Figure 3:

Semiquantitative scoring of black blood slow flow score. The score is based on how proximal signal can be seen in pulmonary arteries, where 0 = no slow flow, 1 = signal within segmental pulmonary arteries, 2 = signal within lobar branches, 3 = signal within distal main pulmonary artery, 4 = signal within proximal main pulmonary artery, and 5 = signal within proximal main pulmonary artery. Diagram demonstrates different parts of pulmonary artery and naming convention. Example images of each score are provided with their mean pulmonary artery pressure (mPAP) as a reference.