Parameters computed based on K-edge subtraction images (mean ± SD). = mean specific ventilation, averaged over the three imaged lung slices; CV = coefficient of variation; VAA = ventilated alveolar area; total lung area = cumulated lung area within the three image slices; PEEP = positive end-expiratory pressure. * P < 0.005 PEEP 3 versus PEEP 9 within a condition; # P < 0.05 control versus lavage within a PEEP; § P < 0.05 lavage at PEEP 3.