Above is an ultrasound image of a baby. Note the baby is sucking its thumb. 

In this view,  you can see the mouth and nose on the baby's face. You can also see the baby's spine, which appears white in this image.

Sonogram of a normal testicle.

Above two images: sonograms of a normal gall bladder. 

Ultrasound uses sound echoes to visualize internal structures and tissues. Perhaps the most widely recognized use of ultrasound is as a diagnostic tool used to examine the fetus during pregnancy. By using ultrasound, the fetus can be imaged without being exposed to ionizing radiation. Measurements can be taken that determine the age and health of the unborn baby.

Ultrasound can reveal information about the shape, size, composition, and texture of tumors and cysts that could otherwise not be visualized, such as some types of gallstones and kidney stones.  For women, ultrasound is particularly important in visualizing abnormalities of the ovaries, fallopian tubes, or uterus. Other uses of ultrasound include imaging of an infant's brain and spinal cord, thyroid gland, prostate gland, and scrotum and testicles.

The uses of ultrasound continue to grow. For example, doppler ultrasound, which visualizes blood flowing through vessels is being used to study abdominal structures such as the liver, kidneys and abdominal aorta, and superficial structures such as the testicles. 3-D ultrasound is a relatively new type of ultrasound that is now available. It can be used in selected cases to visualize fetal anatomy or to evaluate abnormal masses.

Preparing for an Ultrasound

There is no special preparation necessary to receive an ultrasound. Your doctor or radiologist will discuss any special instructions with you.

What to Expect During an Ultrasound

Typically, during an ultrasound, you will lie on a table and a device that produces sound waves and then receives their echoes is placed on your skin over the area that is to be visualized. There is no discomfort. Images are displayed on a video screen and can be recorded for further study.

For more information about what to expect during ultrasound examinations on specific areas of the body, select from the list below.

Obstetrical Ultrasound
Abdominal Ultrasound
Pelvic Ultrasound
Prostate Ultrasound

Obstetrical Ultrasound

The most common reasons for having an obstetrical ultrasound is to help your doctor determine the age and growth of your baby. Other reasons for the test may include determining the position of the baby or the placenta and determining the number of fetuses you may be carrying. The ultrasound may also be used to check the amount of fluid surrounding the baby, detect certain birth defects, and as a comparison to results from other tests. You may have more than one ultrasound during your pregnancy.

To prepare for the test, you will be asked to drink 4-6 large glasses of water one hour before the test. Having the bladder full helps push the bowel to the side so the uterus can be more easily seen.

Gel is placed on your abdomen and a transducer is placed on your skin. The transducer is moved to different positions to see the baby. In very early pregnancy, it may be necessary to use a special transducer in the vagina to see the baby better.

Abdominal Ultrasound

An abdominal ultrasound may be needed to find the cause of pain, to detect gallstones, to look for blockage of kidneys, and for observing enlargements (aneurysms) in the abdominal aorta.

Major organs including the liver, gallbladder, pancreas, spleen, and kidneys and large blood vessels can be seen with ultrasound. Ultrasound can not image through bones, several layers of tissue, or bowel gas. The test images may be less clear for obese patients and patients with a lot of bowel gas.

Although there is usually no preparation for this test, if your pancreas, gallbladder, or aorta will be viewed, you need to have nothing to eat or drink for eight hours before the test. You should also avoid gas-producing foods, such as cabbage and beans, and carbonated beverages before the test.

Gel will be placed on your abdomen and a transducer placed on your skin. The transducer will be moved to different positions to see your organs and blood vessels.

The examination usually takes between 15 and 30 minutes. The test will be done by a sonographer especially trained to complete this test, and a radiologist will read the test and report the results to your doctor.

Pelvic Ultrasound

A pelvic ultrasound may be needed when a manual gynecological exam does not provide all the information your doctor needs. Commonly, this test is used to find the cause of pain or bleeding.

There are two methods for performing pelvic ultrasound: abdominal and vaginal. Depending on the reason for the test, either one or both of these methods may be used. To prepare for the test, you will be asked to drink about 4-6 large glasses of water one hour before the test. Having a full bladder helps push the bowel to the side so the pelvic organs can be more easily seen.

With the abdominal ultrasound, gel will be placed on your abdomen and a transducer placed on your skin. The transducer will be moved to different positions to obtain the best pictures.

During a vaginal ultrasound, a special transducer is placed in the vagina. You will be asked to empty your bladder before the test. A cover is placed over the tip of the transducer and gel is applied. The tip of the transducer is smaller than the standard speculum used when your doctor performs a routine pap smear. Inserting the transducer is like using a tampon and is usually not painful. You will need to be in the same position as when your doctor performs a pap smear.

The ultrasound will take about one hour. The test will be done by a sonographer especially trained to complete this test, and a radiologist will read the test and report the results to your doctor.

Prostate Ultrasound

Prostate ultrasound is used with physical examination to identify and localize diseases. Some diseases involving the prostate gland include infection, enlargement, and cancer.

The prostate gland is located in front of the rectum. By placing the special transducer in the rectum, the sound waves only have to travel a short distance. Gel is placed on the covered transducer, and the transducer is placed in the rectum. The test will feel about the same as a rectal exam performed by your doctor. Sometimes an enema may be given before the test.

The ultrasound usually takes less than 20 minutes. The test will be done by a sonographer specially trained to complete this test, and a radiologist will read the test and report the results to your doctor.

You may have some mucous discharge or minimal spotting of blood from your rectum following the test, especially if you have hemorrhoids. However, you will be able to do all of your usual activities.