Ultrasonic anatomy and pathology of the equine uterus

Abstract

The morphological and pathological status of the uterus in mares was evaluated using a linear-array ultrasound scanner, and the ultrasonic properties of the uterus were characterized. The uterus was examined each day in 16 mares, beginning at mid-diestrus. The uterus was recorded as having an ultrasonic morphology characteristic of diestrus (endometrial folds not distinguishable), estrus (prominent endometrial folds) or an intermediate stage (folds only moderately distinguishable). The number of mares with an intermediate or estrous image increased gradually between day −7 ( 2 14 mares; ovulation = day 0) and days −3 ( 11 16 ) and −2 ( 10 16 ) and then declined between days −2 and +1 ( 0 12 ). In another study, a large nonechogenic area (ejaculate) was visible in the uterine lumen immediately after mating in all of six mares. During the course of pregnancy diagnoses and hand-breeding, several pathological conditions of the uterus were first observed by ultrasound examination and confirmed by digital exploration of the uterus or at slaughter. Cysts contained nonechogenic material (fluid) and were usually compartmentalized. The purulent material associated with pyometria was relatively nonechogenic but contained echogenic spots. Mummified fetuses and remnants of fetal bones showed echogenic properties consistent with high tissue density. The results demonstrated that ultrasound technology provides a noninvasive form of visual access to the uterus to evaluate normal, morphological changes and to detect and study certain pathological processes.