The additional value of 18F-FDG PET/CT imaging in guiding the treatment strategy of non-tuberculous mycobacterial patients

Objectives Non-tuberculous mycobacteria (NTM) infection is an increasing health problem due to delaying an effective treatment. However, there are few data on .sup.18F-FDG PET/CT for evaluating the status of NTM patients. The aim of this study was to investigate the potential value of .sup.18F-FDG PET/CT in guiding the treatment strategy of NTM patients. Methods We retrospectively analyzed the cases of 23 NTM patients who underwent .sup.18F-FDG PET/CT. The clinical data, including immune status and severity of NTM pulmonary disease (NTM-PD), were reviewed. The metabolic parameters of .sup.18F-FDG included maximum standardized uptake value (SUV.sub.max), SUV.sub.max of the most FDG-avid lesion (SUV.sub.Top), SUV.sub.Top/SUV.sub.max of the liver (SUR.sub.Liver), SUV.sub.Top/SUV.sub.max of the blood (SUR.sub.Blood), metabolic lesion volume (MLV), and total lesion glycolysis (TLG). The optimal cut-off values of these parameters were determined using receiver operating characteristic curves. Results There were 6 patients (26.09%) with localized pulmonary diseases and 17 patients (73.91%) with disseminated diseases. The NTM lesions had high or moderate .sup.18F-FDG uptake (median SUV.sub.Top: 8.2 [+ or -] 5.7). As for immune status, the median SUV.sub.Top in immunocompromised and immunocompetent patients were 5.2 [+ or -] 2.5 and 10.0 [+ or -] 6.4, respectively, with a significant difference (P = 0.038). As for extent of lesion involvement, SUR.sub.Liver and SUR.sub.Blood in localized pulmonary and disseminated diseases were 1.9 [+ or -] 1.1 vs. 3.8 [+ or -] 1.6, and 2.7 [+ or -] 1.8 vs. 5.5 [+ or -] 2.6, respectively, with a significant difference (P = 0.016 and 0.026). Moreover, for disease severity, SUV.sub.max of the lung lesion (SUV.sub.I-lung) and SUV.sub.max of the marrow (SUV.sub.Marrow) in the severe group were 7.7 [+ or -] 4.3 and 4.4 [+ or -] 2.7, respectively, significantly higher than those in the non-severe group (4.4 [+ or -] 2.0 and 2.4 [+ or -] 0.8, respectively) (P = 0.027 and 0.036). The ROC curves showed that SUV.sub.Top, SUR.sub.Liver, SUR.sub.Blood, SUV.sub.I-lung, and SUV.sub.Marrow had a high sensitivity and specificity for the identification of immune status, lesion extent, and severity of disease in NTM patients. Conclusion .sup.18F-FDG PET/CT is a useful tool in the diagnosis, evaluation of disease activity, immune status, and extent of lesion involvement in NTM patients, and can contribute to planning the appropriate treatment for NTM