Figure 1.

A, View of embryonic mouse heart in utero at 12.5 days (A, B). The division of the inflow tract is visible. Yellow boxes in (A) and (B) show sample volume locations for Doppler flow spectra from mitral orifice in (C) and from tricuspid orifice in (D). The large tics on the right side of the image indicate a 1-mm scale. (Images courtesy of Dr. Stuart Foster.) B, Ultrasound biomicroscopy imaging of the left ventricular outflow tract and AAo, with anatomical confirmation from MR imaging in the mouse. A, UBM image of a left parasternal longitudinal section (LL2) showing the left ventricular outflow tract and AAo, as well as the RA and RV in the far field and the RVOT in the near field. B, M-mode recording simultaneously demonstrates the dimensional changes of RVOT, AAo, and RA through cardiac cycles. C, MR image of the similar section as for the UBM image in A. D, UBM image of a right parasternal longitudinal section (RL5) showing the AO and AAo, with M-mode cursor line across the aortic cusps. E, M-mode recording at the level of the AO showing the movement of the aortic cusps. The arrow indicates the opening of the aortic cusps during systole. F, UBM image of a right parasternal longitudinal section (RL5) showing the AO and AAo, but with the M-mode cursor line at the level of AAo. G, M-mode recording of the AAo showing the overall excursion and dimension changes through cardiac cycle. IA, innominate artery; RCCA, right common carotid artery; RVOT, right ventricular outflow tract; Th, thymus. (Figure reproduced with permission from Zhou et al.²¹)