Diagnostic Imaging for horses
The AHT’s diagnostic imaging facilities for horses
- X-ray with computerised radiography
- Logiq E Ultrasound Machine by IMV Imaging
- Hermes Nuclear Scintigraphy system
- Standing Hallmarq MRI system
- High field GE Signa Echospeed MRI system for assessment under general anaesthesia
Equine radiography is an imaging modality that is still an essential component of a horse’s orthopaedic diagnostic evaluation. It is made possible by the production of useful, high-energy photons (x-rays) that pass through the area of interest and are used in the production of the resultant image on the specially sensitised film screen.
Our powerful system provides excellent quality images of nearly all parts of the horse, including areas, such as the back or the shoulder, that are difficult or not possible to image with portable machines.
In the computed radiography system, radiographs acquired on a cassette are read by a computer and displayed on a screen. Radiographs can be manipulated to enhance image quality and are stored electronically.
Magnetic resonance imaging (MRI)
MRI provides detailed 3-dimensional information of both soft tissues and bones and can provide diagnosis when the results of radiography and ultrasonography do not explain the lameness. During an MRI examination only a small area can be evaluated and therefore it is important that the lameness is localised as much as possible. High-field MRI is performed with the horse under general anaesthesia and provides more detailed information than the low-field system. It is very useful in horses with mild lameness related to the foot or fetlock, when relatively mild lesions are expected. Low-field MRI is performed under standing sedation and it is possible to examine the limbs up to and including the carpus (knee) and the hock.
MRI is an imaging technique that uses a strong magnet to create detailed images of bones and soft tissues within a patient. MRI is a non-invasive technique used widely in humans, and increasingly in horses for detection of damage to a wide range of tissues. MRI is particularly useful for orthopaedic injuries affecting bones, joints and soft tissues. Unlike x-rays, MRI does not require the use of ionising radiation. MRI is very versatile in the ability to provide images sliced in many planes, and is capable of producing 3-dimensional images in a variety of orientations.
We routinely scan horses with proximal metacarpal and metatarsal pain, and are detecting damage to single lobes of the suspensory ligament, osseous changes or interosseous ligament pathology. MRI of horses with fetlock region pain may show joint and osseous damage, pre-fracture pathology, distal sesamoidean ligament or intersesamoidean ligament abnormality. MRI of horses with pain localised to the carpus or tarsus has allowed us to identify subtle joint or intertarsal/intercarpal ligament abnormalities.
We have more than 10 years experience interpreting equine MR images using high and low systems. We have validated MR images in horses against post-mortem, histology, radiography, ultrasonography and scintigraphy so can provide a clinical service based on real facts. We are regularly consulted on MRI image acquisition and interpretation by equine clinics worldwide and have published and presented more papers on equine MRI than any other equine practice.
Scintigraphy (bone scanning)
Equine scintigraphy (bone scan) involves injection of a radioisotope and shows areas in the horse’s skeleton where there is increased activity of the bone, which may indicate lesions. Horses are sedated for the examination. Images are acquired by a camera and then displayed on a computer screen, showing abnormal areas as ‘hot spots’. Indications for scintigraphy include lameness that cannot be localised using nerve and joint blocks, multilimb lameness and poor performance.
Scintigraphy can detect bony changes much earlier than radiography; therefore it is particularly useful in competition horses to diagnose stress-related bone injuries. Besides detecting lesions not identifiable by other imaging techniques, Scintigraphy can also help to establish the clinical significance of lesions detected by radiography, ultrasonography or MRI.
Both our gamma cameras are designed to enable quick and efficient acquisition of scintigraphic images of any area of the axial and appendicular skeleton in the standing horse, meaning no general anaesthesia is required. Research at the Equine Centre has pioneered its use, which has revolutionised equine veterinary practice.
Ultrasonography is a useful tool to diagnose and monitor healing of lesions in horse’s tendons, ligaments, joints and muscles. A probe emits ultrasonographic waves, which are then reflected by the tissues back towards the probe, where they are detected. The ultrasonographic waves are reflected differently depending on what tissue structure they contact and it is these differences that are used to create an image where soft tissue structures and the surface of bone can be visualised.
In addition to commonly examined regions in the limb, ultrasonography can also be used to evaluate the horse’s neck, back and the pelvis, including areas that are difficult to image with other diagnostic imaging techniques.