Reference Values for Normal Pulmonary Artery Dimensions by Noncontrast Cardiac Computed Tomography

Abstract

Background Main pulmonary artery diameter (mPA) and ratio of mPA to ascending aorta diameter (ratio PA) derived from chest CT are commonly reported in clinical practice. We determined the age and sex-specific distribution and normal reference values for mPA and ratio PA by CT in an asymptomatic community-based population. Methods and Results In 3171 men and women (mean age 51 ± 10 years, 51% men) from the Framingham Heart Study, a non-contrast ECG gated eight-slice cardiac multi-detector CT was performed. We measured the mPA and transverse axial diameter of the ascending aorta at the level of the bifurcation of the right pulmonary artery and calculated the ratio PA. We defined the healthy referent cohort (n=706) as those without obesity, hypertension, current and past smokers, chronic obstructive pulmonary disease, history of pulmonary embolism, diabetics, cardiovascular disease, and heart valvular surgery. The mean mPA diameter in the overall cohort was 25.1 ± 2.8mm and mean ratio PA was 0.77 ± 0.09. The sex-specific 90th percentile cutoff value for mPA diameter was 28.9 mm in men and 26.9 mm in women and was associated with increase risk for self-reported dyspnea (adjusted odds ratio 1.31, p=0.02). The 90th percentile cutoff value for ratio PA of the healthy referent group was 0.91, similar between gender, but decreased with increasing age (range 0.82 to 0.94), though not associated with dyspnea. Conclusions For simplicity, we established 29 mm in men and 27 mm in women as sex-specific normative reference values for mPA and 0.9 for ratio PA.

The pulmonary artery in patients with Marfan syndrome: a cross-sectional study

“…In the literature, most of the papers that have addressed upper normal values for the pulmonary artery have considered only the trunk of the pulmonary artery, and among those performed using axial imaging, 4,[17][18][19][20][21] only four included an adequate number of subjects ( Table 4). The upper normal limit for the trunk diameter of the pulmonary artery, defined as mean diameter + 2 SD, was clearly larger in two of the studies 18,19 than in the other two, 17,21 32.4 and 33.2 mm vs. 29.6 and 30.1 mm, respectively. This may be explained by the difference in slice thickness, 10 mm vs. 5 mm and 2.5 mm.…”

“…In the largest study, the so-called Framingham study, 21 the 706 healthy persons studied had a mean age 6 years greater than that of our study population (45.6 vs. 39.6 years), and CT was performed with half the slice thickness. Cutoff values for pulmonary artery diameters were given as 90th percentile (29 mm for men and 27 mm for women), but when given as mean + 2 SD for the whole population, the result (30.1 mm) is quite similar to that reported by Bozlar et al (29.6 mm).…”

“…We therefore believe that normal values for the diameter of the pulmonary artery measured using axial imaging are now well documented. 17,21 However, reliable values for the normal root diameter are not yet available, and may be difficult to obtain given the asymmetry of this part of the vessel.…”

The role of computed tomography in the diagnosis of acute and chronic pulmonary embolism

“…Regarding the size of the main pulmonary artery at the level of pulmonary artery bifurcation, a variety of "upper limits" of normal diameter have been published (91,92). A practical rule-of-thumb is the diameter ratio of the main pulmonary artery to that of the (normal) aorta measured on CT. A ratio >1 strongly suggests pulmonary hypertension, with 92% specificity and 96% PPV (93).…”

Complications of pulmonary hypertension: a pictorial review

“…In patients without interstitial lung disease, the upper limit of the pulmonary artery diameter for males is 29 mm and 27 mm for females. 3 In patients with interstitial lung disease, the pulmonary artery may be dilated without the corresponding increase in pressure. 4 Dilated pulmonary arteries can cause extrinsic compression on the left main stem coronary artery (Figure 1).…”