Fig. (2) Definition of the correct plane for measuring the diameter of the pulmonary trunk (tp). Note the orientation of the original sections (os). The inlay shows the virtual section plane (vs), which was defined to cut through the volume data perpendicularly to the longitudinal axis of the pulmonary trunk. aa = ascending aorta; da = ductus arteriosus; dao = descending aorta. Scalebars = 200 µm.