Diagnostic imaging lets us see what a physical exam alone can't, giving us a clear, non-invasive look at your dog's bones, organs, and soft tissues. Digital X-rays show bones, joints, and larger structures clearly, while ultrasound gives a detailed, real-time view of soft tissues, organs, and body cavities. Together, they help us catch problems early and figure out exactly what's going on before deciding on treatment.

Imaging is valuable well beyond a single diagnosis. It helps us monitor chronic conditions over time, check how well a treatment is working, and in emergencies, get a fast, accurate read on what's happening so we can act quickly. It's one of the more powerful tools we have for understanding your dog's health beyond what we can see or feel during an exam.

What Types of Diagnostic Imaging Do We Offer?

• •Digital X-rays (radiography) — usually the first step for evaluating bones, joints, the chest, and abdomen. Digital X-ray uses less radiation than older film-based systems and lets us view images immediately.
• •Ultrasound — better suited than X-ray for evaluating soft tissue and organs in detail. Real-time, painless, and commonly used to examine the abdomen, and through our echocardiogram services, the heart.
• •CT (computed tomography) — offered in-house through our mobile CT unit, available at all three of our locations. CT is reserved for cases needing more detail than X-ray or ultrasound can provide, such as evaluating deep tumors, complex fractures, or the chest and abdomen in greater detail. Unlike in human medicine, dogs must be placed under general anesthesia for a CT scan, since they can't be asked to hold still on command, and even small movements can blur the images. Anesthesia lets us capture the clearest, most diagnostic scan possible.

General overview of imaging modalities via the Merck Veterinary Manual.

Ultrasound vs. X-Ray vs. CT: What's the Difference?

Each type of imaging shows us something different, and we often use more than one together to get the full picture.

• •X-ray (radiograph) is best for bones and larger structures. It's a quick, still, two-dimensional image, ideal for spotting fractures, joint problems, or something your dog swallowed. It's usually our first step because it's fast and needs little to no sedation.

• •Ultrasound is best for soft tissue. It uses sound waves instead of radiation to create a real-time, moving image, so it's better than X-ray for looking closely at organs like the liver, kidneys, bladder, and heart, and for detecting fluid or masses that an X-ray might miss.

• •CT (computed tomography) is the most detailed option. It takes hundreds of cross-sectional X-ray images and combines them into a detailed, 3D picture, useful when we need a level of detail that X-ray and ultrasound can't provide, such as complex fractures, tumors, or planning for surgery. Because it requires the dog to be completely motionless for an extended scan, it's the one option of the three that always requires general anesthesia.

When Do We Recommend Each Type of Imaging?

The symptoms or concerns your dog is showing usually point us toward the right imaging from the start.

We may recommend an X-ray for:

• •Limping or lameness, or a suspected broken bone
• •Swallowing a foreign object (like a toy, sock, or bone)
• •Chronic coughing or difficulty breathing
• •Straining to urinate or suspected bladder stones
• •Confirming pregnancy and estimating litter size later in gestation
• •General screening for unexplained pain or injury after a fall or accident

We may recommend an ultrasound for:

• •Vomiting or diarrhea that doesn't resolve on its own
• •Abdominal pain or a swollen, tender belly
• •A new heart murmur or suspected heart disease- this would be considered an Echocardiogram
• •Unexplained weight loss or lethargy
• •Monitoring liver or kidney disease over time
• •A mass or lump found on exam that needs a closer look

We may recommend a CT scan for:

• •Complex or multiple fractures that need detailed surgical planning
• •Cancer staging or evaluating a tumor before treatment
• •Chronic nasal discharge or sneezing that hasn't responded to treatment
• •Neurological symptoms, like seizures, wobbliness, or a head tilt
• •Cases where X-ray or ultrasound findings are unclear and more detail is needed before treatment

What Can Diagnostic Imaging Detect?

• •Fractures, dislocations, and joint abnormalities
• •Organ enlargement or abnormal shape
  • Congenital Liver shunts

    • A liver shunt, medically known as a portosystemic shunt, is a birth defect a dog is born with. Normally, blood from the intestines flows through the liver first, where toxins and waste products get filtered out before that blood reaches the rest of the body. With a liver shunt, an abnormal blood vessel allows blood to bypass the liver entirely, so those toxins circulate through the body unfiltered. This can affect growth, brain function, and overall development, and it's most often diagnosed in puppies or young dogs who aren't growing or thriving as expected.

