What is the utility of FDG PET in nonneoplastic thoracic disorders?
FDG PET is useful to assess the spatial extent and inflammatory activity of disease, to aid in the identification of sites suitable for tissue sampling, and to monitor the effects of therapy in patients with nonneoplastic thoracic disorders such as sarcoidosis, interstitial lung disease (ILD), pneumoconiosis, acute lung injury (ALI)/adult respiratory distress syndrome (ARDS), chronic obstructive pulmonary disease (COPD), and cystic fibrosis. In addition, extrapulmonary sites of altered metabolism in the body associated with these conditions can be detected as well. For example, increased FDG uptake may be seen in involved thoracic and extrathoracic lymph nodes in patients with sarcoidosis. Increased FDG uptake is sometimes seen in the right ventricular myocardium in patients who have secondary pulmonary hypertension. Increased FDG uptake may be seen in the thoracic and abdominal muscles of patients with COPD, given the presence of expiratory pulmonary air trapping occurring from loss of pulmonary elastic recoil and increased small airways resistance.