Ultrasonography

Ultrasonography for Dogs, Cats, and Other Pets

Veterinary Diagnostic Services at Southern Ocean Animal Hospital

TL;DR: Quick Summary

Ultrasonography, often called an ultrasound, is a safe imaging test that allows veterinarians to see inside your pet’s body in real time.

Unlike X-rays, ultrasound does not use radiation. It uses sound waves to create moving images of soft tissues and organs.

Veterinarians may recommend an ultrasound to evaluate:

The liver, kidneys, spleen, pancreas, intestines, bladder, and reproductive organs
Pregnancy and fetal heartbeats
Abdominal pain, vomiting, diarrhea, or unexplained weight loss
Fluid buildup in the chest or abdomen
Masses, tumors, cysts, or abnormal organ changes
The heart, when performed as an echocardiogram
Internal organs before collecting a guided sample or biopsy

At Southern Ocean Animal Hospital, Dr. Dan and the team use ultrasonography as part of a complete diagnostic plan to help find answers quickly, gently, and accurately.

ELI5: Ultrasonography Explained Simply

Think of ultrasound like a safe “inside camera” that uses sound instead of light.

A small handheld tool is placed on your pet’s skin with a little gel. That tool sends sound waves into the body. The sound waves bounce back and create a picture on a screen.

It helps your veterinarian see things like:

Is the liver normal?
Are the kidneys healthy?
Is there a bladder stone?
Is there fluid where it should not be?
Is a pregnancy developing normally?
Is the heart pumping the way it should?

Your pet does not feel the sound waves. Most pets only feel the cool gel and gentle pressure from the probe.

Introduction

When a pet is sick, the signs are not always obvious. A dog may vomit once and seem fine the next morning. A cat may quietly lose weight over several months. A rabbit may stop eating. A senior pet may seem tired, but the cause may be hidden inside the body.

That is where ultrasonography becomes such a valuable diagnostic tool.

Ultrasonography is a non-invasive imaging technique that uses high-frequency sound waves to create real-time images of the inside of the body. It is especially helpful for looking at soft tissues and organs that may not show enough detail on regular X-rays.

At Southern Ocean Animal Hospital, ultrasonography is used to help diagnose and monitor a wide range of conditions in dogs, cats, and other pets. It can help Dr. Dan evaluate internal organs, identify abnormal changes, guide treatment decisions, and determine when additional testing is needed.

Ultrasound is often used together with other diagnostic tools, including:

Physical exams
Bloodwork
Urinalysis
Digital radiology
Cytology
Endoscopy
Blood pressure monitoring
Echocardiography

The goal is simple: get the clearest picture possible of what is happening inside your pet, so the right treatment plan can begin.

Key Ideas for Pet Owners

Ultrasound is safe, painless, and non-invasive.
It uses sound waves, not radiation.
It is excellent for evaluating soft tissues and internal organs.
It can show movement in real time, such as heartbeats, blood flow, or intestinal motion.
It can help detect tumors, cysts, inflammation, fluid, pregnancy, bladder stones, and organ changes.
Some pets may need light sedation if they are anxious, painful, or unable to stay still.
Ultrasound often gives answers that cannot be found from a physical exam alone.
It may help avoid more invasive exploratory surgery in some cases.
It is commonly used in dogs, cats, rabbits, ferrets, and some exotic pets.

What Is Ultrasonography?

Ultrasonography is a diagnostic imaging method that uses sound waves to create pictures of internal body structures.

The veterinarian or trained imaging professional uses a handheld device called a transducer or probe. The probe is moved gently over the skin. A water-based gel helps the sound waves travel between the probe and your pet’s body.

The ultrasound machine then turns those sound waves into images on a screen.

Unlike a still photo, an ultrasound creates live images. This means Dr. Dan can often watch organs move in real time. For example, ultrasound can show:

The heart beating
The bladder filling
The intestines moving
Fluid moving inside the abdomen
Blood flow through certain vessels
Fetal heartbeats during pregnancy

That real-time view is one of the biggest advantages of ultrasound.

What Makes Ultrasound Different from X-Rays?

X-rays and ultrasound are both important, but they do different jobs.

X-rays are excellent for bones, chest structure, some bladder stones, swallowed objects, and general body outlines.

Ultrasound is better for soft tissues and organs.

