Figure 2.

Centreline plane-based measurements. (A) Analysis workflow, multiple analysis planes were created along the centreline to measure vessel diameter and flow parameters, anatomic landmark planes are displayed for distance reference. (B) Example of manual measurement of diameter using standard CE-MRA, this measurement was performed only in 20 cases for diameter validation and the larger diameter was used for assessment. (C) Automatic measurement of diameters obtained from a plane based on the 3D CE-MRA segmentation (red line corresponds to segmented vessel area), note that a circular cross section was assumed to back calculate diameter (d). (D) Examples of flow displacement measurements for symmetric and asymmetric flow profiles. The black dashed line corresponds to the vessel centreline. The normalized flow displacement was calculated as the distance from the vessel centreline to the positive velocity-weighted centre of mass (black circle) normalized to the vessel diameter. The corresponding equation is also shown in (D). MPA, main pulmonary artery.