不同阈值勾画^(18)F-FDG PET/CT心脏肿瘤ROI鉴别其良恶性

Different thresholds in tracing ROI of heart neoplasms on^(18)F-FDG PET/CT images for differentiating benign and malignant tumors

目的评价采用不同阈值勾画^(18)F-FDG PET/CT图像中病灶ROI鉴别心脏良恶性肿瘤的价值。方法纳入64例心脏肿瘤患者(65个病灶),根据病理学或长期随访结果分为良性组(n=27)和恶性组(n=38)。采用3种阈值(Th 2.5、Th 40%和Th bgd)勾画心脏肿物,测量并比较病灶^(18)F-FDG PET/CT代谢和形态学参数,包括最大标准摄取值(SUV max)、平均标准摄取值(SUV mean)、代谢肿瘤体积(MTV)、病灶糖酵解总量(TLG)、最大CT(CT max)值、平均CT(CT mean)值及CT值中位数(CT median)。以多因素Logistic回归分析良、恶性组差异具有统计学意义的参数,绘制受试者工作特征(ROC)曲线,计算曲线下面积(AUC),评价3种阈值诊断心脏良恶性肿瘤的效能。结果采用3种阈值勾画ROI得到的肿瘤SUV max一致,其鉴别诊断心脏良恶性肿瘤的AUC均为0.92;良、恶性肿瘤之间SUV mean、MTV及TLG差异均具有统计学意义(P均<0.05)。根据SUV mean诊断良、恶性肿瘤时,以阈值Th 40%的诊断效能最佳;以MTV及TLG诊断时,阈值Th 2.5均具最佳效能。多因素Logistic回归结果显示Th 40%与Th bgd诊断效能均较好,且Th bgd的敏感度及准确率均高于Th 40%。结论根据PET代谢参数可鉴别心脏良恶性肿瘤。SUV max截断值为6.75时,鉴别心脏良恶性肿瘤具有较好效能;采用多参数评价时,3种阈值中,以Th bgd效能最优。

Objective To observe the value of different thresholds in tracing ROI of heart neoplasms on 18 F-FDG PET/CT images for differentiating benign and malignant cardiac tumors.Methods A total of 64 patients with 65 primary cardiac masses cases were enrolled.The tumors were divided into benign group(n=27)and malignant group(n=38)based on pathology or long-term follow-up outcomes.Three thresholds,i.e.Th 2.5,Th 40%,and Th bgd were used to trace ROIs of tumors,and 18 F-FDG PET/CT metabolic and morphological parameters,including the maximum standard uptake value(SUV max),the mean standard uptake value(SUV mean),metabolic tumor volume(MTV),the total lesion glycolysis(TLG),maximum CT(CT max)value,mean CT(CT mean)value and median CT(CT median)value were measured and compared between groups and among 3 thresholds.Multivariate Logistic regression analysis was performed of parameters being statistically different between benign and malignant tumors.The receiver operating characteristic(ROC)curves were drawn to calculate the area under the curve(AUC)and judge the efficacy of 3 thresholds for differentiating benign and malignant cardiac tumors.Results SUV max of ROIs traced with 3 thresholds were consistent,and AUCs for diagnosing benign and malignant heart masses were all 0.92.SUV mean,MTV and TLG measured with 3 methods were all statistical different between 2 groups(all P<0.05).When SUV mean was used to diagnose benign and malignant tumors,Th 40%had the best diagnostic performance;when MTV and TLG were used,Th 2.5 had the best performance.Multivariate Logistic regression showed that the diagnostic efficiency of Th 40%and Th bgd method were both good,while the sensitivity and accuracy of Th bgd were higher than those of Th 40%.Conclusion PET metabolic parameters were important for differentiation of benign and malignant masses of the heart.Taken SUV max 6.75 as the threshold had good diagnostic efficiency.Th bgd was the best for multi-parameter evaluation of benign and malignant cardiac tumors,which had good diagnostic performances.