Equine Ultrasound: A Versatile Diagnostic Tool

Ultrasound in horses, also known as ultra sonography, is a diagnostic imaging technique that uses high-frequency sound waves to produce real-time images of soft tissues, muscles, tendons, and internal organs. It is widely used in equine veterinary medicine for diagnosing a range of conditions, particularly soft tissue injuries and reproductive health issues.

Common Uses of Ultrasound in Horses:

1. Soft Tissue Injuries:
   • Ultrasound is the gold standard for diagnosing injuries to tendons and ligaments. Common areas examined include:
     • Superficial Digital Flexor Tendon (SDFT)
     • Deep Digital Flexor Tendon (DDFT)
     • Suspensory Ligament and its branches
     • Inferior Check Ligament
   • It can detect tears, lesions, haematomas, abscesses, avulsion fractures, and inflammation and monitor the healing process.
2. Reproductive Ultrasound:
   • In broodmares, ultrasound is used for:
     • Pregnancy diagnosis: Early pregnancy detection can occur as early as 14 days post-breeding.
     • Monitoring fetal development throughout gestation.
     • Identifying twin pregnancies, which are high-risk in horses, allows for early management.
     • Evaluating the reproductive tract for conditions like ovarian cysts or uterine infections.
   • In stallions, ultrasound helps assess the reproductive organs, including the testes, for abnormalities such as cysts, tumours, or hernias where intestine may be found in the scrotum.
3. Abdominal Imaging:
   • Ultrasound is used to examine internal organs like the liver, kidneys, intestines, and spleen. It is particularly useful in diagnosing:
     • Colic: Ultrasound can help identify the cause of colic, such as intestinal displacement, impactions, enteritis, distentions or ileus (paralysis of the intestine).
     • Peritonitis: Inflammation or infection of the abdominal lining.
     • Kidney stones or other abnormalities in the urinary system.
4. Thoracic Ultrasound:
   • Used to assess the lungs and pleural space. It’s often employed to diagnose:
     • Pneumonia: Lung infections or inflammation.
     • Pleural effusion: Fluid buildup between the lungs and chest wall.
     • Lung abscesses or other masses.
5. Joint and Bone Imaging:
   • While X-rays are the primary tool for imaging bones, ultrasound is helpful in examining joint capsules, tendons, ligaments, and surrounding soft tissue structures.
   • In joint effusion or synovitis, ultrasound can visualize the amount of fluid or inflammation in the joint.
   • Ultrasound is particularly useful in identifying meniscal injury in the stifle.
   • Cartilage can also be assessed for thickness, fragments and erosions.
   • It can also assess periosteal reactions (bone surface inflammation) and help guide injections or drainage of fluid from joints or tendon sheaths.
6. Cardiac Ultrasound (Echocardiography):
   • This specialized form of ultrasound is used to evaluate the heart and diagnose cardiac conditions, including:
     • Valvular disease
     • Arrhythmias
     • Congenital heart defects
     • Pericardial effusion (fluid around the heart)
   • It helps assess heart function, chamber size, and blood flow, which is critical for athletic performance and overall health.

How Ultrasound is Performed:

1. Preparation:
   • The area to be scanned is typically clipped of hair to ensure good contact between the skin and the ultrasound probe. The skin is then rigorously cleaned with surgical spirit.
   • A gel is applied to eliminate air pockets and allow the sound waves to penetrate the tissues effectively.
2. The Procedure:
   • A transducer (ultrasound probe) is placed on the skin, and sound waves are sent into the body. These waves bounce back when they encounter different tissues, creating an image on a screen in real-time.
   • The veterinarian or technician moves the probe across the area of interest to capture detailed images from various angles.
   • Depending on the area being imaged, the horse may need to be sedated, though most procedures are painless and minimally invasive.
3. Digital Ultrasound:
   • Modern ultrasounds use digital imaging systems, which offer higher-resolution images and allow for detailed analysis. The results can be saved for monitoring changes over time, such as the healing of a tendon injury.

Advantages of Ultrasound:

• Non-invasive and painless, requiring no surgery or anaesthesia (except light sedation in some cases).
• Real-time imaging: The veterinarian can visualize the structures as they move or change, such as tendons sliding or a fetus developing.
• Excellent for soft tissues, which are not visible on X-rays.
• Portable: Ultrasound machines are portable, allowing for field use at farms or stables.

Limitations of Ultrasound:

• Limited bone imaging: Ultrasound is not ideal for diagnosing fractures or deep bone issues, as it primarily captures soft tissues.
• Depth limitations: While it’s useful for superficial structures, it may not penetrate deep into thick areas of the horse’s body, such as the pelvis or thorax.
• Image quality depends on the skill of the operator and the quality of the equipment, as well as the horse’s cooperation. At Stride Equine Vets we pride ourselves on having excellent modern equipment, giving high quality images.

Recovery and Follow-up:

• For tendon and ligament injuries, ultrasound is often used to monitor healing over time. Repeated scans allow the veterinarian to track changes and adjust treatment plans, including rest and rehabilitation programs.
• For reproductive cases, ultrasound is used throughout pregnancy to monitor fetal health and development.

Key Points:

• Ultrasound is a versatile diagnostic tool, especially for soft tissues and internal organs.
• It is non-invasive, providing real-time images without the need for surgery.
• Commonly used for diagnosing tendon and ligament injuries, pregnancy monitoring, and evaluating colic or abdominal conditions.
• It has limitations for deep structures and bone imaging, which require X-rays or other imaging techniques.

Ultrasound is a key part of modern equine veterinary practice, allowing for early detection and better management of a wide range of conditions.