Quantification of Initial Right Ventricular Dimensions by Computed Tomography in Infants with Congenital Heart Disease and a Hypoplastic Right Ventricle

Objective: To demonstrate the feasibility of using cardiothoracic CT for quantification of the initial right ventricle (RV) dimensions in infants with congenital heart disease (CHD) and a hypoplastic RV and to compare these measurements with those obtained in a control group with CHD without a hypoplastic RV. Materials and Methods: Initial RV dimensions, including RV volumes, RV/left ventricle (LV) volume ratios, atrioventricular valve annulus diameter ratios, and RV/LV length ratios based on CT data, were collected from 57 infants with CHD and a hypoplastic RV (hypoplastic RV group; age range, 1 day to 6 months) and 33 infants with tetralogy of Fallot (control group; age range, 1 day to 6 months) and compared between the 2 groups. The type of final surgery was also evaluated in the hypoplastic RV group over a follow-up period of 3-8 years. Results: The RV and LV volumes and lengths were successfully quantified in all 90 patients. The tricuspid valve annulus diameter could not be measured in cases showing muscular tricuspid atresia and double-inlet LV. The initial RV dimensions quantified by CT were significantly lower for the hypoplastic RV group than for the control group (p < 0.001). The types of final surgery performed in the hypoplastic RV group were univentricular repair in 46 patients, biventricular repair in 4 patients, or an indeterminate surgery in 7 patients. Conclusion: Initial RV dimensions in infants with CHD and a hypoplastic RV can be quantified by CT and are substantially smaller than those in infants with tetralogy of Fallot.