Urologists use ultrasounds to see how the bladder is draining during urination. Ultrasounds can also detect other causes of overactive bladder.

Overactive bladder (OAB) is not a disease but a group of symptoms that cause a sudden, urgent need to urinate. As many as 30–40% of adults may have symptoms of OAB at any time.

A doctor may recommend an ultrasound for a person with OAB. In addition to ruling out other underlying causes of a person’s symptoms, this imaging test can check the health of the urinary tract.

This article explains what a bladder ultrasound is, how it works, and what to expect from the procedure.

The bladder is an organ made of smooth muscle that stores urine. The kidneys produce urine as a waste product. A healthy bladder can hold the urine until a person goes to the bathroom.

OAB causes the sudden, uncontrollable urge to urinate. Other symptoms include:

  • incontinence when the urge to urinate occurs
  • frequent trips to urinate
  • waking more than once in the middle of the night to urinate

These symptoms can negatively affect a person’s quality of life.

Up to 58% of people with OAB have symptoms due to overactive muscles in the bladder. Overactive muscles cause the bladder to contract more frequently.

Other possible causes of OAB include:

  • a disruption in nerve signals between the bladder and the brain
  • hormonal changes
  • urinary tract infections
  • neurological disorders
  • conditions that affect the spinal cord and brain
  • certain medications
  • abnormalities in the urinary tract, such as bladder stones

To diagnose a person with OAB, a doctor may do a physical exam right away or refer a person to a specialist. The doctor will often ask the person to keep a log of their urination habits. The doctor will also likely order other tests, including urine tests and a bladder ultrasound.

A bladder ultrasound is a test that uses sound waves to produce images of the bladder. The test is not painful. However, a person may need to hold their urine so that the bladder is full for part of the scan, and this may be uncomfortable.

The American Urological Association notes that healthcare professionals primarily use bladder ultrasounds to see how the bladder is draining during urination. They measure the urine that remains in the bladder immediately after a person urinates. If urine remains, this can indicate an underlying problem, such as bladder dysfunction.

A bladder ultrasound can also provide information on the bladder wall and the pouches of the bladder, called the diverticula. In addition, it can reveal any stones or sizeable tumors in the bladder. In people with a prostate, the test will show the size of this gland.

Some types of ultrasounds will check the blood flow to and from the bladder.

A person will not generally need to do much to prepare for a bladder ultrasound other than drinking several glasses of water about 2 hours before the test. This gives the bladder a chance to fill.

During a transabdominal ultrasound, a person will lie on their back on an exam table. A healthcare professional will then put a clear, water-based gel on the area of the person’s skin over the lower abdomen or pelvis. They will use a handheld device called a transducer to scan the area.

The healthcare professional will take some images and measurements while the person’s bladder is full. Afterward, they will usually ask the person to use the bathroom and empty their bladder. The healthcare professional may then take more measurements and images.

As soon as the ultrasound is complete, a person can go back to their regular routine and tasks.

Doctors may use a transvaginal ultrasound to look at the thickness of the bladder walls in people with a vagina.

A person can expect to discuss the results of the ultrasound with their doctor soon after the procedure. The doctor will go over any findings.

Ultrasound imaging can detect bladder muscle overactivity by measuring the thickness of the bladder wall. Researchers have determined that a thicker bladder wall may be associated with OAB.

Ultrasound imaging can also detect other underlying conditions that are responsible for OAB, such as bladder stones. Knowing the cause of a person’s symptoms allows a doctor to treat them more effectively.

Overactive bladder describes a variety of related conditions that cause a person to experience symptoms such as a frequent urgent need to urinate and urine leakage. A person who experiences these symptoms should talk with their doctor.

A doctor may use an ultrasound to help diagnose OAB. The procedure is minimally invasive, and a person can carry on with their usual daily tasks afterward. If the results indicate that a person has OAB, a doctor can work with them to develop an effective treatment plan.