Imaging
Computed Radiography
The Equine Centre uses the latest computed radiography system to obtain high quality x-rays of all parts of the horse. We have two roof mounted x-ray tubes and a powerful generator that allows images to be obtained even in large horses. Most radiographs can be taken standing in sedated horses. For example we are able to perform x-rays of the shoulder standing. We also have the facilities and expertise to perform x-rays of the pelvis under general anaesthesia.
Computed Tomography (CT, CAT scan)
CT scanning uses x-rays to create a 3-dimensional image of the area of interest. This greatly increases the information obtained and is therefore far more sensitive for identifying both bony and soft tissue lesions, compared with conventional (2D) xrays. The Equine Centre has access to an advanced CT system that was recently purchased by the Veterinary Hospital. We can currently image foals and small ponies with this system and are in the process of modifying it to allow imaging of large horses.
CT is best suited for imaging of the head including diseases of the teeth, sinuses and nasal cavity, as well as bone and soft tissue problems in the lower limbs.
Myelography
Ultrasonography
Ultrasound is used primarily for imaging soft tissues although it is also useful for bone surfaces. It therefore combines well with x-rays for investigation of limb problems. It can be used to investigate problems of bones in areas where obtaining good quality x-rays is problematic, such as the pelvis and spine. We also use ultrasound to investigate heart, lung and gastrointestinal conditions. Nearly all horses referred for colic investigation undergo ultrasound examination of the abdomen.
Doppler Ultrasonography
Scintigraphy (Bone Scan)
Bone scanning is the most sensitive technique for detecting bone injury available for horses. It involves the injection of a radiopharmaceutical which is taken up by areas of bone with increased turnover. A large camera (gamma camera) is used to image the horse and this detects 'hot spots' where there is injury.
The University of Melbourne Equine Centre Scintigraphy Unit has a proud, nine year history of producing extremely high quality images. Our qualified and very experienced nuclear medicine staff keep this sophisticated and sensitive equipment running smoothly and accurately. Over the years we have accumulated a vast database of images with which we can compare each new case. We have just updated our equipment to use the most advanced software available worldwide.
We are able to perform scans on all areas of the body from the feet to the head. Scintigraphy is especially useful for cases where the source of the lameness is difficult to localise, where the site of lameness has been identified but there are no changes on radiographs, where multiple sites of lameness are suspected and for problems of the spine, pelvis and sacroiliac regions.
The horse is usually admitted the day before the scan and depending on results the horse is able to go home 24 hours post scintigraphy.
Magnetic Resonance Imaging (MRI)
MRI is the most advanced imaging technique available. It allows three dimensional imaging of both soft tissue and bone all at once. For horses it is most valuable for imaging problems within the foot because ultrasound imaging in this region is limited by the difficulty of penetrating the hoof.
Many horses have lameness that can be localised to the foot with nerve blocks but radiographs are normal or show changes for which the significance is unknown. MRI is extremely valuable in these cases as the bones can be imaged in far greater detail, as well as the soft tissues. Common problems that occur within the foot that require MRI for a diagnosis are deep digital flexor tendon injuries, injuries to the collateral ligaments of the coffin joint, problems with the ligaments of the navicular bone and navicular bone injuries themselves.
MRI systems are divided into high-field and low-field systems based on the strength of the magnet. In general the stronger the magnet (high-field) the more detailed the image quality. At the Equine Centre we have the only high-field MRI system in Australia for imaging horses. The advantage of low-field systems is that the horse can be imaged standing and sedated. Disadvantages are the smaller area that can be scanned and the lower resolution which makes subtle changes more difficult to identify. High-field systems require general anaesthesia but can image larger areas and provide better resolution.
The high-field system at the University of Melbourne Equine Centre can image the foot and pastern of most adult horses of the larger breeds.