基于大津法的自衰减校正PET图像重建技术在18F-AV45显像中的应用

目的探索基于大津法的自衰减校正PET(sacPET)重建技术在¹⁸F-florbetapir(AV45)显像中的应用。方法2018年11月到2019年12月间在中山大学附属第一医院前瞻性招募7例确诊的阿尔茨海默病(AD)患者[男4例,女3例,年龄(69.6±4.5)岁]和3名健康对照者(HC)[男1名,女2名,年龄(68.0±4.6)岁]行¹⁸F-AV45 PET显像,利用PET采集的原始数据进行sacPET重建。通过视觉分析和半定量分析技术将sacPET数据与标准PET数据进行对比。采用Fisher确切概率法、Kappa检验和Pearson相关分析数据。结果HC组和AD组中,sacPET图像和标准PET图像的放射性分布大致相似,HC者sacPET图像的灰质、白质对比度弱于标准PET图像,而AD患者的sacPET图像上皮质高摄取区域范围小于标准PET图像。视觉分析显示在所有的受试者中,sacPET图像示阳性区域19个,标准PET示阳性区域22个,各脑区的阳性率在2种PET图像间差异无统计学意义(均P>0.05),各个脑区显像结果的总体一致性为88.00%[44/50;Kappa=0.75(95%CI:0.57~0.94),P<0.05]。半定量分析显示,sacPET图像所得到的额叶与扣带回标准摄取值比值(SUVR)低于标准PET图像(0.93±0.06与0.96±0.06和0.99±0.04与1.01±0.04;t值:5.30和5.10,均P<0.01),而顶叶、颞叶和枕叶所得SUVR值高于标准PET图像(0.78±0.08与0.68±0.07、0.97±0.07与0.91±0.08和0.94±0.11与0.71±0.12;t值:6.27、7.36和16.90,均P<0.01);2种PET图像大脑皮质SUVR相关性有统计学意义(r=0.75,P<0.001)。结论在¹⁸F-AV45显像中,sacPET重建技术无需CT扫描即可得到可靠有效的PET数据,但其准确性和精度仍有待提高。

Application of OTSU-based self-attenuation correction PET reconstruction technology in 18F-AV45 imaging

Objective To explore the application of OTSU-based self-attenuation correction PET(sacPET)reconstruction technology in ¹⁸F-florbetapir(AV45)imaging.Methods From November 2018 to December 2019,7 confirmed Alzheimer′s disease(AD)patients(4 males,3 females,age(69.6±4.5)years)and 3 healthy controls(HC;1 male,2 females,age(68.0±4.6)years)were recruited prospectively for ¹⁸F-AV45 PET imaging in the First Affiliated Hospital of Sun Yat-Sen University.Original data collected by PET acquisition was processed with sacPET reconstruction and then compared with standard PET images by visual analysis and semi-quantitative analysis.Fisher exact test,Kappa test and Pearson correlation analysis were used to analyze data.Results In HC group and AD group,the radioactive distribution showed by sacPET images and that by standard PET images were similar,and the contrast of gray-white matter in sacPET images was weaker than that in standard PET images.Moreover,the positive uptake area of the cortex in the AD group was smaller than that in standard PET images.Visual analysis showed 19 positive regions in sacPET images and 22 in standard PET images,with no statistical difference of positive rates of the sub-regions in the cortex between the two PET images(all P>0.05),and the overall consistency of 88.00%(44/50;Kappa=0.75(95%CI:0.57-0.94),P<0.05).Semi-quantitative analysis showed that the standardized uptake value ratio(SUVR)of frontal lobe and cingulate gyrus measured by sacPET was lower than that measured by standard PET(0.93±0.06 vs 0.96±0.06 and 0.99±0.04 vs 1.01±0.04;t values:5.30 and 5.10,both P<0.01),while SUVR of parietal lobe,temporal lobe and occipital lobe measured by sacPET was higher than that measured by standard PET(0.78±0.08 vs 0.68±0.07,0.97±0.07 vs 0.91±0.08 and 0.94±0.11 vs 0.71±0.12;t values:6.27,7.36 and 16.90,all P<0.01).The overall SUVR of sacPET images was significantly correlated with the standard PET images(r=0.75,P<0.001).Conclusion For ¹⁸F-AV45 imaging,sacPET reconstruction technology can obtain reliable and effective PET images without CT data,but its accuracy and precision still need to be improved.