Radiology: Volume 254: Number 2—February 2010
Anand Devaraj, MD(Res), MRCP, FRCR Athol U. Wells, MD, FRCR, FRACP Mark G. Meister, MBCHB, MRCP, FRCR Tamera J. Corte, MBBS, FRACP Stephen J. Wort, MD, MRCP David M. Hansell, MD, FRCP, FRCR
Purpose: To test the reliability of potentially new computed to¬mographic (CT) indicators of pulmonary hypertension (PH) and to establish whether a combination of CT and echocardiographic measurements was more predictive of PH than either test alone.
Materials and Methods: The institutional review board approved this retrospec¬tive study; patient consent was not required. Seventy-seven patients undergoing right-sided heart catheteriza¬tion were examined. CT diameters of the main pulmonary artery, ascending aorta, and thoracic vertebra and cross-sectional area of the main pulmonary artery were mea¬sured. Segmental and subsegmental arterial diameters were recorded, and segmental artery size was compared with adjacent bronchus size by using a semiquantitative scoring system. The relationship between CT measure¬ments and mean pulmonary arterial pressure (mPAP) was tested with linear regression. Multivariate regression was used to establish a composite index of mPAP by using CT markers of PH with echocardiography-derived right ventri¬cular systolic pressure (RVSP). Post hoc logistic regres¬sion and receiver operating characteristic curve analysis were performed to test the diagnostic ability of the CT-echocardiography composite.
Results: The ratios of the diameter of the main pulmonary artery to the diameter of the ascending aorta (R2 = 0.45; P < .001) and of the cross-sectional area of the pulmonary artery to the diameter of the ascending aorta (R2 = 0.45; P < .001) correlated equally with mPAP. The ratio of the diameter of the main pulmonary artery to the diameter of the tho¬racic vertebra, the segmental arterial diameter, and the segmental artery-to-bronchus ratio were related to mPAP but did not strengthen correlations compared with the ratio of the diameter of the main pulmonary artery to the diameter of the ascending aorta alone. A composite index of the ratio of the diameter of the main pulmonary artery to the diameter of the ascending aorta and echocardiography-derived RVSP was more strongly related (R2 = 0.55) to mPAP and was more significantly predictive of PH than either measure alone.
Conclusion: A combination of CT and echocardiographic markers of PH is more closely related to mPAP than either test in isolation.