结节病18F-FDG PET/CT的诊断及误诊原因分析

PET/CT for the diagnosis of sarcoidosis and analysis on reasons of misdiagnosis

目的 对行PET/CT检查的11例结节病患者进行回顾性分析,为结节病的正确诊断提供依据.方法 对11例经手术病理检查证实（5例）和随访证实（6例）的结节病患者进行回顾性临床资料总结,根据18F-脱氧葡萄糖（FDG）PET/CT图像特征,结合病灶累及部位、分布特点、大小、标准摄取值（SUV）特点及误诊比例等进行分析总结.结果 （1）淋巴结累及者共11例：其中纵隔及双肺门淋巴结累及者11例,锁骨上窝淋巴结累及者8例,腹膜后淋巴结累及者8例,盆腔淋巴结累及者3例.（2）结外脏器累及者共7例：包括肺内结节及片状阴影4例,肝累及2例,腮腺及颞肌累及1例,双侧髂骨和骶骨累及1例.（3）病灶大小：最大直径1.0～4.6 cm之间 病灶密度：CT平扫示病变淋巴结密度30～40 HU之间,肺内病灶呈淡薄密度影 肝内病灶呈等或稍低密度影.代谢情况：所有病灶代谢均明显增高者6例 部分病灶代谢明显增高、部分轻中度增高者2例 代谢均轻中度增高者3例.（4）PET/CT正确诊断6例 误诊5例,其中误诊为恶性淋巴瘤4例、肺癌1例.结论 18FFDG PET/CT可灵敏、准确地反映结节病的全身病灶分布范围和病灶活性,但部分病例易被误诊为恶性肿瘤,尤其是恶性淋巴瘤.根据PET/CT影像特点并结合临床能提高结节病的诊断准确性.

Objective To retrospectively review the PET/CT imaging features of sarcoidosis and improve the diagnostic accuracy of this benign disease.Methods The PET/CT imaging characteristics and clinical data, including lesion size, distribution, standardized uptake value （SUV） and the ratio of misdiagnosis, of 11 sarcoidosis patients （5 confirmed pathologically and 6 clinically） were retrospectively analyzed.Results （1） Eleven patients had lymph node involvement：mediastinum and hilar lymphadenopathy in 11/11, supraclavicular fossa lymphadenopathy in 8/11, retroperitoneal lymphadenopathy in 8/11, pelvic cavity lymphadenopathy in 3/11.（2） Extrathoracic lesions were found in 7/11 with 4 lung involvement, 2 liver involvement, 1 parotid gland and temporalis involvement and 1 bilateral iliac and sacral bone involvement.（3） The size of the lesions ranged from 1.0 to 4.6 cm and the CT density ranged from 30 to 40 HU.The lesions in the lung are hypodense and in the liver are slightly hypo-or iso-dense.18F-fluorodeoxyglucose （FDG） uptake of all lesions was definitely increased in 6 cases 18F-FDG uptake of some lesions was moderately or definitely increased in 2 cases, and slightly increased uptake in 3 cases.（4） The PET/CT diagnosis was consistent with the final diagnosis in 6/11.The 5 cases of misdiagnosis were malignant lymphoma （4/11） and lung cancer （ 1/11 ）.Conclusions Differentiation between sarcoidosis and lymphoma in patients presenting with hilar lynphadenopathy can be difficult.Whole-body PET/CT may be helpful in the differentiation of the two diseases.