Measurements of pulmonary vascular permeability with PET and gallium-68 transferrin.
We quantified pulmonary vascular permeability with positron emission tomography (PET) and gallium-68-(68Ga) labeled transferrin. Six dogs with oleic acid-induced lung injury confined to the left lower lobe, two normal human volunteers, and two patients with the adult respiratory distress syndrome (ARDS) were evaluated. Lung tissue-activity measurements were obtained from sequential 1-5 min PET scans collected over 60 min, after in vivo labeling of transferrin through intravenous administration of [68Ga]citrate. Blood-activity measurements were measured from simultaneously obtained peripheral blood samples. A forward rate constant describing the movement of transferrin from pulmonary vascular to extravascular compartments, the pulmonary transcapillary escape rate (PTCER), was then calculated from these data using a two-compartment model. In dogs, PTCER was 49 +/- 18 in normal lung tissue and 485 +/- 114 10(-4) min-1 in injured lung. A repeat study in these dogs 4 hr later showed no significant change. Values in the human subjects showed similarly marked differences between normal and abnormal lung tissue. We conclude that PET will be a useful method of evaluating vascular permeability changes after acute lung injury.
D000818:Animals; D002199:Capillary Permeability; D004285:Dogs; D005710:Gallium Radioisotopes; D006801:Humans; D008168:Lung / Q000098:blood supply*; D009829:Oleic Acids; D011654:Pulmonary Edema / Q000139:chemically induced / Q000000981:diagnostic imaging; D012128:Respiratory Distress Syndrome / Q000000981:diagnostic imaging; D014055:Tomography, Emission-Computed; D014168:Transferrin
D005710:Gallium Radioisotopes; D009829:Oleic Acids; D014168:Transferrin