Atlantic Veterinary Internal Medicine & Oncology (AVIMO)

Understanding Imaging: X-rays, Ultrasound, CT, and MRI

When your pet is sick or experiencing unexplained symptoms, your veterinarian may recommend imaging to help better understand what’s happening inside their body. Just like in human medicine, different imaging tools give us different kinds of information—and each one plays a unique role in diagnosing illness.

Here’s a quick overview of the most common imaging techniques used in veterinary internal medicine and how they differ.

X-rays (Radiographs)

X-rays are one of the most commonly used imaging tools in veterinary medicine. They create still images of dense structures inside the body, such as bones and certain organs.

Best for:

• Checking for broken bones or arthritis

• Evaluating the size and shape of the heart or lungs

• Detecting bladder or kidney stones

• Identifying large tumors or abnormal gas patterns in the abdomen

Quick and widely available, X-rays are usually the first step in imaging but may not provide enough detail for soft tissue structures.

Ultrasound

Ultrasound uses sound waves to create real-time images of your pet’s internal organs. It allows us to see inside soft tissues and detect things that X-rays might miss.

Best for:

• Examining the liver, kidneys, spleen, bladder, intestines, or pancreas

• Guiding biopsies or fluid sampling

• Detecting fluid buildup or abnormal masses

• Monitoring heart function (echocardiogram)

Ultrasound is non-invasive and painless, though mild sedation may be recommended to help your pet stay still.

CT Scan (Computed Tomography)

CT scans use X-rays combined with computer technology to create detailed, cross-sectional images of the body—like slices through a loaf of bread. This provides a 3D view that allows for better visualization of complex structures.

Best for:

• Investigating nasal or sinus disease

• Identifying tumors or abnormalities in the chest, abdomen, or spine

• Planning surgery or radiation therapy

• Detecting certain types of cancer

CT scans often require sedation or anesthesia so your pet can remain completely still, and are typically done at specialty hospitals.

MRI (Magnetic Resonance Imaging)

MRI uses a strong magnetic field instead of X-rays to create highly detailed images, especially of soft tissues like the brain, spinal cord, and nerves.

Best for:

• Diagnosing brain or spinal cord disorders

• Evaluating nerve damage or disc disease

• Investigating seizures, weakness, or behavior changes

MRI provides the clearest images of the nervous system but also requires general anesthesia and is usually performed at referral or specialty centers.

Which Imaging Tool Does My Pet Need?

Your specialist will recommend the best imaging method based on your pet’s symptoms and which part of the body needs evaluation. In many cases, multiple tools may be used together for a complete diagnosis.

We understand that diagnostic testing can feel stressful, but imaging plays a vital role in helping us give your pet the most accurate diagnosis—and the best care possible.

If you have questions about your pet’s recommended imaging or what to expect, we’re always here to help.