PET贝叶斯惩罚似然法对单发肺占位诊断的增益价值

Added value of PET Bayesian penalized likelihood reconstruction algorithm in the diagnosis of solitary pulmonary nodules/masses

目的对比传统光电倍增管(PMT)及有序子集最大期望值迭代法(OSEM), 探究硅光电倍增管(SiPM)及贝叶斯惩罚似然法(BPL)对单发肺占位18F-FDG PET半定量参数及临床诊断效能的影响。方法前瞻性收集2020年3月至2022年1月间山西医科大学第一医院初诊为单发肺内结节和(或)肿块的患者[118例;男76例、女42例, 年龄(63.0±10.1)岁], 先后在不同PET/CT设备上行胸部显像, 根据采集及重建方法的不同分为PMT+OSEM、SiPM+OSEM和SiPM+BPL 3组。测量肺占位的SUVmax、SUVmean、肿瘤代谢体积(MTV)及病灶糖酵解总量(TLG)等指标, 并计算得到信噪比(SNR)及信号本底比(SBR)。采用单因素方差分析和Kruskal-Wallis秩和检验比较各组间参数的差异, 采用ROC曲线测定各组SUVmax鉴别良恶性病灶的最佳界值及AUC。结果 118例患者中, 恶性结节83个, 良性结节35个。SiPM+BPL组图像质量[(4.23±0.64)分]优于SiPM+OSEM[(3.57±0.50)分]和PMT+OSEM组[(3.58±0.51)分;F=54.85, P<0.001]。SiPM+BPL和SiPM+OSEM组结节的SUVmax[7.57(3.86, 15.61)和4.95(2.22, 10.48)]、SUVmean[4.43(2.28, 9.12)和2.84(1.21, 5.71)]、MTV[3.54(1.57, 7.67)和5.09(2.83, 11.79) ml]、SNR[28.12(12.55, 54.38)和20.16(8.29, 41.45)]及SBR[4.03(1.83, 7.75)和2.32(0.96, 5.03)]的差异均有统计学意义(H值:16.63~37.05, 均P<0.001)。SiPM+BPL、SiPM+OSEM及PMT+OSEM对<2 cm肺结节的良恶性鉴别SUVmax最佳界值为3.31、2.21及2.05, AUC分别为0.686、0.689、0.615;而对≥2 cm的结节和(或)肿块则为10.29、6.49及4.33, AUC分别为0.775、0.782、0.774。结论图像质量及肺占位各半定量参数主要受重建算法的影响, BPL能提高肺结节的SUVmax、SUVmean、SBR及SNR, 降低MTV, 而对肝本底无明显影响。SiPM+BPL较SiPM+OSEM及PMT+OSEM对孤立性肺占位良恶性鉴别诊断的SUVmax最佳界值提高。

Objective To investigate the effects of silicon photomutipliers(SiPM)detector and Bayesian penalized likelihood(BPL)reconstruction algorithm on semiquantitative parameters of ^(18)F-FDG PET/CT and diagnostic efficiency for solitary pulmonary nodules/masses compared with traditional photomultiplier tube(PMT)and ordered subsets expectation maximization(OSEM).Methods From March 2020 to January 2022,118 patients(76 males,42 females,age(63.0±10.1)years)newly diagnosed with solitary pulmonary nodules/masses in First Hospital of Shanxi Medical University were prospectively enrolled and underwent ^(18)F-FDG PET/CT imaging with two different PET/CT scanners successively.The images were divided into PMT+OSEM,SiPM+OSEM and SiPM+BPL groups according to PET detector and reconstruction algorithms.The SUVmax,SUVmean,metabolic tumor volume(MTV)and total lesion glycolysis(TLG)of pulmonary nodules/masses were measured,then signal-to-noise ratio(SNR)and signal-to-background ratio(SBR)were calculated.One-way analysis of variance and Kruskal-Wallis rank sum test were performed to compare differences of above parameters among groups.ROC curve analysis was used to analyze the optimal threshold of SUVmax for the differential diagnosis of pulmonary nodules/masses and AUCs were obtained.Results There were 83 malignant nodules and 35 benign nodules.The image quality of SiPM+BPL group(4.23±0.64)was better than that of SiPM+OSEM group(3.57±0.50)or PMT+OSEM group(3.58±0.51;F=54.85,P<0.001).There were significant differences in SUVmax(7.57(3.86,15.61)vs 4.95(2.22,10.48)),SUVmean(4.43(2.28,9.12)vs 2.84(1.21,5.71)),MTV(3.54(1.57,7.67)vs 5.09(2.83,11.79)),SNR(28.12(12.55,54.38)vs 20.16(8.29,41.45))and SBR(4.03(1.83,7.75)vs 2.32(0.96,5.03))between SiPM+BPL and SiPM+OSEM groups(H values:16.63-37.05,all P<0.001).The optimal threshold values of SUVmax in SiPM+BPL,SiPM+OSEM and PMT+OSEM were 3.31,2.21,2.05 with AUCs of 0.686,0.689,0.615 for nodules<2 cm,and were 10.29,6.49,4.33 with AUCs of 0.775,0.782,0.774 for nodules/masses≥2 cm.Conclusions Image quality and parameters of pulmonary nodules/masses are mainly affected by the reconstruction algorithms.BPL can improve SUVmax,SUVmean,SBR and SNR,but reduce MTV without significant effect on liver parameters.SiPM+BPL has a higher diagnostic threshold of SUVmax than SiPM+OSEM and PMT+OSEM.