P1120987

1 Ultrasonography in the mar

1.1 Technique of ultrasonography in the marę

In mares the uterus and ovaries are examined by transrectal ultrasonography. For this purpose the ultra-sound probe is introduced into the caudal rectum.

In order to keep the probe hygienic and to protect it firom moisture it is preferable to puli a plastic sleevc over the probe. The space between the scanning win-dow of the probe and the plastic sleeve must be filled with gel to exclude any air bubbles which cause undesi-rable reflections and thus affect the image ąuality. It is not necessaiy to apply any coupling gel between the plastic sleeve and the rectum, sińce he rectum’s natural contractility and moist contents both provide favorable conditions for the exclusion of air between the probe’s scanning surface and the rectal wali. Many veterinarians introduce the unprotected probe into the rectum.

The procedurę of ultrasound examination of the uterus and ovaries is similar to that of a rectal examination (Fig. 1.1). Control and handling of the marę are also the same. Before the genital organs are scanned they are palpated in the usual manner thereby facilitating the speedy location of the organs and the correct position-ing of the probe to ensure a swift and accurate examin-ation. During the leaming period of ultrasound examin-ations it is also helpful to compare the familiar palpable structures to the “new” images seen on the screen. This

allows for the recognition and identification of the genital organs and their characteristic ultrasonic pat-tems.

Feces and fecal gas bubbles hinder the transmission of ultrasound waves. The absorption of sound waves by fecal matter lying between the probe’s scanning window and the rectal wali will result in the appearancc of black stripes in the depth of the image. The rectum must therefore be evacuated and the probe then introduced through the anus. The probe’s scanning window is di-rected ventrally while it slides cranially along the rectal floor. During the examination the probe is covered dor-sally by the examiner^,s hand and manipulated with the fingers. With inereasing experience it is frequently possible to determine the position of organs and the probe’s orientation inside the pelvis by recognizing typical images on the screen. It is usually not necessary to manually position the organs in preparation for an ultrasound examination.

The urinary bladder is the First ultrasonically striking organ encountered after passing the probe through the anus. The neck of the bladder widens over the cranial pelvic edge to join the body of the bladder (Fig. 1.2). The echogenicity of mares’ urine can vary greatly. The ultrasonic image varies from almost anechoic to strongly echoic in the case of very viscous urine (Fig. 1.3). Turbulently moving reflexions can freąuently be detected inside the bladder’s fluid content.