Ultrasound biomicroscopy (UBM) is ideally suited for phenotyping fetal mice for congenital heart disease (CHD), as
imaging can be carried out noninvasively to provide both hemodynamic and structural information essential for CHD
diagnosis. Using the UBM (Vevo 2100; 40Hz) in conjunction with the clinical ultrasound system (Acuson Sequioa C512;
15Hz), we developed a two-step screening protocol to scan thousands fetuses derived from ENU mutagenized pedigrees.
A wide spectrum of CHD was detected by the UBM, which were subsequently confirmed with follow-up necropsy and
histopathology examination with episcopic fluorescence image capture. CHD observed included outflow anomalies,
left/right heart obstructive lesions, septal/valvular defects and cardiac situs anomalies. Meanwhile, various extracardiac
defects were found, such as polydactyly, craniofacial defects, exencephaly, omphalocele，cleft palate, most of which
were associated with cardiac defects. Our analyses showed the UBM was better at assessing cardiac structure and blood
flow profiles, while conventional ultrasound allowed higher throughput low-resolution screening. Our study showed the
integration of conventional clinical ultrasound imaging with the UBM for fetal mouse cardiovascular phenotyping can
maximize the detection and recovery of CHD mutants.