An easy guide to MRI

Northwest Surgeons' MRI scanner

Magnetic resonance imaging (MRI) is becoming increasingly popular within the veterinary profession. 

Common examples of MRI use in animals include pets with spinal problems such as disc herniation and ishaemic myelopathy, brain abnormalities including tumours and chiari-like malformation and soft tissue troubles such as foreign bodies.

How does MRI work?

As the name suggests, the MRI machine is basically a giant magnet and has a very complex and clever way of working.  The most basic steps to understand MRI is as follows:

  • The patient is placed into the magnet
  • Water contained within the body is composed of hydrogen and oxygen atoms
  • A radio wave is sent in, which “spins” the hydrogen atoms of the body in a type of movement known as precession
  • Once the radio wave is turned off the patient emits signal, which is received to create an image

There are several types of images we can acquire to look for certain conditions and look at tissues differently to help with a diagnosis.  We look at all angles of a structure; dorsal, sagittal, transverse (top, bottom and sideways!)

Why do we choose to use MRI?

MRI is the gold standard for imaging the nervous system and allows us to see excellent detail and resolution of the brain and spinal cord.

Here at Northwest Veterinary Specialists, two of the registered nurses are currently training to operate the MRI machine.  Emma Lote RVN and Kelly O’Connor RVN have been working with MRI for just over 12 months and have gained a great deal of experience in this time.  They have completed a veterinary MRI course online from the American Association of Veterinary Radiologists (AAVR) and are currently building a portfolio of their cases they scan.

Emma and Kelly have recently attended an excellent 3 day VETCT course in Cambridge.  The course instructors were all veterinary specialists in diagnostic imaging and neurology and provided the nurses with an invaluable array of knowledge.

MRI procedure at NWVS

The patient having an MRI is admitted by the clinician and has a full vet check, either by our specialist anaesthetist or by the intern, who then consults with the anaesthetist.  Pre MRI procedures are carried out first, for example blood samples, radiographs, ultrasonography, etc.

All our MRI cases have a general anaesthetic as they need to be adequately restrained for the scans, which usually take 60 minutes but sometimes longer.  Once our patients are anaesthetised, we then position them in our MRI scanner and begin the scan.  We can monitor breathing using a capnograph, blood pressure and pulse rate from a distance.  Also the patient’s anaesthetic depth and pulse quality can be monitored by regularly checking them in-between scans. Read more about anaesthesia here.

Once the scan has finished, any post MRI procedures can be carried out such as CSF sampling, radiographs, urinary catheter placement or sending the patient to surgery for surgical correction of a disc herniation. The scans are either interpreted by our clinicians in house or may be sent to specialists externally for reporting.

Northwest Veterinary Specialists offers a full array of advanced diagnostic imaging modalities such as MRI and CT, giving you and your pet the very best options for diagnosis. Read about more successful stories here.

This blog was written by Kelly O’Connor RVN. Kelly is part of the advanced imaging team and runs the MRI scanner.