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 Magnetic Resonance Imaging (MRI) and Computed Tomography (CT), that are being more commonly used in rabbit medicine.
What is 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.
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 placed onto the motorised table in the centre of the tunnel. This moves inside the machine to create the scan with a small receiving device placed behind/around your rabbit.
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 can take around half an hour to complete, during which there must be minimal movement to prevent blurring of the scan images.
What is CT?
CT, also known as CAT scanning, is a non-invasive imaging modality that uses x-rays to scan the rabbit to 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.
Our sister practice Westway has a CT scanner, and we will happily refer you and your bunny to them if the need arises.
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.