Pulmonary Hypertension: ECG-gated 64-Section CT Angiographic Evaluation of New Functional Parameters as Diagnostic Criteria

Abstract

To evaluate, by using electrocardiographically (ECG)-gated multidetector computed tomography (CT), parameters such as right ventricular outflow tract (RVOT) systolic shortening and myocardial thickness and right pulmonary artery (RPA) distensibility, reported to be abnormal at echocardiography and/or magnetic resonance (MR) imaging in patients with pulmonary hypertension (PHT). The institutional review board approved the study and waived informed consent. Forty-five patients, 21 with PHT (group 1; mean pulmonary arterial pressure [PAP], 42 mm Hg) and 24 without (group 2; mean PAP, 16.5 mm Hg), who had undergone thoracic ECG-gated 64-section CT and right heart catheterization as part of their diagnostic work-up were included in this study. Two independent observers measured RPA distensibility and RVOT myocardial thickness, diameter, and cross-sectional area during systole and diastole. Their values were compared in both groups (Mann-Whitney U test). The area under the receiver operating characteristic (ROC) curve and Spearman correlation with mean PAP were also obtained. Interobserver agreement was good for all measurements (R > 0.8) except for systolic RVOT wall thickness. Median values of RPA distensibility, diastolic RVOT wall thickness, and systolic RVOT diameter and cross-sectional area were significantly different between groups 1 and 2. The largest area under the ROC curve was obtained with RPA distensibility (0.951; 95% confidence interval: 0.89, 1) also showing the closest correlation with mean PAP (r = -0.79; P < .0001). Among all parameters evaluated, RPA distensibility shows the best diagnostic value for PHT and could be useful for risk stratification.