Picture perfect

Often, it’s not possible for vets to be sure of the cause of a horse’s health problem by simply carrying out a physical examination. Especially when working with patients who can’t tell you what hurts or how things feel, knowing exactly what is going on to cause the symptoms that are being investigated means internal examination is often needed. Modern imaging techniques enable this without the unnecessary invasiveness of surgery, and developments in recent years mean that access to a range of methods has never been easier.

While radiography (X-rays) has been around for a very long time, over the past 20 years other types of imaging methods (or modalities) have been adapted from use in human medicine, and these have made a huge impact on vets’ abilities to diagnose health problems from illnesses to injuries, and, in particular, lameness.

Where it all began

The first imaging method, radiography, was developed in 1895 when the ability to look at bones and joints inside the body was discovered by German physics professor Wilhelm Röntgen. Since that time, the technique has, of course, become far more sophisticated. In addition, the use of ultrasound for soft tissues (such as tendons or intestines) and endoscopy to look inside body cavities with a camera have become common practice in equine veterinary medicine.

However, when these methods fail to produce the answers or detail needed to enable an accurate diagnosis, alternative approaches are required. This is where techniques such as nuclear scintigraphy (bone scanning), magnetic resonance imaging (MRI) and computed tomography (CT) can be beneficial.

While some X-rays and ultrasound investigation can be done on the yard using portable machines, when it comes to more sophisticated imaging techniques, your horse will need to visit a referral centre. This is because the sophisticated machines used are large and very complex.

Radiography (X-rays)

When taking a radiograph, a beam of X-rays is fired at the area of the body to be examined. Depending on the thickness and density of the body part involved, varying amounts of these X-rays are either absorbed by the tissue or pass straight through it to then be detected by a radiographic plate. A picture appears on the plate, with areas that have been exposed to a large amount of X-rays showing as darker and those where few X-rays have penetrated being lighter.

Radiographs are most useful for looking at the size, shape and density of bones and joints, and will usually be the first technique used for these areas. Diseases such as fractures, osteoarthritis and mispositioned bones (such as kissing spines or hoof imbalance) can usually be identified clearly on radiographs.

Did you know?

X-rays are radioactive and, while there is minimal risk to the patient, those taking radiographs receive significant cumulative exposure, and therefore must wear a special lead apron for protection.

Find out more about the different types of internal imaging techniques in April Horse&Rider – out now!