Page 176 - The Veterinary Care of the Horse

• for detection of foreign bodies and abscesses within tissues

• to detect areas of fibrosis within muscles.
VetBooks.ir Other uses of ultrasonography include:

• monitoring the reproductive cycle of mares for breeding purposes
• identification of reproductive problems

• monitoring foetal development

• investigation of heart disease

• evaluating the eye

• investigation of respiratory disease especially in foals
• imaging the abdomen: for example, distended loops of intestine may be seen with a

bowel obstruction; liver biopsy is often performed using ultrasound to aid identification

of the organ and accurate biopsy of the tissue
• investigation of bladder problems.

Preparation of the patient

In order for good images to be obtained, there must be excellent contact between the

ultrasound probe and the skin of the horse. Dirt, scurf, scabs, hair and air all spoil the quality
of the image. The hair is clipped with a fine blade and the area is then washed with an
antiseptic scrub and rinsed carefully with water. Horses with greasy skin and a coarse hair

coat may require a further close shave. An acoustic coupling gel is then applied to aid contact
between the probe and the skin and time is allowed for it to soak in properly. With fine-

coated animals it is sometimes possible to obtain diagnostic images without clipping the hair.
For investigation of tendon and ligament injuries, it is important that the horse is bearing

weight on the limb during the examination for meaningful images to be obtained. Fractious
patients are sedated for the procedure in the interests of safety of the person carrying out the

examination, the expensive equipment and the horse itself. In ideal circumstances, the horse
will be examined in stocks in a room with subdued lighting.

The procedure

The region of interest is thoroughly and systematically examined. A standard system has
been developed for evaluation of the lower limb between the knee or hock and the fetlock. In

the forelimb, it is divided into seven regions and each of these is scanned in two planes. The
transverse scan detects any change in cross-sectional size, shape or echogenicity of the