Can the ovarian blood flow assessed by power Doppler be used in the bitch for monitoring ovulation and luteal phase?

The haemodynamic changes in the ovary of non-pregnant bitches during oestrous and diestrous phases were characterized by power Doppler (PD) to verify the relationship of the perfusion parameters with ovulation and luteal function assessed by serum progesterone concentrations. Eight healthy German Shepherd bitches were recruited in this study. Intraovarian vascularization was examined by Colour Doppler (Duplex mode) and PD throughout the oestrus cycle, at daily intervals from the onset of proestrus to the first day of cytological diestrous and then every three days until the end of diestrous. During the early proestrous and late estrous phase, the pixel number increased progressively from 180 ! 59.9 to 3303 ! 144.4, respectively. In particular, this increment was significantly higher (p < 0.05) just before ovulation (708 ! 87.4) and soon after ovulation (3227 ! 217.1). Afterwards, the pixel numbers decreased progressively until the end of observations when the number of pixel returned to basal values observed during the proestrous phase (155 ! 22.7). The mean blood progesterone concentrations and pixel number showed a direct positive correlation. The results of our study show that the PD is valid method for studying the vascularization of the ovary during the oestrous cycle in the bitch. In particular, this technique could provide another useful method for determining more precisely the time of ovulation and monitoring luteal function in the bitch