The 4D surface rendered image of atrioventricular valve obtained from reconstruction of RT 4D volume imaging in a fetus with partial atrioventricular septal defect. The 4D image can clearly show the two separate valve annuluses and two separate valves. The mitral valve with cleft (indicated by arrow). LA, left atrium; LV, left ventricle; MV, mitral valve; RA, right atrium; RV, right ventricle; TV, tricuspid valve