What is ultrasonography?

In ultrasonography, or ultrasound, high-frequency sound waves, inaudible to the human ear, are transmitted through body tissues. The echoes are recorded and transformed into video or photographic images.

Ultrasound images help in the diagnosis of a wide range of diseases and conditions. The idea for ultrasonography came from sonar technology, which makes use of sound waves to detect underwater objects.

Ultrasound is used to create images of soft tissue structures, such as the gall bladder, liver, heart, kidney, female reproductive organs-- and even of babies still in the womb. Ultrasound can also detect blockages in the blood vessels.

Ultrasound cannot be used to image bones because they are too dense to penetrate. In addition, the intestinal tract and normal lung tissue are not easily identified with ultrasound because air or gas can interfere with the production of ultrasound images.

Ultrasound may be used with other diagnostic procedures or by itself.

What is examined during a renal ultrasound?

The kidneys are examined during a renal ultrasound to determine their size, shape and exact position.

What is examined during a renal/pelvic ultrasound?

The kidneys are examined by ultrasound to determine their size, shape and exact position. The bladder may be evaluated to determine the cause of unexplained blood in the urine or difficulty in urinating, or to look for bladder stones.

Before the renal or pelvic ultrasound

Drink only clear liquids (tea, black coffee, strained juices and clear broth) from midnight the night before the test until your test is complete.

  • Finish drinking one quart (32 oz.) of fluids one hour before your scheduled test. Once you start drinking, do not empty your bladder until the exam is completed.
  • Failure to follow the above preparation will result in delays or possible cancellation of your examination.
On the day of the test

Please do not bring valuables such as jewelry and credit cards.

  • It is very important to arrive with a full bladder. This allows the technologists and radiologist to view the bladder while it is full and after it has been emptied.
  • Your ultrasound test is performed by registered, specially trained technologists and interpreted by a board-certified radiologist.
  • You may be asked to change into a hospital gown.
During the test

You will lie on a padded examining table. A warm, water-soluble gel is applied to the skin over the area to be examined. The gel does not harm your skin or stain your clothes. A probe is gently applied against the skin. You may be asked to hold your breath briefly several times.

There is virtually no discomfort during the test. Because a full bladder is required for the test, you may feel some discomfort when the probe is applied.

The ultrasound takes about 40 minutes to complete.

Are there any side effects?

Studies have shown ultrasound is not hazardous. There are no harmful side effects. In addition, ultrasound does not use radiation, as X-ray tests do.

After the test

The gel will be wiped off your skin. Your physician will discuss the test results with you when the results become available.

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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 4/2/2010...#4997