1Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, United States; 2Department of Biomedical Engineering, Duke University, Durham, NC, United States; 3Department of Medicine, Duke University Medical Center, Durham, NC, United States; 4GE Healthcare, Amersham, United Kingdom; 5Department of Radiology, Duke University Medical Center, Durham, NC, United States
We investigate the signal intensity distribution in dissolved 129Xe images from healthy subjects and subjects with chronic obstructive pulmonary disease (COPD). In addition to gravity-dependent SNR gradients, images from healthy subjects display significant isogravitational heterogeneity as measured by the coefficient of variation (CV). Differences in SNR and CV are observed between the left and right lungs. Left-right differences are absent in ventilation images, suggesting tissue compression by the heart alters the signal distribution in the left lung. Gravitational and left-right differences are reduced or absent in subjects with COPD, indicating dissolved 129Xe is sensitive to disease-associated changes in lung physiology.