Ultrasonography is the second most commonly used imaging technique in horses. It is often performed in practice using portable machines for the evaluation of the musculoskeletal system, especially tendons or for reproduction purposes, for example pregnancy checks.

As with our radiology equipment, we have a range of portable as well as hospital-based machines available to suit the individual application. Our state-of-the art hospital machines are ideal for scanning the more difficult areas such as the chest and abdomen of the horse for the evaluation of heart or lung problems or as part of our standard colic work-up.

Interpretation of ultrasound images requires excellent anatomical knowledge and a thorough understanding of imaging physics in addition to clinical expertise. Our multidisciplinary team works together to provide all this for your horse.

How does it work?

• Ultrasound uses transducers that send miniature sound waves into tissues that bounce back when they hit certain tissue borders – similar to an echo produced in the mountains.
• This echo gets registered by the transducers and transformed into a picture by the computer.
• Different tissues have different echogenic properties and these change with injury. This allows differentiation of healthy and pathological structures.
• Doppler ultrasound is a special technique that uses the properties of moving objects to evaluate blood flow. 

What does it show?

• Changes in the cross-sectional area and fibre alignment of tendons and ligaments
• Changes in the smoothness and integrity of bone surfaces
• Lesions in the menisci of the stifle
• Foreign bodies
• Problems with the blood flow in the heart
• Changes in the gut wall
• Changes to the lung surface 

When do we use it?

• In lame horses to assess the musculoskeletal system in the limbs but also the back and pelvis
• In colic cases to assess the intestines
• In poor performance horses
• In horses where we suspect a problem with the heart and chest
• To evaluate the extent and nature of wounds
• To guide injections, e.g. in the back

Transverse ultrasound image at the level of the palmar (hind) aspect of the cannon bone. At the top of the image the superficial digital flexor tendon is visible. Normal tendon tissue should be hyperechoic (white), but in this tendon there is a hypoechoic (dark) area consistent with a ‘core lesion’ of the tendon.

Ultrasound images of the medial meniscus of the left and right stifle in a horse. The image on the left shows the normal medial meniscus within the left stifle (dotted green line). The image on the right shows a lesion of the medial meniscus within the right stifle (dotted red line), which is small and shows centrally hypoechoic (black) areas (red arrow). Additionally, the proximal aspect of the tibia is irregular and shows some remodelling (orange arrow), consistent with osteoarthritis.

 Abdominal ultrasound image of a pony with severe colic. Several distended amotile loops of the small intestine were found with a diameter up to 5 cm (blue line). During surgery a volvulus (twisting of the intestine around itself) of the small intestine was found and corrected.