When your pet needs advanced imaging, it can feel overwhelming to understand the differences between CT (pictured) and MRI. Both play important roles in veterinary medicine, and in many cases either could be used. The choice often depends on the disease process, your pet’s health and the type of information needed.
Scan time and patient comfort
MRI scans take longer (30–90 minutes) and are very sensitive to movement, so patients need to have a general anaesthetic.
CT scans are much faster (seconds to minutes). Sometimes light sedation is enough, although anaesthesia is usually recommended for best results. CT can image large areas quickly, such as the whole chest and abdomen, making it especially useful in emergencies. For example, it is the preferred option for assessing fractures or checking lung problems after an accident.
When MRI isn’t suitable
MRI uses a strong magnet. Pets with certain metal implants may not be safe candidates, or the images may be distorted. For example, a hip implant won’t affect a brain scan, but it would interfere with imaging of the pelvis. Pets with pacemakers cannot have MRI at all, as the magnet could disrupt the device. MRI is less suitable for structures that move, such as the chest.
What MRI does best
MRI is excellent for soft tissue detail, making it the best option for:
- Neurological conditions such as seizures, brain tumours, intervertebral disc disease (IVDD), spinal cord compression and meningitis
- Soft tissue tumours
- Musculoskeletal injuries involving tendons, ligaments and muscles.
What CT does best
CT excels at showing bone, mineralised tissue, lungs and blood vessels. It’s particularly useful for:
- Fractures and luxations
- Nasal disease, sinus problems and dental conditions
- Lung disease and pulmonary metastases
- Oncologic staging, including lymph node involvement and vascular invasion
- Pre-surgical planning with 3D reconstructions
- Vascular imaging (e.g. portosystemic shunts, vascular ring anomalies, cardiac disease).
Comparing specific areas
- Brain and spine: MRI is the first choice, although CT (and CT myelograms) can help identify spinal disc disease and pituitary tumours.
- Joints: MRI shows ligaments and tendons; CT shows bone in exquisite detail.
- Nose and sinuses: CT is best for chronic rhinitis, foreign bodies, or bone cancer. MRI may be the better choice if there are also brain signs, e.g. seizures.
- Ears: CT highlights bony changes in the middle ear, while MRI shows nerves and soft tissue changes.
- Thorax and lungs: CT is superior.
- Abdomen and cancer staging: CT allows thorough whole-body assessment.
- Specialist uses: CT urography helps diagnose urinary tract abnormalities, and CT 3D reconstructions support surgical planning.
Sometimes both are needed
In some cases, the most complete picture comes from using both modalities. For example, with spinal fractures, MRI will show whether the spinal cord is damaged, while CT will provide precise details for surgical stabilisation.
Key takeaway
CT and MRI are not competing technologies but complementary tools. Your veterinary team will recommend the one that best answers the clinical question for your pet. In some situations, combining both offers the clearest roadmap for diagnosis and treatment.
To find out more about CT* and MRI services offered at AREC, visit our Imaging webpage for availability, prices and how to refer.
Also read our article How MRI enhances emergency and surgical care in veterinary medicine to find out more.
* CT available from October 2025.
