肺单发结核瘤^(18)F-FDG PET/CT误诊分析

Misdiagnosis of ^(18)F-FDG PET/CT in Single Pulmonary Tuberculoma

目的肺结核瘤是造成^(18)F-脱氧葡萄糖(FDG)PET/CT假阳性的常见原因。本研究拟分析13例肺单发结核瘤(SPT)的^(18)F-FDG PET/CT影像学表现,以提高认识,减少误诊率。资料与方法回顾性分析经手术病理证实的13例SPT的^(18)F-FDG PET/CT表现,统计不同预设标准诊断SPT的准确性。结果 13例SPT早期SUVmax平均值为4.3±2.8,其中10例行延迟显像,延迟SUVmax平均值为4.3±2.6,滞留指数(RI)平均值为(14±23)%,7例均显示延迟SUVmax进一步上升。无纵隔淋巴结摄取、双侧对称和病变同侧的纵隔淋巴结摄取分别为6例、3例和4例。CT示6例无分叶,5例浅分叶,中分叶及深分叶各1例;9例无毛刺,3例长毛刺,1例短毛刺;4例有卫星灶,9例无卫星灶;4例有钙化,9例无钙化。预设SPT的PDG摄取低于纵隔血池、早期显像SUVmax<2.5、RI<10%、良性钙化或卫星灶为良性诊断标准,诊断准确性分别为8%、23%、40%和62%。结论 ^(18)F-FDG PET对SPT的诊断价值有限,不及CT的诊断效能,此时需仔细观察CT形态学特征。

Purpose Pulmonary tuberculoma is one of the most well-known diseases that may cause false positive diagnosis in （18）F-FDG PET/CT scan. The analysis of （18）F-FDG PET/CT manifestations of 13 cases of single pulmonary tuberculoma（SPT） aims to better distinguish tuberculoma from lung cancer. Materials and Methods We retrospectively evaluated the PET/CT findings of 13 patients with SPT who underwent ^（18）F-FDG-PET/CT scan and later were confirmed by surgery and pathology. Different interpretation criteria were established as individual predictors of benignity. Results The mean maximum standardized uptake value（SUVmax） of 13 SPTs was 4.3±2.8 and 4.3±2.6 on early and delayed phases, respectively. The mean retention index（RI） was（14±23）%. Seven of 10 SPTs showed increased FDG uptake on delayed phase. Six SPTs showed absent uptake in mediastinal lymph node, 3 SPTs showed symmetrical bilateral uptake in mediastinal lymph node and four displayed unilateral uptake in mediastinal lymph node. The CT scan presented absent or shallow lobulation in 11 SPTs, absent spiculation or long spiculation in 12 SPTs, satellite nodules in 4 SPTs and nodular calcification in 4 SPTs. When SPT FDG uptake was lower than mediastinum and the indexes such as early SUVmax2.5, RI10% and presence of benign calcification or satellite nodules were set as interpretation criteria for predicting benignity, the accuracy rate reached 8%, 23%, 40% and 62%, respectively. Conclusion ^（18）F-FDG PET has limited diagnostic value in SPT and is inferior to CT. More attention should be paid to CT characteristics.