      Liver shunts fall into two main types, and imaging is what tells us which one we're dealing with:

      • Extrahepatic shunts the abnormal vessel sits outside the liver. This is the more common type, and it tends to show up in small breeds, including Yorkshire Terriers, Miniature Schnauzers, Maltese, Shih Tzus, Dachshunds, and Poodles.
      • Intrahepatic shunts the abnormal vessel sits inside the liver itself. This type is seen more often in larger breeds, such as Irish Wolfhounds, Golden Retrievers, Labrador Retrievers, Old English Sheepdogs, and Australian Shepherds.
• •Gastrointestinal obstructions, including swallowed foreign objects
  • Imaging also tells us exactly where an obstruction is sitting, whether that's the stomach, the duodenum (the first section of small intestine just past the stomach), further down in the jejunum or ileum (the rest of the small intestine), or the colon, which matters a great deal for surgical planning, since the approach, risk, and recovery can look very different depending on the exact location
• •Fluid accumulation in the chest or abdomen
• •Heart size and function, and other cardiac concerns
  • Myxomatous Mitral Valve Disease (MMVD) Where the mitral valve in the heart gradually thickens and degenerates, so it no longer closes properly and starts to leak. This is by far the most common heart disease in small-breed dogs, and King Charles Cavaliers are especially predisposed, with studies showing the vast majority develop it by age 10. We listen closely for a heart murmur in this breed and may recommend more frequent cardiac imaging as they age.
  • Dilated Cardiomyopathy (DCM) ​​Where the heart muscle itself weakens and the chambers stretch and enlarge, making the heart a less effective pump. Great Danes, along with Boxers, Doberman Pinschers, and other large and giant breeds, are known to be predisposed. Imaging can catch the early enlargement before a dog shows outward symptoms like weakness or exercise intolerance.
  • Hypertrophic Cardiomyopathy (HCM) This is where the walls of the heart thicken, making it harder for the heart to fill and pump normally. HCM is the most common heart disease in cats, and it's frequently silent in its early stages, which is part of why we recommend an echocardiogram (ultrasound of the heart) for cats showing any suspicious signs, or as a screening tool in predisposed breeds like Maine Coons and Ragdolls.

• •Tumors and masses

Why We Recommend Yearly Diagnostic Imaging

Most serious conditions don't announce themselves. A dog can be quietly developing heart disease, an early tumor, or organ changes for months before any outward symptoms show up, by which point the disease has often had time to progress. Diagnostic imaging lets us look past what we can see or feel during a physical exam and catch these changes while they're still small, often long before your dog seems sick at all.

This is why we recommend yearly diagnostic imaging as part of routine care, not just something we reach for once your dog is already showing signs of a problem. We especially recommend it for dogs over the age of six, senior dogs, and any dog with a prior medical history, as a standard part of their annual wellness visit.

The earlier we identify a problem, the more options we typically have to treat it, and the better those treatments tend to work. Catching something small and early is almost always easier on your dog, and easier on your wallet, than catching it once it's already advanced. That's the real value of making imaging a routine part of your dog's care rather than something we only use when something already seems wrong.

Will My Dog Need Sedation?

Most X-rays and ultrasounds are done on an awake dog. If your dog is calm and can hold still comfortably, no sedation is needed. Sedation may be recommended if your dog is anxious, in pain, or squirming too much to get a clear image, or for certain X-rays (like the spine, skull, or teeth) that require the muscles fully relaxed to get an accurate picture. CT is different: because your dog must remain completely still for an extended scan, and unlike a human patient, can't be asked to hold still on command, CT always requires full general anesthesia to get a clear, diagnostic image. When CT is needed, we put together a Pre-Anesthetic Plan to screen for risk factors beforehand.

What to Expect From Your Dog's Imaging Appointment

Our Orange County Locations

The Animal Doctors of Orange County offers dog diagnostic imaging, including X-ray, ultrasound, and in-house CT via our mobile CT unit, at our Anaheim, Buena Park, and Mission Viejo locations, serving families throughout Fullerton, Cypress, La Palma, Garden Grove, Orange, Laguna Hills, Lake Forest, and Aliso Viejo. If something seems off with your dog, imaging is often the fastest way to get real answers. 

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Related Services: Dog Lab Tests | Pre-Anesthetic Plan | Dog Surgery | Dog Cancer | Emergency Medicine