Fig. 5
From: The effect of posture on airflow distribution, airway geometry and air velocity in healthy subjects
Regional ventilation maps for a healthy subject in supine (A) and right lateral position (B), as well as the relative effect between both. substantial relative ventilation defect can be seen in the left lung as a result of the right lateral position, with regional effect values up to 25. Ventilation maps are CT based representations of regional ventilation, derived from pulmonary CT images acquired at two different inflation levels, functional residual capacity (FRC) and total lung capacity (TLC) without the use of exogenous contrast, by assuming that regional changes in lung volume relate to regional ventilation The Jacobian determinant of the deformation field from FRC to TLC is calculated, which measures the differential expansion of the image