Fig. 6. Specific regional net 18F-fluorodeoxyglucose uptake rate (Kis) in supine sheep after 2 h of mechanical ventilation with positive end-expiratory pressure = 0 cm H2O and plateau pressure of 30-32 cm H2O, without (control, n = 6) and with mild endotoxemia (endotoxin, n = 6). Each lung region corresponds to one third of the lungs segmented according to the amount of perfusion (A , B ) or gas fraction (C , D ). Low, intermediate, and high in the horizontal axes correspond to the first, second, and third tertiles, respectively. Note the linear relationship between perfusion and Kisas opposed to a relationship with a minimum at intermediate values between gas fraction and Kis. *P < 0.05 middle versus ventral regions; †P < 0.05 dorsal versus ventral regions; ‡P < 0.05 dorsal versus middle regions. Circles represent individual data points.