Diagnostic Tool	Best For	Common Uses
Digital X-rays	Bones, lungs, chest, abdomen outlines	Fractures, arthritis, foreign objects, lung disease
Ultrasound	Soft tissues and organs	Liver, kidneys, spleen, bladder, pancreas, intestines, pregnancy
Echocardiography	Heart ultrasound	Heart murmurs, valve disease, heart function
Endoscopy	Inner lining of GI tract or airways	Biopsies, foreign body removal, direct visualization

Sometimes X-rays and ultrasound are used together. For example, if a dog is vomiting, X-rays may help identify a possible blockage, while ultrasound may help evaluate the intestines, pancreas, lymph nodes, and surrounding organs in more detail.

What Conditions Can Ultrasound Help Diagnose?

Ultrasound can help evaluate many medical problems.

Abdominal Pain

Pets with abdominal pain may have problems involving the stomach, intestines, liver, gallbladder, pancreas, spleen, kidneys, bladder, or reproductive organs.

Ultrasound can help identify:

Inflammation
Fluid buildup
Masses
Enlarged organs
Thickened intestinal walls
Gallbladder disease
Pancreatitis
Urinary problems

Vomiting and Diarrhea

Occasional stomach upset can happen, but repeated vomiting or diarrhea may point to something more serious.

Ultrasound may help evaluate:

Intestinal inflammation
Foreign material
Pancreatitis
Enlarged lymph nodes
Masses
Thickened bowel walls
Liver or gallbladder abnormalities

Unexplained Weight Loss

Weight loss can happen for many reasons, especially in older pets.

Ultrasound may help look for:

Organ changes
Cancer
Chronic inflammation
Kidney disease
Liver disease
Intestinal disease
Enlarged lymph nodes

Urinary Problems

Ultrasound is often used to evaluate the urinary system.

It can help examine:

Kidneys
Bladder
Ureters
Prostate in male dogs
Bladder wall thickness
Stones
Masses
Fluid buildup

Pets with urinary problems may show signs such as frequent urination, blood in the urine, straining, accidents in the house, or crying when trying to urinate.

A male cat that cannot urinate is an emergency.

Pregnancy Monitoring

Ultrasound is a safe way to confirm pregnancy and monitor fetal development.

It can help:

Confirm pregnancy
Detect fetal heartbeats
Assess fetal movement
Check for complications
Estimate pregnancy viability

Ultrasound is useful for confirming pregnancy, but it is not always the best tool for counting the exact number of puppies or kittens. X-rays later in pregnancy may be more accurate for estimating litter size because fetal skeletons are visible.

Fluid Buildup

Ultrasound is very helpful for finding abnormal fluid in the body.

Fluid may collect in:

The abdomen
The chest
Around organs
Around the heart

Fluid buildup may be caused by heart disease, trauma, cancer, liver disease, infection, bleeding, or other serious illness.

If fluid is present, ultrasound may help guide safe sample collection so the fluid can be tested.

Tumors, Cysts, and Masses

Ultrasound can help identify abnormal growths or changes in organs.

It may show:

Masses
Cysts
Nodules
Enlarged lymph nodes
Irregular organ texture
Fluid-filled structures

Ultrasound cannot always tell whether a mass is benign or cancerous by appearance alone. In many cases, a sample may be needed for cytology or biopsy.

Guided Sampling and Biopsy

One major benefit of ultrasound is that it can guide a needle to a specific area.

This may be used for:

Fine-needle aspiration
Fluid sampling
Tissue biopsy
Cyst drainage
Organ sampling

Because the veterinarian can see the target area in real time, ultrasound guidance can make sampling more precise and may help avoid unnecessary exploratory surgery in some cases.

Common Symptoms That May Lead to an Ultrasound

Your veterinarian may recommend an ultrasound if your pet has:

Vomiting
Diarrhea
Weight loss
Loss of appetite
Abdominal pain
Bloated abdomen
Increased thirst or urination
Blood in the urine
Straining to urinate
Difficulty breathing
Pale gums
Collapse or weakness
Abnormal bloodwork
Suspected pregnancy
Suspected cancer
Chronic illness that is not improving

Because pets cannot tell us exactly what hurts, ultrasound gives the veterinary team a deeper look.

