The right sided great vessels by cardiac multidetector computed tomography: normative reference values among healthy adults free of cardiopulmonary disease, hypertension, and obesity.

OBJECTIVE

We sought to derive normative reference values for the thoracic great vessels using multidetector computed tomography (MDCT) in a healthy normotensive non-obese population free of cardiovascular disease.

METHODS

Non-gated axial computed tomography (CT) of the chest has traditionally been used to evaluate normal great vessel anatomy for prognosis and management. However, non-gated axial chest CT cannot account for the obliquity, systolic expansion, and non-axial motion of the great vessels during the cardiac cycle and may misclassify patients as normal or abnormal for prognostic and management purposes. To date, normative reference values for double-oblique, short-axis great vessel diameters have not been established using current generation electrocardiogram (ECG)-gated 64-detector row MDCT. A total of 103 (43% women, age 51 +/- 14 years) consecutive normotensive, non-obese adults free of cardiopulmonary or great vessel structural disease, arrhythmias, or significant coronary artery disease were studied by MDCT. Individuals underwent examination for determination of end-diastolic (ED) pulmonary artery (PA) and superior vena cava (SVC) dimensions in double-oblique short axes for comparison with the ascending aorta and the right-sided cardiac chambers.

RESULTS

For right sided great vessels, the 5th to 95th interval was 1.89-3.03 cm for ED PA diameter and 1.08-4.42 cm(2) for SVC cross-sectional area. The pulmonary artery to ascending aortic (PA-to-Ao) ratio was 0.66-1.13. In multivariate analysis, the PA was significantly associated with weight, whereas the PA-to-Ao ratio was inversely associated with age. Axial PA measurements were significantly higher and PA-to-Ao measurements significantly lower than corresponding short axis measurements (P = .04 and P < .001, respectively).

CONCLUSIONS

This study establishes ECG-gated MDCT reference values for right-sided great vessel dimensions derived from a healthy population of individuals free of cardiovascular disease, hypertension, and obesity. The traditional axial PA-to-Ao discriminant value of 1 for pulmonary hypertension is a poor diagnostic tool because it encompasses normal patients and is negatively affected by age. Thoracic great vessels should be measured by CT in ECG-gated double-oblique short-axis for accurate quantitation. These data may serve as a reference to identify right-sided great vessel pathology in individuals being referred for ECG-gated MDCT imaging.