What Is an Ultrasound?

An ultrasound scan is a medical test that uses high-frequency sound waves to create live images from the inside the body. Also called a sonogram or sonography, ultrasounds let doctors see the body’s soft tissues, which X-rays can’t do.

Doctors order ultrasounds for many reasons, such as to look for the causes of pain, swelling, and infection. Ultrasound scans are safe and painless.

What Is a Bladder Ultrasound?

A bladder ultrasound uses sound waves to make images of the bladder before and after urination (peeing).

An ultrasound machine sends sound waves into the bladder area and images are recorded on a computer. The black-and-white images show the internal structure of the bladder, as well as how much pee is in it.

Why Are Bladder Ultrasounds Done?

Doctors order bladder ultrasounds when there's a concern about bladder problems, such as trouble with peeing or daytime wetting.

A bladder ultrasound can show how much urine the bladder holds when it's full and whether someone completely empties the bladder when peeing. It can show if there’s anything unusual about the bladder, such as its size, the thickness of the bladder walls, and if there are blockages or kidney stones. A bladder ultrasound is often done along with a kidney ultrasound.

The doctor may ask that your child drink lots of fluids before the exam so that their bladder is full. The first image is done while your child’s bladder is full. Then, your child will be asked to pee before more images are recorded.

What if I Have Questions?

If you have questions about the bladder ultrasound or what the test results mean, talk to your doctor.