A quantitative correlation of extravascular lung water accumulation with vascular permeability and hydrostatic pressure measurements: a positron emission tomography study

Abstract

In 11 supine dogs, we related regional lung water concentration (rLWC) measurements made with positron emission tomography (PET) after canine oleic acid (OA)-induced acute lung injury to extravascular lung water measurements by the thermal-green dye indicator dilution technique (EVLW-TGD), and to measurements of vascular permeability (also by PET) and hydrostatic pressure. The rLWC measurements correlated well with EVLW-TGD (R 2 = 97%). Changes in LWC did not correlate with either the pulmonary wedge pressure or PET measurements of protein leak (as an index of vascular permeability), but were related when both variables were considered together (R 2 = 73%). Lung water concentration increased significantly 60 minutes after OA, primarily in dorsal, gravity-dependent lung regions, with a small, but statistically significant, change over the next 75 minutes. These data suggest that PET measurements of LWC or EVLW on one tomography slice can be representative of changes in EVLW in the lung as a whole after diffuse lung injury. Furthermore, the magnitude of edema accumulation after acute lung injury can be accurately predicted by quantitative measurements of hydrostatic pressure and of protein leak using PET.