Use of 18F-FDG PET/CT for Imaging TB Patients and Related Conditions (HIV/AIDS, Tuberculosis): Focus on Drug Resistant Extrapulmonary Tuberculosis

Over 95% of TB deaths occur in low- and middle-income Member States, where TB is among the top three causes of death for women in reproductive age. This disease has become or is becoming a medical emergency not only in developing Member States but also in some high-income countries, because of migration of people from low-income to higher-income areas, because of frequent co-infection with HIV/AIDS, and because of the development of drug-resistant strains of TB (3). Aim of this study is to engage Member States in a coordinated research project to develop a comprehensive TB imaging strategy through the use 18F-FDG PET/CT for imaging TB patients with special focus on: (a) extrapulmonary TB (b) multi drug resistant TB (MDR-TB) and (c) monitor response to therapy (Baseline 18F-FDG PET scan and repeat scan at 2 months and 6months post therapy) in order to reduce rates and deaths from TB especially drug resistant TB. Radionuclide imaging of infection has for long time relied almost exclusively on single-photon-emitting agents, evolving from early applications of 67Ga-citrate scintigraphy to scintigraphy with autologous leukocytes, labelled either directly (by in vitro incubation with agents such as 111In-Oxine or 99mTc-HMPAO before reinfusion) or indirectly (e.g., administering radiolabeled antibodies binding to surface antigens expressed by granulocytes)(1-2). The latest entry for radionuclide imaging of infection in the clinical setting is represented by PET with 18F-FDG, based on nonspecific enhanced glucose consumption of inflammatory cells and/or growing bacteria at the site(s) of infection(1-2). Nearly 11% of all deaths from infectious diseases are caused by tuberculosis (TB). This will contribute to the overall improvement of health care by accurate and early diagnosis of intractable TB infections in high risk patients through a multicentre imaging trial using 18F-FDG by increasing the detection rate of respiratory, abdominal, CNS, and postoperative infections ?related to TB. Overall, infectious disease constitutes a big burden to healthcare systems not only because of the direct costs related to treatments, but also in terms of parameters describing the overall economic and social burden deriving from associated disabilities and chronic debilitating illnesses, such as the disability-adjusted life years and the health-adjusted life expectancy. The top infectious diseases causing deaths worldwide are lower respiratory infections (including pneumonia and influenza), chronic obstructive pulmonary disease, diarrheal diseases, HIV/AIDS, and tuberculosis (TB). While the impact of radionuclide imaging in the first four such infectious conditions is rather limited, special attention should be paid to the potential role of nuclear medicine imaging in certain stages of TB infection. Such role is not to be seen in the diagnostic approach to TB, but rather in subsequent stages, for characterization of the disease and for assessing its response to therapy.