Quantification of regional ventilation-perfusion ratios with PET. J Nucl Med, 44(12):1982–1991. Evaluation Studies

The topographic matching of alveolar ventilation (V̇A) and per-fusion (Q̇) is the main determinant of gas exchange efficiency of the lung. However, no pulmonary functional imaging technique has been shown to predict whole-lung gas exchange in health and disease. This study aims to present a PET-based method to estimate regional alveolar ventilation-to-perfusion ratios (V̇A/Q̇) predictive of arterial blood gases. Methods: The method is based on the regional tracer kinetics of 13N-nitrogen (13NN) after an intravenous bolus injection during a breath-hold period and subsequent washout from the lungs with resumption of breath-ing. The method takes into account the presence of inter- and intraregional nonuniformities at length scales smaller than the imaging spatial resolution. An algorithm used regional tracer washout to classify regional V̇A/Q ̇ uniformity. Intraregional V̇A/Q̇ mismatch in nonuniform regions was described with a 2-com