Three-dimensional magnetic resonance imaging for the study of ovarian function in a bovine in vitro model.

Three-dimensional magnetic resonance imaging coupled with maximum intensity projection display, a technique usually reserved for magnetic resonance imaging angiography, is useful for the study of ovarian follicular growth. The ovaries of 19 cows were examined each day by transrectal ultrasonography. From these data, the precise phase of the ovarian cycle was determined and cows were ovariectomized on day 3 of wave one (n = 5), on day 6 of wave one (n = 4), on day 1 of wave two (n = 4), >/= 17 days after ovulation (n = 5), and on the day of ovulation (n = 1). The excised ovaries were examined by magnetic resonance imaging using a fast imaging with steady state precession imaging sequence with maximum intensity projection reconstruction, displayed as a cine-loop of the ovaries rotating in space. This provided the clearest view among the three principal three-dimensional steady state data acquisition approaches tried; the follicles and other ovarian structures could be distinguished unambiguously. Results from the bovine model indicate that the acuity of the three-dimensional fast imaging with steady state precession technique has potential application in in vivo intravaginal imaging in women for studying normal and pathological ovarian function.