Figure 2

Identification of septal, outflow tract, and aortic arch malformations using multi-embryo MRI (a – e') Images of transverse sections from 5 Cited2^-/- embryos obtained using the multi-embryo technique (a–e) compared with images from the same embryos obtained subsequently using the single embryo technique (a'–e'). (a, a') Section showing left and right atria and ventricles (la, ram, live, rave). The atria are separated by the primary atria septum (pas), which is deficient at its ventral margin creating an osmium premium type of atria septal defect (ASD-P). (b, b') Section showing a ventricular septal defect (VSD) in the interventricular septum (ivs). (c, c') Section showing double outlet right ventricle, wherein the ascending aorta (a-ao) and the pulmonary artery (pa) both arise from the right ventricle (rv). The aortic valve (ao-v) is indicated. (d, d') Section showing a right-sided aortic arch (ao-a) passing to the right of the trachea (tr) and the esophagus (es). (e, e') Section showing bilateral aortic arches (ao-a) forming a vascular ring around the trachea (tr) and the esophagus (es). Also indicated are the thymus (th) and the right superior vena cava (r-svc). (f – j) Serial transverse sections through a wild-type heart obtained using single embryo MRI, demonstrating corresponding normal structures, including the systemic venous sinus (svs), left superior vena cava (l-svc), pulmonary vein (pvn), descending aorta (d-ao), mitral and tricuspid valves (mv, tv), the secondary atrial septum (sas), left and right ventricular outflow tracts (lvot, rvot), pulmonary valve (pv), and arterial duct (ad) of the pulmonary artery. Scale bars = 635 μm for multi-embryo, and 317 μm for single embryo images; axes: d – dorsal; v – ventral; r – right; l – left.