Indications for Ultrasound

Ultrasound is valuable in many circumstances. In some situations—during pregnancy, for example—ultrasongraphy is the safest available imaging test. Ultrasound also produces the best images of the developing fetus.

In gallbladder disease, ultrasound is standard as well. CT scan and ultrasound work together in other parts of the abdomen, but ultrasound is still standard in the female pelvis. From the patient's perspective, if you have ever had a contrast venogram, in which the contrast dye was injected into a vein in your foot, you will appreciate the value of the noninvasive ultrasound study that can make the same reliable diagnosis in a fraction of the time with no contrast and no needles.

Prostate biopsies are most often performed under ultrasound guidance. Ultrasound also can be used to examine the blood flowing through the carotid artery in the neck, which nourishes the brain, and as a first line test for appendicitis.

Ultrasound Procedure

What actually happens during an ultrasound depends on which type of test you are going to have. One of the most common studies is the abdominal ultrasound. To prepare for this test, the ultrasound technologist explains the test and asks you a number of questions. You will be asked to climb up on an examining table after you have removed whatever clothing is necessary.

Next, a water-soluble substance is applied to the area that is going to be imaged. If it hasn't been warmed up, it will feel cold.

The technologist will then scan by sliding the transducer over the areas of interest. Because there is so much gas on the left side of the abdomen, the technologist will usually focus on the right side where the liver offers a "window" into the abdomen. You may be asked to take deep breaths so that certain structures like the gallbladder come into view.

The radiologist will notify you about the results of the ultrasound. If you don't hear from the radiologist, contact your primary care physician to find out the results.

Whereas in the upper abdomen, the liver is the acoustic window; in the pelvis, it is the bladder. To perform a pelvic ultrasound, most radiology departments first do a study over the lower abdomen with a dilated urinary bladder, meaning you have to have a full bladder.

Women also may have a transvaginal exam, which is done by inserting a probe into the vagina and scanning the pelvic structures. These transvaginal studies are very well tolerated, except in the young and in the elderly, and they provide much more detailed information about the uterus and ovaries.

If you are going to have a Doppler study (an ultrasound that studies movement) for your carotid arteries or a Doppler study has been added to your abdomen and pelvis ultrasound, you will also probably hear the sound as well. The pitch of the sound tells the technologist a lot about the flow of blood in whatever structure is being imaged.

There are no significant risks or side effects to ultrasound.

Publication Review By: the Editorial Staff at

Published: 01 May 2000

Last Modified: 23 Mar 2015