Usefulness of FDG PET/CT in the management of tuberculosis

Abstract

Background: The aim of our study is to describe the FDG-PET/CT findings in patients with tuberculosis and to correlate them with the patient's prognosis.

Methods: We retrospectively collected data from patients with tuberculosis, who had an FDG-PET/CT performed prior to treatment initiation from 2010 to 2015.

Results: Forty-seven out of 504 patients with active tuberculosis diagnosis (9.33%) underwent an FDG-PET/CT. The reasons for performing the FDG-PET/CT were: characterization of a pulmonary nodule (24; 51.1%), study of fever of unknown origin (12; 25.5%), study of lymph node enlargement (5; 10.6%) and others (6; 12.8%). Median age was 64 (IQR 50-74) years and 31 (66%) patients were male. Twenty-six (55.3%) patients had an immunosuppressant condition. According to the FDG-PET/CT, 48.6% of the patients had more than 1 organ affected and 46.8% had lymph node involvement. Median SUVmax of the main lesion was 5 (IQR 0.28-11.85). We found an association between the FDG accumulation and the size of the main lesion with a correlation coefficient of 0.54 (p<0.002). Patients with an unsuccessful outcome had a higher ratio SUVmax main lesion / SUVmean liver (1.92 vs 7.67, p<0.02).

Conclusions: In our cohort, almost half of the patients had more than 1 organ affected and 46.8% of them had lymph node involvement. FDG uptake was associated with the size of the main lesion and seems to be related to the treatment outcome. The extent of its potential to be used as an early predictor of treatment success still needs to be defined.

Fig 1. Scatter diagram paring higher diameter of the main lesion (mm) and SUV of the main lesion.

Fig 2. A 20-year-old woman with a mediastinal mass with a necrotizing granulomatosis in the histologic study and a positive culture for M. tuberculosis.

Vertebral lesions were also observed at C5,C6, D5, D6, D7, D11 and L2. A and B (axial plane), E and F (coronal plane), H and I (sagittal plane)) Initial 18F-FDG PET/CT demonstrated an increase uptake in the mediastinic mass with lymph node basin involvement. C and D (axial plane) G and H (coronal), J and K (sagittal plane)) Follow-up 18F-FDG PET/CT after two month of treatment showed reduced 18F-FDG uptake. Concomintant CT showed reduction in the mediastinal mass size and lymph node involvement.