Fig. 2.

Diameter and length measurements from the 3-dimensional pulmonary artery (PA) model were extracted along centerlines of vessels. Multiple diameters were taken along the centerline from a maximally inscribed radius, and lengths were measured along the centerline from subsequent bifurcation points. θ₁ and θ₂ represent the in-plane bifurcation angles of the 2 daughter vessels branching from the parent vessel. Vessel order of the segments in the model was defined with an initial Strahler ordering method, followed by a diameter-defined Strahler order and outlier resorting.