Table 1.

Radiographic metrics

Hypothesized predictors of PH	How measured
Main pulmonary artery diameter (PA)	Widest lumen at or near level of PA bifurcation *
Right pulmonary artery diameter (RPA)	Widest lumen caudal to ascending aorta
Left pulmonary artery diameter (LPA)	Widest lumen
Right descending pulmonary artery (RDPA)	Distance from lateral wall of right bronchus intermedius to lateral wall of RDPA (equivalent to the RDPA measurement on a chest x-ray)
True right descending pulmonary artery (true RDPA)	RDPA lumen diameter only *
True left descending pulmonary artery (true LDPA)	Lumen diameter distal to left upper lobe bronchus takeoff
Right ventricular free wall (RV wall)	Mid-ventricle *
Right ventricular lumen diameter (RV lumen)	Mid-ventricle *
Left ventricular free wall (LV wall)	Mid-ventricle *
Left ventricular lumen diameter (LV lumen)	Mid-ventricle *
IV septum bowing into LV	Yes or no
Left apical artery to corresponding bronchus ratio	Most apical bronchovascular pair
Hilar diameter (HD)	At level of right middle lobe bronchus takeoff
Hilar/Thoracic ratio	HD/Inner thoracic diameter (TD) measured at same level as HD
Landmarks used to standardize predictors of PH
Ascending aorta diameter (AA)	Widest diameter at the level of the PA measurement *
Descending aorta diameter (DA)	At same level as AA *

* Also see Figure 1