肺隐球菌病18F-FDG PET/CT显像特征分析

目的探讨肺隐球菌病（PC）的18F-FDG PET/CT影像学表现及PET代谢特征。方法回顾性分析2011年3月至2015年10月行18F-FDG PET/CT检查，经病原学或病理检查确诊为PC的22例患者的临床资料，分析其CT类型（单发结节型、多发结节型、肺炎型、混合型）及征象、PET代谢特征（低代谢型、高代谢型）。结果22例PC患者中，单发结节型9例，多发结节型7例，肺炎型1例，混合型5例。发病部位以下肺为主，累及一侧或双侧肺下叶15例（15/22，68.18%），其中仅累及右肺下叶9例（9/22，40.91%）、仅累及左肺下叶2例（2/22，9.09%）。22例PC患者中，有实性结节病灶21例，病灶CT征象以血管集束征（12/21）、毛刺征（10/21）、晕征（8/21）最常见，支气管充气征（6/21）及分叶征（4/21）次之。病变结节18F-FDG PET最大标准化摄取值为1.00~12.67，以高代谢型为主（20/22），6例单发结节误诊为恶性肿瘤。结论PC以单发或多发结节为主，葡萄糖代谢标准化摄取值差异大，误诊率较高。肺内葡萄糖高代谢的单发结节在诊断为肺癌时需与PC相鉴别。

The characteristics of 18F-FDG PET/CT in pulmonary cryptococcosis

ObjectiveTo investigate the 18F-FDG PET/CT imaging characteristics and PET metabolic characteristics of pulmonary cryptococcosis (PC).MethodsA retrospective study was performed in 22 patients with PC (16 male and 6 female; 34-81 years old), confirmed through etiology or pathological examination from March 2011 to October 2015. To analyze the clinical data, CT patterns (single nodule, multiple nodules, pneumonia type, and mixed type), CT signs (vessel convergence sign, spiculation sign, halo sign, air bronchogram, and lobulation), and FDG metabolic patterns(hypermetabolism and hypometabolism) of PC were analyzed.ResultsPC was characterized by single nodule(9/22), multiple nodules(7/22), pneumonia type (1/22), and mixed type (5/22) for the 22 patients with PC. Most of the nodules were found in the inferior lobe of the lung. There were 15 cases(15/22, 68.18%) involving one or both inferior lobe of the lungs, of which 9 cases(9/22, 40.91%) involving the right inferior lobe, 2 cases(2/22, 9.09%) involving the left inferior lobe. Vessel convergence sign(12/21) was the most common sign, followed by spiculation(10/21), halo sign(8/22), air-bronchogram sign(6/21), and lobulation(4/21) with nodules on CT scan. The maximum standardized uptake value of PC was from 1.00 to 12.67 on 18F-FDG PET/CT scan, and hypermetabolism type (20/22) was the predominant pattern. Six patients with single nodule were misdiagnosed as malignant tumors.ConclusionsMost cases of PC were characterized with single and multiple nodules. A relative high rate of misdiagnosis was obtained using 18F-FDG PET/CT scan with varied standardized uptake value. Diagnosis of single nodule with high FDG metabolism in lung cancer should differentiate from PC.