结节病^(18)F-氟代脱氧葡萄糖PET/CT的影像诊断及误诊分析

^(18)F-fluorodexoxyglucose PET/CT Imaging Diagnosis and Misdiagnosis Analysis of Sarcoidosis

目的分析总结结节病18F-氟代脱氧葡萄糖(18F-fluorodeoxyglucose,18F-FDG)正电子发射断层显像/计算机体层摄影(positron emission tomography/computed tomography,PET/CT)的图像特征,为提高该病正确诊断率以及减少误诊提供一定的参考依据。方法收集整理23例结节病患者的影像资料,归纳总结结节病的18F-FDG PET/CT图像特征,并对误诊病例进行讨论分析。结果(1)累及淋巴结:所有病例都伴有纵隔与肺门淋巴结受累并且表现为双侧对称分布,锁骨上窝、颈部、腋窝以及腹股沟淋巴结也多为双侧受累并对称分布,而腹部和盆腔淋巴结以肝门区及腹膜后累及居多。所有受累淋巴结的放射性摄取呈不同程度增高,最大径均不低于1.0 cm。(2)累及结外脏器:18例肺部累及者主要表现为肺内散在的结节影及斑片状实变影,放射性摄取多数呈不同程度增高,最大标准化摄取值(standard uptake values,SUVmax)值0.9~5.5;5例胸膜累及者主要呈局部增厚或小结节样改变;3例肝脾累及者中1例表现为肝脾内稍低密度影伴放射性摄取增高,另外2例脾脏的放射性分布呈弥漫性增高;3例骨骼累及者局部可见18F-FDG浓聚灶,相应部位并无骨质破坏;3例皮肤及皮下累及者可见全身皮疹或皮下小结节;2例心包累及者以心包肥厚为主要表现。(3)5例误诊,主要被误诊为淋巴瘤及肺部肿瘤。结论纵隔及双肺门淋巴结对称性肿大伴18F-FDG高摄取是结节病PET/CT显像的典型表现,部分病例容易被误诊为淋巴瘤及肺部肿瘤,加深对该病PET/CT影像表现及鉴别要点的认识有助于提高诊断准确率。

Objective To summarize and analyze the 18F-fluorodeoxyglucose(18F-FDG)positron emission tomography/computed tomography(PET/CT)image features of sarcoidosis,and to provide reference basis for improving the correct diagnostic rate and reducing misdiagnosis of sarcoidosis.Methods The 18F-FDG PET/CT image data of 23 patients with sarcoidosis were collected and summarized,then the misdiagnosed cases were discussed and analyzed.Results(1)Lymph nodes involvement:all cases were accompanied by mediastinal and bilateral hilar lymph nodes involvement and showed a symmetrical distribution.The lymph nodes involvement in neck,supraclavicular fossa,axilla and groin area also showed a symmetrical distribution.Abdominal and pelvic lymphadenopathy were mostly distributed in the porta hepatis and retroperitoneum.All the lymphadenopathy showed radioactivity increase in varying degrees,and the maximum diameter were not less than 1.0 cm.(2)Extranodal organ were involved:eighteen cases of pulmonary involvement mainly manifested as scattered nodules and patchy shadows,and most of the radioactivity uptake was increased in varying degrees,standard uptake values(SUVmax)ranged from 0.9 to 5.5.Five pleural involvement mainly showed small nodules or thickening changes;one case of the 3 liver or spleen involvement showed slightly low-density shadows in the liver and spleen and with increased radioactivity uptake,the other two cases showed a diffuse increase in radioactivity in the spleen;three bone involvement showed high 18F-FDG uptake foci,and there was no bone destruction in the corresponding part;three skin involvement mainly showed whole body rash or subcutaneous nodules;two pericardium involvement mainly showed pericardial thickening.(3)Five cases were misdiagnosed,mainly as lymphoma and lung tumor.Conclusion Symmetrical enlargement of mediastinal and bilateral hilar lymph nodes with high 18F-FDG uptake is a typical manifestation of PET/CT imaging of sarcoidosis.As some cases of sarcoidosis are prone to be misinterpreted as lymphoma and lung tumor,deepening the knowledge of the PET/CT imaging features and distinguishing signs of sarcoidosis can be used to improve the diagnostic accuracy of the disease.