Dual-time point whole-body 18F-fluorodeoxyglucose PET/CT imaging in undiagnosed mediastinal lymphadenopathy: a prospective study of 117 patients with sarcoidosis and TB.

Sarcoidosis and TB, the two most common benign causes of mediastinal lymphadenopathy, share remarkable clinical, radiologic, and histologic similarities. 1 Diff erentiation between the two remains a diffi cult task for pulmonary physicians, particularly in countries with a high burden of TB. 2 We performed a dual-time point 18 F-fl uorodeoxyglucose (FDG) PET/CT scan in 117 consecutive patients with undiagnosed mediastinal lymphadenopathy ( Table 1 ). Th e study was approved by the Ethics Review Committee (No. 1TRG/PG2012/20234-58) of our institution, and written informed consent was obtained from all subjects. A fi nal diagnosis of TB (n 5 29) or sarcoidosis (n 5 88) was made at 6 months follow-up based on clinical response to the treatment ( Fig 1 ).