CT assessment of main pulmonary artery diameter

The purpose of this study was to determine the normal range of the main pulmonary artery diameter (MPAD) by computed tomography (CT) in persons with normal pulmonary artery pressure, and then to evaluate the relationship of the diameter with age, gender, and body surface area (BSA).

Between October 2005 and June 2007, among patients who had previously undergone a contrast-enhanced thorax CT scan, 112 persons (47 females, 65 males) without pulmonary pathology were selected for the study. All patients had normal mean pulmonary artery pressure. The widest diameter perpendicular to the long axis of the main pulmonary artery was measured at the pulmonary artery bifurcation level. The outer limits of the contrast were used to determine vessel diameter.

Pulmonary artery diameters showed a homogeneous distribution; the CT-determined mean pulmonary artery diameter was 26.6 +/- 2.9 mm. The mean MPAD in males was 27 +/- 2.8 mm, and 25.9 +/- 3.0 mm in females. This difference was considered to be statistically significant (P = 0.048). There was a significant relationship between the MAPD and age and BSA (P = 0.043, P < 0.001).

The present study demonstrated that in individuals with normal pulmonary artery pressure, the upper limit of the MPAD is 32.6 mm and that MPAD is wellcorrelated with BSA.