The use of positron emission tomography/CT in the diagnosis of tuberculosis-associated uveitis.

BACKGROUND: Detection of tuberculosis as the underlying disease in uveitis can be problematic because of the limited sensitivity of conventional diagnostic methods, especially in the case of latent infection. The aim of our study was to evaluate the clinical usefulness of (18)F-fluorodeoxyglucose positron emission tomography/CT ((18)F-FDG-PET/CT) in patients with uveitis and positive interferon-γ release assay.
METHODS: We screened 95 patients with different uveitis forms by QuantiFERON TB-Gold test. Positive results were found in 24 cases. (18)F-FDG-PET/CT was performed in 20 QuantiFERON-positive patients. PET/CT images were evaluated for the presence, size and metabolic activity of hilar and mediastinal lymph nodes and pulmonary lesions.
RESULTS: In nine patients (45%) PET/CT detected increased FDG uptake in mediastinal or hilar lymph nodes. In two patients Mycobacterium tuberculosis was detected in culture after PET/CT-guided lymph node biopsy. In seven patients (35%) with serpiginous choroiditis partly calcified lymph nodes without FDG-uptake were found. Remission of uveitis was achieved in nine of 11 (82%) anti-tuberculosis-treated patients with progressive course of uveitis.
CONCLUSION: In QuantiFERON-positive patients with severe uveitis forms, such as serpiginous choroiditis and occlusive retinal vasculitis, (18)F-FDG-PET/CT is useful to identify lesions appropriate for biopsy and helps to establish the diagnosis and appropriate therapy for presumed tuberculosis-induced intraocular inflammation.