不同重建矩阵对18F-FDG PET图像质量和SUV值的影响

目的:探讨不同重建矩阵对18F-FDG PET图像质量和标准摄取值(standard uptake value,SUV)的影响,以持续获得高质量的PET图像。方法:选择符合美国国家电气制造商协会标准的模体进行体模实验,选择2018年5月至2019年6月于南京市第一医院核医学科行18F-FDG PET/CT全身扫描的40例患者(共96处病灶)图像进行临床实验。对重建矩阵分别为128×128、150×150、192×192、256×256、512×512和600×600时的PET图像质量采用变异系数(coefficient of variation,CV)、对比度、信噪比及肝脏SUVmax、SUVmean、SUVSD、CVliver值和病灶SUVmax进行评估。结果:(1)不同重建矩阵所得模体PET图像微球均清晰可见,重建矩阵为192×192时,模体PET图像信噪比取得最大值,CV值取得最小值。(2)重建矩阵为192×912和256×256时,临床实例PET图像病灶清晰度和肝脏均匀度较高。不同重建矩阵所得病灶SUVmax和肝脏SUVmean差异无统计学意义(F=0.757,P=0.581;F=0.002,P>0.999),肝脏SUVmax、SUVSD和CVliver差异具有统计学意义(F=7.879、19.51、37.34,P均<0.0001)。重建矩阵为256×256时,病灶SUVmax取得最大值,且肝脏SUVmean趋于稳定。结论:18F-FDG PET图像质量和SUV值受重建矩阵影响较大,重建矩阵为256×256时可满足临床诊断需要,重建矩阵为192×192时图像质量最佳。

Influences of reconstruction matrixes on image quality and standard uptake value in 18F-FDG PET imaging

Objective To investigate the impacts of different reconstruction matrixes on image quality and standard uptake value(SUV)in 18F-FDG PET imaging so as to obtain high-quality PET images constantly.Methods The phantom experiment was executed with the phantom according with the standard of the National Electrical Manufacturers Association of America,and the clinical experiment was carried out with the images of 40 patients(96 lesions in total)undergoing whole-body scan by 18F-FDG PET in Department of Nuclear Medicine of Nanjing First Hospital from May 2018 to June 2019.The PET image quality of 128×128,150×150,192×192,256×256,512×512 and 600×600 reconstruction matrices were evaluated by using the coefficient of variation(CV),contrast,signal-to-noise ratio,the SUVmax,SUVmean,SUVSD and CVliver of the liver as well as the SUVmax of the lesions.Results(1)Four spheres were clear in the phantom PET images,and SNR achieved maximum at reconstruction matrix of 192×192,meanwhile,CV acquired the minimum.(2)The tumor definition and liver homogeneity of PET image quality with 192×192 and 256×256 outperformed the others in the clinical study.In addition,the tumor SUVmax and liver SUVmean had no significant statistical differences among the 6 reconstruction matrix groups(F=0.757,P=0.581;F=0.002,P>0.999),whereas liver SUVmax,SUVSD and CVliver for all the 6 reconstruction matrix groups were different significantly(F=7.879,F=19.51,F=37.34,all P<0.0001).Furthermore,lesion SUVmax obtained maximum at the reconstruction matrix of 256×256,and liver SUVmean became stable at the same time.Conclusion Different reconstruction matrixes have influences on 18F-FDG PET image quality and SUV,at the reconstruction matrix of 256×256 the need of clinical diagnosis can be met,and at the reconstruction matrix of 192×192 optimal PET image can be acquired.