摘要
目的 探讨飞行时间(TOF)和点扩散函数(PSF)重建对 18F-FDG PET/CT显像肺癌纵隔淋巴结转移的增益价值.资料与方法 回顾性分析2020年3月9日—2021年7月23日在佛山市第一人民医院行PET/CT检查的肺癌纵隔淋巴结转移患者68例.分别采用有序子集最大期望值迭代法(OSEM)、OSEM+TOF、OSEM+PSF、OSEM+TOF+PSF重建图像,比较不同重建算法对肺癌纵隔淋巴结转移病灶的分辨能力,以及病灶信噪比(SNR)和标准化摄取值(SUV)的差异.结果 使用OSEM+TOF+PSF重建可获得病灶 SUVmax、SUVmean和 SNR的最高值,与常规 OSEM比较分别增加了 21.99%、22.86%和60.14%(t=28.321、19.11、11.059,P均<0.01);其差异百分比在直径≤22 mm的较小病灶中明显大于直径>22 mm的较大病灶(24.1%比21.1%、25.3%比19.3%、70.6%比63.3%;Z=-3.658、-4.313、-2.154,P均<0.05),在SNR≤15.31的低对比度病灶中明显大于SNR>15.31 的高对比度病灶(23.6%比 21.4%、25.3%比 21.1%、85.7%比 46.0%;Z=-3.519、-2.336、-5.106,P均<0.05);在不同重建算法的病灶可检测性评价结果中,OSEM+TOF+PSF图像对纵隔淋巴结转移病灶的显示最清晰,其中87.4%的病灶为明确存在,显著高于OSEM图像的73.1%(χ2=11.704,P=0.001),但OSEM+PSF图像中病灶明确存在的比例与OSEM比较并未显著增加(73.1%比75.8%;χ2=0.361,P=0.548).结论 TOF和PSF结合能显著提高肺癌纵隔淋巴结转移病灶的探测能力,以及病灶SNR和SUV,尤其在小病灶和低对比度病灶中更为显著.
Abstract
Purpose To evaluate the added value of time of flight(TOF)and point spread dispersion(PSF)reconstruction in mediastinal lymph node metastasis of lung cancer in 18F-FDG PET/CT imaging.Materials and Methods Sixty-eight lung cancer patients with mediastinal lymph node metastasis who underwent PET/CT examination in the First People's Hospital of Foshan from March 9,2020 to July 23,2021 were analyzed retrospectively.The different methods,including ordered subsets estimation maximization(OSEM),OSEM+TOF,OSEM+PSF,OSEM+TOF+PSF,were used to reconstruct the images.The resolution of different reconstruction algorithms for mediastinal lymph node metastasis of lung cancer,as well as the differences of signal-to-noise ratio(SNR)and standard uptake value(SUV)were compared,respectively.Results The highest values of SUVmean,SUVmax and SNR were obtained via OSEM+TOF+PSF method,which increased by 21.99%,22.86%and 60.14%,compared with conventional OSEM method(t=28.321,19.11,11.059,all P<0.01).The difference percentage in smaller lesions that diameter≤22 mm was significantly higher than that in larger lesions that diameter>22 mm(24.1%vs.21.1%,25.3%vs.19.3%,70.6%vs.63.3%;Z=-3.658,-4.313,-2.154,all P<0.05),and the difference percentage in low contrast lesions that SNR≤15.31 was significantly higher than that in high contrast lesions that SNR>15.31(23.6%vs.21.4%,25.3%vs.21.1%,85.7%vs.46.0%;Z=-3.519,-2.336,-5.106,all P<0.05).Among the evaluation results of lesion detectability of different reconstruction algorithms,OSEM+TOF+PSF image showed the mediastinal lymph node metastasis most clearly(87.4%of the lesions were clearly existing),which was significantly higher than that of OSEM image(73.1%of lesions were clearly existing)(χ2=11.704,P=0.001),however,the proportion of lesions clearly existing in OSEM+PSF image did not significantly increase compared with OSEM image(73.1%vs.75.8%;χ2=0.361,P=0.548).Conclusion The combination of TOF and PSF can significantly improve the detection ability,SNR and SUV of mediastinal lymph node metastasis of lung cancer,especially in small and low contrast lesions.
NETL
NSTL
万方数据