The testicles are the male reproductive organs that produce sperm and the hormone testosterone. They are located in the scrotum, the flesh-covered sac that hangs between the legs at the base of the penis.

Testicle ultrasound is an imaging procedure that examines the testicles and other parts inside the scrotum. The ultrasound machine sends out high-frequency sound waves, which reflect off areas in the scrotum to create a picture.

There is no ionizing radiation exposure with this test. Ionizing radiation procedures such as x-ray carry a small cancer risk and may damage sperm, but this test does not.

You will lie on your back with your legs spread. The health care provider will drape a cloth or apply wide strips of adhesive tape across your thighs under the scrotum. The scrotal sac will be slightly raised, with the testicles lying side by side.

A clear, water-based conducting gel is applied to the scrotal sac to help with the transmission of the sound waves. The ultrasound transducer (a handheld probe) is then moved over the scrotum.

No special preparation is necessary for this test.

Children:

The preparation you can provide for this test depends on your child's age, previous experiences, and level of trust. For specific information regarding how you can prepare your teen, see adolescent test or procedure preparation (12 to 18 years). This test is seldom performed on children younger than 12.

There is little discomfort. The conducting gel may feel slightly cold and wet.

The ultrasound is done to help determine why one or both testicles have become larger, or the reason for testicular pain.

The testicles and other areas in the scrotum are normal in appearance.

Abnormal results may indicate a benign cyst (an abnormal sac containing fluid), a testicular tumor (abnormal tissue growth that may or may not be cancerous), an area of infection with or without abscess formation, a testicular torsion (twisting), or another problem.

There are no documented risks. No exposure to ionizing radiation is involved.

In certain cases, Doppler ultrasound may be useful to identify blood flow within structures inside the scrotum. For example, Doppler ultrasound is very helpful in the assessment of testicular torsion -- blood flow to the twisted testicle may be reduced.