PET/CT for the diagnosis of sarcoidosis and analysis on reasons of misdiagnosis / 中华核医学杂志

ABSTRACT

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 involvementmediastinum 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.