Anatomic T2-weighted fast spin-echo rapid acquisition with refocused echoes images of imprinting control region pregnant mouse at embryonic day 17.5 show several fetuses (F) and their placentas (arrows). Regions of interest (dotted lines) were drawn on the basis of anatomic images for each type of tissue: (a) Region of interest placement in maternal liver (white dotted line) and (b) region of interest placements in the placenta (black dotted line) and fetal liver (white dotted line).