FDG PET keeps tabs on lung oxygenation by quantifying pulmonary blood flow

In cases of acute lung injury, pulmonary blood flow (PBF) provides potentially critical information about lung aeration. An FDG PET method of compartmental modeling may quantify PBF by estimating regional fraction of blood, a breath of fresh air for pulmonary imaging, according to a study published August 1 in the Journal of Nuclear Medicine.

Céline Pouzot, PhD, from the Clinic for Small Animal Emergency and Intensive Care Unit, VetAgro Sup, Campus Vétérinaire de Lyon in Marcy l’Etoile, France, and colleagues conducted a randomized and controlled preclinical study inducing acute lung injury in pigs followed by compartmental modeling of pulmonary FDG PET to see if fraction of blood was an effective method of evaluating PBF. Results showed high concurrence between PBF and blood fraction, potentially adding functionality to FDG PET studies of pulmonary inflammation.

“PET/CT has the potential to be used to study ventilation, perfusion, and lung inflammation with a single tracer,” wrote Pouzot et al.

For this study, researchers split pig models into three groups: those administered acute lung injury by hydrochloric acid inhalation at different levels of positive end-expiratory pressures in both prone and supine positions, those injured by ventilator and an uninjured control group. All underwent F-18 FDG PET to assess inflammation and to estimate PBF by compartmental modeling of 10 areas of the anterior-to-posterior dimension of the lung and calculating regional blood flow. Results indicated a very strong correlation between fraction of blood and PBF (0.9).

“The main findings of the present study were that assessment of [regional blood fraction] by compartmental modeling of F-18 FDG kinetics provides an unbiased and precise estimation of PBF and that this method is reliable in both normal animals and animals with lung injury and over wide ranges of [tidal volumes and positive end-expiratory pressures],” wrote Pouzot et al. “Taken together, these findings encourage the use of this technique to assess PBF when F-18 FDG PET is performed.”