Pediatric cardiac MRI: anatomy and function

Visceroatrial situs: There is visceral and atrial situs inversus (left-sided liver and right-sided spleen in Fig. 1a, right-sided morphologic left atrium [LA] in Fig. 1b,d and e receiving pulmonary veins, left-sided SVC in Fig. 1d entering left-sided morphologic right atrium [RA], not shown in this figure. The IVC also entered the left-sided morphologic RA). Ventricles: D-loop (The morphologic right ventricle [RV] is located to the right of the morphologic left ventricle (LV) on Fig. 1a [short-axis], and Fig. 1b [four-chamber view]. Note moderator band within right-sided RV, and smooth septal surface of the LV) Great arteries: D-malposition (aortic annulus to the right of pulmonary annulus, in Fig. 1c and d) Atrioventricular connection: Discordant (LA connected to RV and RA connected to LV) in Fig. 1b,c and e Ventriculoarterial connection: Discordant (RV connected to AO, and LV connected to PA) in Fig. 1c and f Associated anomalies: (1) Tricuspid regurgitation with severe right ventricular and left atrial dilatation (Fig. 1b and f). Arrow in Fig. 1b shows the tricuspid regurgitant jet within the LA. (2) Pulmonary atresia, status post LV to pulmonary artery conduit (Fig. 1c) Physiology: Corrected transposition in situs inversus, with poor function of the systemic RV secondary to severe tricuspid regurgitation Treatment decision: The patient underwent tricuspid valve replacement. Fig. 1e and f are post-surgical images showing the artifact arising from the prosthetic tricuspid valve (arrow), with improvement in RV and LA dilation.