%, 40%, 71.1%, 117.7% and 153.3% respectively, while CNR increased 17.4%, 33.1%, 63.2%, 104.1% and 147.2% respectively. The differences among the 6 groups were statistically significant （P〈0.05）, subjective scores of SAFIRE 2-4 were higher than those of FBP, SAFIRE 1 and SAFIRE 5 group, while the difference among SAFIRE 2-4 group was statistically insignificant, reconstruction smoothness and edge sharpness of SAFIRE 3 group was better, with highest objective score.Conclusion Routine dose temporal bone HRCT scan combined with SAFIRE reconstruction can increase the image quality of temporal bone high resolution scan effectively, with the potential for radiation dose reduction.