The Use of MRI scanning in veterinary practise
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Neurological scanning
Brain
Since the introduction of MRI it has been found that brain tumours are more common than was previously thought.
Therefore this imaging modality has been of great value. Since most of the tumours are easily treated with surgery
animals can be saved. There is also the use in trauma, to assess and intracranial damage.
MRI scanning allows the Veterinary Surgeon to plan the surgery and assess the viability.
Other disorders in which it may be used for are:
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Hydrocephalus
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Cerebral hypoplasia |
Inflammatory brain disease |
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Case study 1
DSH cat with a fixed and dilated pupil. This pet was scanned to assess for optic nerve tumour however on examination
this cat was found to have a middle ear infection (red arrow). Following a course of antibiotics the cats eye returned to
normal and is now doing well.
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Spine
The use of MRI scanning has minimised the need for examinations such as myelography. This examination is less invasive
than general radiography and the tissue contrast for the spinal cord is very well visualised. Other uses include assessment
for paresis, prolapsed disc etc.
Case study 2
This is a basset hound with intermittent hind leg paresis. The MRI scan showed a slight prolapse of its lower lumbar discs,
with slight cord compression at some levels. Charlie is now undergoing a course of hydrotherapy and is doing well.
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Case study 3
This is a Rotweiller who was brought in with hind limb problems, the MRI scan diagnosed a prolapsed L7/S1 disc problem
and the dog is now undergoing treatment to minimise the problems.
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Orthopaedic
MRI for orthopaedic assessment in humans is now very well established and it has been proved to be very useful in many
situations, not only in the planning of complex surgery but also is helping prevent unnecessary surgery.
It is currently used to demonstrate articular cartilage, menisci, ligaments, tendons and other soft tissue structures.
MRI scanning could prove useful in the diagnosis of the following conditions:
1. Distension of a joint capsule
Synovial effusion, infection, haemathrosis, hypertrophy of synovial membrane and joint capsule fibrosis,
intra-articular neoplasia.
2. Altered joint space
Loss of joint space
Loss of articular cartilage e.g. DJD or infective arthritis
Widened joint space
Articular effusions, infection, haemarthrosis, intra-articular mass.
3. Calcified articular cartilage / OCD
4. Articular fractures
Avulsion fractures – you can assess the ligamentous involvement.
5. Intra-articular joint mice / Detached OCD lesions
6. Subchondral bone lesions
Erosive arthritides e.g. infective arthritis, RA, tumours invading subchondral bone, synovial sarcomata can destroy
the subchondral bone.
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Case study 4
3 year old Labrador with a history of swelling at the medial aspect of the stifle with a 1 month history of lameness.
Clinically the joint was stable and there was no suspicion of torn cranial cruciate ligament surgical planning was to
perform arthrotomy.
On MRI examination the cranial cruciate ligament was found to be ruptured (as demonstrated on the images below): |
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Other signs of this rupture are marrow oedema in the tibial plateau and the intercondylar notch.
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With these findings the surgical approach was reconsidered and the patient was booked in for cranial cruciate reconstruction.
At arthroscopy the surgical findings were the same as MRI findings.
Other findings confirmed at surgery:
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Torn medial meniscus
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Following surgery the Labrador has now made a good recovery and is full weight bearing on all four limbs.
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