Reference Values for Normal Pulmonary Artery Dimensions by Noncontrast Cardiac Computed Tomography: The Framingham Heart Study

OBJECTIVES: 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: In 3171 men and women (mean age, 51±10 years; 51% men) from the Framingham Heart Study, a noncontrast, ECG-gated, 8-slice cardiac multidetector 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 valve surgery.

RESULTS: The mean mPA diameter in the overall cohort was 25.1±2.8 mm 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 sexes but decreased with increasing age (range, 0.82-0.94), 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.

PMID: 22178898

Jacobo Kirsch

Associate Center Director, Imaging Institute
Cardiopulmonary Imaging, Section Head
Cleveland Clinic Florida
Weston, FL
Posted in Computed Tomography and tagged , , , , .

3 Comments

  1. This was a much needed study! PA size is an ongoing question which never had an answer. These reference values will serve well the population of congenital heart disease and chronic pulmonary hypertension.

  2. A useful cohort from EKG-gated studies, although a non-gated standard measurement of 3cm is already well-known from another MGH publication. A caveat is that these were true axial images, not short-axis images of the PA, which introduces some measurement error as it does not represent the “true diameter” of the artery. Many of us would agree the PA to aorta ratio of 1 is a helpful clinical tool in daily practice.

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