OP04.08: Direct 4D-MPI in fetuses with evolving cardiac compromise

Abstract

Modified myocardial performance index (Mod-MPI) is an accepted method of cardiac performance evaluation in children, adults and fetuses based on Doppler flow evidence of opening and closing of the AV and semilunar valves. We demonstrated 4D-MPI, based on analysis of STIC-acquired volume sets for direct visualization of opening and closing of the valves and assessment of the isovolumetric and ejection periods. We applied 4D-MPI to the evaluation of pathological cases with suspected or developing cardiac compromise and compared these results with Mod-MPI and normal 4D-MPI nomograms. Gravidae referred for evaluation of fetal pathologies with suspicion of cardiac compromise were examined with 2DUS parameters as indicated, including Mod-MPI. 4D-MPI was obtained in post-processing from saved STIC volumes. In multiplanar mode in post-processing, isovolumetric and ejection periods were measured according to valve status. 4D-MPI results were compared to conventional Mod-MPI. 30 healthy fetuses were examined to establish normal range of values for 4D-MPI at 24–32 weeks. MPI measured in both methods remained relatively stable during pregnancy. In 13 cases of evolving cardiac compromise (agenesis of ductus venosus with extra-hepatic connection-4, cardiomyopathy-2, SVT-2, diaphragmatic hernia-1, fetal anemia [before treatment]-2, pulmonary-venous shunt-1, CMV infection-1), conventional Mod-MPI and 4D-MPI showed similar results. The difference between them did not exceed ± 0.05 (clinically insignificant). 4D-MPI is useful for direct evaluation of fetuses with suspected cardiac compromise, and provided results comparable to those obtained with conventional Mod-MPI. 4D-MPI may form part of the 3D/4DUS exam performed on these fetuses.