Timeline of Symptoms: When to Call the Veterinarian

Symptom	Possible Concern	When to Call
Vomiting once but acting normal	Mild stomach upset possible	Monitor, call if it repeats
Repeated vomiting	GI disease, obstruction, pancreatitis	Same day
Not eating for 24 hours	Illness, pain, nausea	Same day, especially cats
Weight loss over weeks	Chronic disease, cancer, GI disease	Schedule promptly
Straining to urinate	UTI, stones, obstruction	Same day; emergency for male cats
Swollen abdomen	Fluid, mass, organ enlargement	Same day
Sudden weakness or collapse	Internal bleeding, heart issue, emergency	Emergency
Chronic diarrhea	Intestinal disease, inflammation	Schedule exam
Abnormal bloodwork	Organ disease possible	Follow vet recommendation

How the Ultrasound Procedure Works

Most ultrasound exams are straightforward and well-tolerated.

Step 1: Physical Exam and History

Dr. Dan starts by reviewing your pet’s symptoms, medical history, appetite, bathroom habits, medications, and recent changes at home.

This matters because ultrasound findings are most useful when they are interpreted alongside the full clinical picture.

Step 2: Preparing the Area

For most ultrasound exams, a small area of fur may need to be clipped. This helps the probe make better contact with the skin.

Gel is applied to the skin. The gel may feel cool, but it is harmless and wipes off afterward.

Step 3: Imaging

The probe is moved gently over the area being examined. Dr. Dan watches the images on the screen and evaluates the organs or structures.

Depending on the case, the ultrasound may focus on:

Abdomen
Chest
Bladder
Pregnancy
Heart
A specific lump or mass
A guided sample site

Step 4: Additional Sampling if Needed

If a mass, abnormal fluid, or suspicious change in an organ is found, Dr. Dan may recommend collecting a sample.

This may include:

Fluid analysis
Cytology
Culture
Biopsy

Step 5: Diagnosis and Treatment Plan

After reviewing the ultrasound findings, Dr. Dan explains what was seen and what it means.

The next step may include:

Medication
Diet changes
Surgery
Endoscopy
Referral to a specialist
Monitoring
Repeat ultrasound
Additional lab testing

Does My Pet Need Sedation?

Many pets can have an ultrasound without sedation.

Sedation may be recommended if your pet is:

Very nervous
Painful
Wiggly
Aggressive from fear
Having trouble staying still
Needing a guided sample or biopsy

Sedation is not a punishment or a sign that your pet is “bad.” It is often the kindest and safest way to reduce stress and get accurate images.

Is Ultrasound Safe?

Yes. Ultrasound is considered very safe when performed appropriately.

It does not use ionizing radiation. It is painless. Most pets tolerate it well.

The main mild inconveniences are:

Fur clipping
Cool gel
Gentle pressure from the probe
Possible sedation in some cases

If a biopsy or sample is collected, Dr. Dan will explain any additional risks based on your pet’s condition.

Ultrasonography in Dogs

Dogs commonly receive ultrasound exams for digestive, urinary, reproductive, liver, spleen, pancreatic, and cancer-related concerns.

Common Reasons Dogs Need Ultrasound

Vomiting or diarrhea
Suspected pancreatitis
Abdominal pain
Liver enzyme changes
Enlarged spleen
Bladder stones
Prostate disease
Pregnancy
Weight loss
Suspected tumors
Fluid in the abdomen
Abnormal bloodwork

Dog Breeds More Likely to Need Ultrasound

Any dog can need ultrasound, but some breeds are more likely to develop conditions where ultrasound is commonly used.

Labrador Retrievers

Labradors are known for eating things they should not. Ultrasound may be used when vomiting, abdominal pain, or a suspected blockage occurs.

Golden Retrievers

Golden Retrievers may need ultrasound to evaluate abdominal masses, spleen changes, liver abnormalities, or unexplained illness, especially as they age.

Miniature Schnauzers

Miniature Schnauzers are more commonly associated with pancreatitis and lipid-related issues. Ultrasound may be used when signs point to pancreatic inflammation.

Yorkshire Terriers

Yorkshire Terriers may be evaluated for digestive issues, liver concerns, or pancreatitis-like symptoms.

Cocker Spaniels

Cocker Spaniels may need ultrasound for liver, gallbladder, pancreatitis, or abdominal concerns.

German Shepherds

German Shepherds may need ultrasound for digestive problems, abdominal illness, or internal organ evaluation.

Boxers

Boxers may need imaging when cancer, abdominal disease, or une