How can MRI help your horse?
During a standard lameness investigation it is very common practice for your vet to carry out a series of nerve and joint blocks, in order to discover where the pain, that is causing your horse to be lame, is coming from.
Once the lameness has been localised to a specific area ( e.g the foot or fetlock region) then x-rays are taken and /or an ultrasound scan is performed in order to try and make a specific diagnosis. X-rays are used to look at bony structures while ultrasound is useful for looking at soft tissues. It is not uncommon for no definitive diagnosis to be made from these imaging processes. In addition to this there are areas of the limb where it is very difficult, if not impossible, to see all the structures within that area (such as the foot or proximal suspensory ligament region)
This is where the use of MRI comes into it’s own, enabling us to make a quick, safe and accurate diagnosis.With the right case selection MRI can save time, money and reduce the worry of the owner, of not knowing exactly what is wrong.
Early Diagnosis
Once nerve blocks have been performed to confirm the location of the site of pain, and if x-ray and/or ultrasound do not provide a diagnosis then MRI can be used to make a diagnosis. This means clients don’t have to wait several months to see if rest or a non-specific treatment has worked. Waiting can cost money, be frustrating and not provide a conclusion, this is where an MRI scan may be carried out.
Safe
Because the Hallmarq system enables us to scan horses/ponies under standing sedation, there is no anaesthetic risk. There is no risk to the horse from the MRI scanner itself (unless it has a pacemaker!)
Accurate
The use of MRI enables us to image lots of structures that we can’t see with x-ray/ultrasound. This means that we are more able to give a definitive diagnosis and direct our treatments more specifically on a case by case basis. It should also enable us to better predict likely outcomes (prognosis) for individual cases.
With more widespread use of MRI for the diagnosis of lameness in horses/ponies more cases have a definitive diagnosis, treatments can be tailor made, outcomes better predicted and in many cases outcomes improved.
A common reason for performing a standing MRI scan is for cases of palmar foot pain (horses/ponies with lameness that is localised towards the back of the foot). MRI will help to differentiate between many possible causes of pain in this region. Some of these cases carry a good prognosis and warrant appropriate treatment while other cases don’t.
Published studies have shown that medicating the Navicular Bursa (the small bag of fluid that sits between the back of the Navicular Bone and Deep Digital Flexor Tendon) can give results so long as there is no associated changes to the flexor (back) surface of the Navicular Bone or the DDFT. if changes are present then prognosis is poor.
Not all cases of lameness require an MRI scan but cases that may fit the criteria to be suitable for a scan include:
- Chronic (long standing) lameness that has been localised to the foot or the lower limb by nerve blocks
- Radiographs are negative or equivocal
- Nuclear Scintigraphy (bonescan) is being considered or has been performed and was negative
- The area is difficult/impossible to scan with ultrasound (e.g the foot/proximal suspensory region)
- Penetration injuries that require a rapid and accurate diagnosis (e.g treading on a nail)
- After acute (sudden) onset lameness during exercise
- To monitor treatment and healing and so help with the rehabilitation process
MRI cases should be booked into our hospital by the vet treating your horse. We welcome cases from within our own practice and from referring vets.
