Demonstration of excessive metabolic activity of thoracic and abdominal muscles on FDG-PET in patients with chronic obstructive pulmonary disease

Purpose: The purpose of this study was to determine if an FDG-PET study was able to visualize muscle uptake of the chest and abdomen in patients with chronic obstructive pulmonary disease (COPD). Methods: This study included 25 patients with COPD and 25 patients without COPD who had undergone a FDG-PET study. The nonattenuation-corrected images were used to determine the degree of FDG uptake in the intercostals, subscapular, abdominal rectus, and abdominal oblique muscles. The intensity of uptake in the muscles was rated on a 4-point grading scale with I being less, 2 the same, 3 slightly more, and 4 markedly more intense than the sternum. Results: Thirteen patients with COPD demonstrated FDG activity in the intercostal muscles that was equal to or greater than the sternum and the tracer was demonstrated predominantly in the inferolateral chest wall (n = 8), the entire lateral chest wall (n = 2), the posteroinferior chest wall (n = 2), and the entire chest wall (n = 1). In all 13 patients with COPD who demonstrated FDG activity in the abdominal oblique muscles, the site of muscle activity was predominantly in the anteroinferior abdominal wall (n = 8), the lateral wall (n = 4), and the anterior wall (n = 1). In patients without known COPD, the frequency and intensity of uptake in the muscles were less than those with the disease. Conclusion: This study demonstrates the ability of FDG-PET imaging to assess muscle function in respiratory disorders and may prove to be of some value in further characterizing this disorder.