A Doppler ultrasonographic study of cyclic changes of ovarian perfusion inthe Beagle bitch

Changes in intraovarian arterial blood flow were monitored by means of colo ur-coded and pulsed Doppler ultrasonography in Beagle bitches during the no rmal oestrous cycle (n = 11) and pregnancy (n = 3), and at PGF(2 alpha)-ind uced luteolysis (n = 4). The ultrasonographic findings were related to the reproductive stage of the bitch, as determined by vaginoscopical and cytolo gical criteria, and by the concentrations of oestradiol, LH and progesteron e in peripheral blood plasma. Colour-coded Doppler ultrasonography was used to visualize and estimate intraovarian vascularization, and pulsed Doppler ultrasonography was used to measure the arterial blood flow. The systolic and diastolic peak velocities, the end-diastolic velocity, and the pulsatil ity index and resistance index were calculated for quantitative analysis of the Doppler waveforms. Intraovarian perfusion increased gradually during p ro-oestrus. A marked enhancement of intraovarian colouring and blood flow v elocities, and a decline in the indices for pulsatility and resistance were observed in the preovulatory period. Maximum perfusion was observed at ovu lation and during the early luteal phase. Significant differences (P < 0.05 ) were detected for the values of all calculated Doppler parameters 2 days before and 2 days after ovulation. Intraovarian blood flow decreased gradua lly in accordance with luteal regression. Treatment with PGF(2<alpha>) caus ed a distinct decline in luteal activity and a concomitant reduction in int raovarian perfusion. The values of blood flow parameters found during the l uteal phase of pregnant bitches were comparable to those of the normocyclic bitches. Doppler ultrasonography of the intraovarian arteries in bitches p rovides complementary information about cyclic changes of ovarian function.