Pulmonary vascular permeability in interstitial lung disease. A positron emission tomographic study.

We evaluated pulmonary vascular permeability with positron emission tomography (PET) in 16 patients with interstitial lung disease (ILD) by measuring the pulmonary transcapillary escape rate (PTCER) for transferrin labeled with gallium-68. In patients with active ILD, defined by lung biopsy or clinical criteria, mean PTCER was significantly greater than in normal subjects (118 +/- 46 versus 21 +/- 11 x 10(-4) min-1, respectively, p less than 0.05). Mean PTCER in patients with inactive ILD, in contrast, was not different from that in normal subjects (32 +/- 10 x 10(-4) min-1, p = NS). Thus, these data suggest that PET measurements of PTCER might serve as an index of disease activity in patients with ILD.