Background: Diseases causing increased pulmonary pressure will subsequently cause a dilation of the pulmonary arteries and right heart chambers.
Objectives: To assess the capability of computed tomography angiography and high resolution CT to diagnose and estimate the severity of pulmonary arterial hypertension as compared with standard means of right heart catheterization, echocardiography and pulmonary function tests.
Methods: The study included 38 patients with PHT who underwent CT angiography and HRCT as part of their routine evaluation. Diagnoses included: primary PHT (n=20), Eisenmenger syndrome (n=6), scleroderma (n=3), thromboembolic disease (n=3), and others (n=6). Mean pulmonary artery pressure was 58 mmHg (range 39-92 mmHg) by catheterization and peak systolic pressure 79 mmHg (range 40-135) by echocardiography. Findings for the diameters of the main pulmonary artery and its main branches, the ascending aorta, the right atria and ventricle as well as the position of the interventricular septum were compared with 22 chest CT scans of patients with no known clinical history of pulmonary hypertension, performed for other reasons (trauma, oncology follow-up) during the study period. Correlations were also calculated with recent right heart catheterization, echocardiography and pulmonary function tests of the study group.
Results: Mean main pulmonary artery diameter in the study group was 3.55 +/- 0.66 cm, pulmonary artery/ascending aorta ratio 1.2 +/- 0.29, right pulmonary artery 2.63 +/- 0.49 cm, left pulmonary artery 2.57 +/- 0.5 cm. All diameters were significantly different from the control group (P < 0.0001). Main and right pulmonary artery diameters correlated with the pressure measurement by echocardiography (P=0.001). Bronchial collaterals were found in 11 patients (30%). The position of the interventricular septum correlated well with the echocardiography study.
Conclusions: The size of the main pulmonary artery on CT angiography has a good predictive value regarding the severity of PHT.