Fig. 5
3D renderings and animations of perfusion distributions. A Representative 3D renderings of the mean-normalized distribution of perfusion for PAH and healthy control subjects at baseline and after O2 + iNO (animated in Videos V1 (https://doi.org/10.6084/m9.figshare.12442589) and V2 (https://doi.org/10.6084/m9.figshare.12442784)) showing the effects of the administration of O2 + iNO based on PET-CT imaging in supine position. The patchy areas of high perfusion illustrate the size and location of regional variations behind the representations in perfusion-height maps (Fig. 2). B 3D renderings of the regional changes in perfusion corresponding to the perfusion distributions in panel A (animated in Videos V3 (https://doi.org/10.6084/m9.figshare.12442787) and V4 (https://doi.org/10.6084/m9.figshare.12442790)). The web-like structure of perfusion increases (yellow) and decreases (blue) instead of gradual changes in perfusion among different regions illustrates the spatial variations behind the difference maps of the perfusion-height distribution (Fig. 3). The relatively small sizes suggest the involvement of smaller anatomical structures together with larger anatomical structures linked to the average changes in larger regions. In all 3D renderings, the orientation of the lungs is shown by a small mannequin. Color scales are fully transparent either for average perfusion (A, V1, and V2) or zero change (B, V3, and V4), opaqueness increases with the deviation from these values, and differences in color between PAH and controls are differences in magnitude. Rotating 3D renderings with periodic switching between air and O2 + iNO show the location and changes in high and low perfusion areas. This provides a spatial perception of their location and their magnitude lacking in the still images – video download provides the highest resolution and allows playback in loop mode