Computed tomography and magnetic resonance imaging
Until a few years ago, diagnostic imaging was limited to radiography (x-rays), ultrasound and endoscopy. Although these are still very useful diagnostic tools, there are now far more advanced diagnostic imaging methods, such as Computed Tomography (CT) and Magnetic Resonance Imaging (MRI), that are being more commonly used in rabbit medicine.
What is Computed Tomography (CT)?
CT, also known as CAT scanning, is a non-invasive imaging modality that uses x-rays to scan and create cross-sectional pictures of the animal which can be used to evaluate anatomy, function and pathology of many structures.
In rabbits, CT is particularly useful for viewing bony changes, such as those associated with advanced dental disease.
How is a CT scan performed?
A CT scanner is a large box-like machine with a short tunnel or hole running through the centre. Your rabbit will be placed on the examination table which then moves in and out of the tunnel.
The x-ray tube and electronic x-ray detectors are located opposite each other in a ring, called a gantry, and rotate around your rabbit to create the scan image.
The CT scan is controlled from a separate room, where the information is processed and from where the veterinary team can monitor your rabbit.
What is Magnetic Resonance Imaging (MRI)?
MRI is also a non-invasive imaging modality that scans the rabbit using a magnetic field to produce high-quality images of the animal which can be used to evaluate anatomy, function and pathology of many structures. Unlike a CT scan, it does not use any x-rays.
In rabbits, MRI is usually used to look at soft tissue structures, including organs within the body, and is especially useful when diagnosing brain tumours.
How is an MRI scan performed?
An MRI scanner consists of a box-like machine with a tunnel through the centre that is open at both ends. Your rabbit will be sedated or anaesthetised to keep it immobilised, then it will be placed onto a motorised table in the centre of the scanning tunnel. The table then moves inside the machine allowing the magnets to scan the body and create an image.
An MRI scan relies on a strong magnetic field to move around and react with different atoms within the body to create the image.
The operator is located in a different room, and the veterinary team will also monitor your rabbit from here.
MRI scanners are very noisy which is another reason why your rabbit is very likely to be sedated or placed under general anaesthesia, and it can take around half an hour to complete, during which time the rabbit must be very still to prevent blurring of the scan images.
What conditions are CT and MRI scans most useful for diagnosing?
- Tumours, especially brain tumours.
- Abscesses within the body/skull.
- Fluid within the tympanic bullae or the ear (inner and middle ear disease).
- Tumours within bone or the chest/abdomen.
- Central nervous disease, such as epilepsy.
- Assessing the vertebral column.
- Upper respiratory tract disease.
CT scanning is normally the technique of choice for assessing the skull and calcified structures, whereas MRI is mostly used for evaluating soft tissue.
Will my rabbit need sedation/general anaesthesia?
During the scanning process of both CT and MRI, your rabbit must stay totally still to get a good diagnostic image. Therefore, to ensure your rabbit is immobile during the procedure, your vet will need to either sedate or anaesthetise your rabbit. General anaesthesia is usually required, even in the most relaxed and well-behaved rabbit.
How long does it take to get the results?
The results of both CT and MRI scanning can be instant as the scan is shown on a screen as it is being taken. However, you may need to wait for a radiologist to view and assess the scans before any results are given to you.
How much does CT and MRI scanning cost?
CT and MRI scanning are now widely available through referral practices or visiting scanning companies. Although still expensive, now that they are more widely available and used, the costs have dramatically reduced in the last few years, making these services much more readily available to rabbit owners, many of whom may not have insurance.
Cost will vary significantly between veterinary practices and different areas of the country, but as an average figure, you should expect to pay anything between £800 and £1500 for a CT or MRI scan.
Will pet insurance cover the cost?
Generally, insurance companies will cover the cost of CT and MRI scans. As long as your rabbit does not already have pre-existing exclusions on its policy relating to the reason they are being scanned, and the scan has been recommended by a vet for a specific medical problem, there is no reason why your insurance company should not cover your rabbit for CT and MRI scanning.
You should call your insurance company before going ahead with any CT or MRI diagnostic scanning if you are in any doubt about your current cover. They will give you all the information you need about what is and isn't covered; they will also give you confirmation that you are covered.