Ultrasound imaging, sometimes called sonography is a method of obtaining images from inside the human body by using high frequency sound waves. As sound passes through the body, echoes are produces that identify how far away an object is, the size of the object, its shape and consistency (solid, fluid or mixed). Ultrasound can also measure the flow of blood using a specialized method called Doppler ultrasound. No radiation is used with ultrasound imaging. Ultrasound is a useful way of examining many of the body’s internal organs such as the liver, gallbladder, spleen, pancreas, kidneys, bladder, uterus, ovaries, thyroid and testicles as well as Veins, arteries, and fetal anatomy.

Ultrasound has many benefits. It is noninvasive (does not use any needles or injections) and is usually painless. Ultrasound is easily available. It uses no ionizing radiation (x-ray), which makes it the preferred method to image pregnant women and their unborn children. Ultrasound can provide real-time imaging which makes it useful for guiding biopsy procedures.Ultrasound does not penetrate bone. For visualization of bone, other imaging modalities, such as MRI may be used. Ultrasound does not pass through air. Therefore, it is not useful in evaluating the organs that contain gas such as the stomach, small intestine or large intestine. Intestinal gas may also prevent visualization of deeper structures such as the pancreas and aorta. Patients suffering from obesity are more difficult to image because extra tissue weakens the sound waves as they pass deeper into the body.There are no known harmful effects on humans.

Frequently Asked Ultrasound Questions

When is ultrasound used?

Many expectant parents have first seen their unborn child with an ultrasound exam. Ultrasound is used extensively for evaluating pelvic and abdominal organs, blood vessels, and can help a physician determine the source of pain, swelling or infection in many parts of the body. Because ultrasound provides real-time images, it is also useful as a guide for needle biopsies. Ultrasound is also used to evaluate superficial structures such as the breast, thyroid and testicles.
Doppler ultrasound is a special technique used to examine blood flow. Doppler images can help to determine blockages of blood flow (such as a blood clot) and build up of plaque inside a blood vessel


How do I prepare of my ultrasound examination?

The exam preparation will vary slightly based on which part of the body you are having imaged. The different preparations are detailed below:

Abdomen, or aorta: If your exam is before noon, do not eat or drink anything after midnight the day before your exam. You may take your medications with a small amount of water. If your exam is after noon, you may eat a low fat breakfast before 8:00 a.m. (no milk, butter, cream, cheese, peanut butter), then do not eat or drink anything else prior to the exam. You may take your medications with a small amount of water.

Kidneys: drink 24 ounces of water from 90 to 60 minutes before your exam starts. Do not empty your bladder until after your examination. Without water in the bladder we can not evaluate your bladder at the time of the procedure.

Pelvis or obstetrical: drink 32 ounces of water from 90 to 60 minutes before your exam starts. Your bladder must be full for the exam. Do not empty your bladder until after the examination.

Scrotal, testicular, breast, and thyroid ultrasound: There is no prep for this procedure

Arteries or veins: no preparation needed.


Why do I need to fast for my abdominal ultrasound?

Ultrasound cannot penetrate bowel gas and bowel substance which  food and drink will cause.  Food and drink can also  affect how the gall bladder looks and reacts. Therefore, it is important that you not have anything to eat or drink (including water) for 8 hours prior to the procedure. If you are on medication that you cannot go without, you may take it with a very small amount of water.


Why do I need to fill my bladder for my pelvic and OB ultrasounds?

A full bladder pushes the intestines (which contain air) out of the way of the pelvic organs. A full bladder also pushes the fundus of your uterus away from your intestines in order to be viewable.  In cases of an OB ultrasound the filling of the bladder is important to evaluate the cervix.  Cervical evaluation in an OB ultrasound is essential part of the exam. This makes the ultrasound picture clearer.

Obstetrical Ultrasound

What are common uses of this procedure?

Obstetrical ultrasound is used to evaluate an embryo or fetus. This ultrasound can estimate the age of the pregnancy, diagnose congenital abnormalities, evaluate the fetal and placental location and determine if there are multiple pregnancies. Conventional ultrasound displays the images as thin sections (like looking at single slices of bread in a loaf.) Ultrasound can watch the heart beat and movement of the fetus like an ongoing movie.

What should I do to prepare for my OB ultrasound procedure?

You should wear a loose fitting two-piece outfit for the examination, which allows for easy access to the lower abdomen.

You will need to have a full bladder for this examination. You should drink 4-6 glasses of water before your exam. In order for the water to have time to get to your bladder, you should be finished drinking one hour prior to your exam time. Do not empty your bladder before your exam.


What can I expect during the procedure?

If you are less than 14 weeks along:
You will be asked to lie on your back on the exam table with your bladder full. The technologist will use gel and press a transducer against the pelvis. The transducer will be swept back and forth across the pelvis to image the areas of interest.
Most early OB ultrasounds require a transvaginal ultrasound. This is performed by inserting a probe into the vagina – similar to having a pelvic exam at your physician’s office.
Before the vaginal ultrasound, you will be asked to empty your bladder completely. You will also need to change into a gown. You will then be asked to lie on your back with your feet up in stirrups. The transvaginal probe is inserted into the vagina and images of the fetus, uterus and ovaries are obtained.
You may experience some discomfort while images are obtained with your bladder full. The transvaginal ultrasound should not be painful. It is usually more comfortable than a gynecological exam.
The entire exam should take approximately 30 minutes.

If you are more than 14 weeks pregnant:

You will be asked to lie on your back on the exam table with your bladder full. The technologist will use gel and press a transducer against the lower abdomen. The transducer will be swept back and for the across the pelvis to image the areas of interest. The technologist may have to push and angle the transducer in various positions to get accurate pictures of the fetus.

The exam should take approximately 45 minutes.

You will receive pictures of your baby to take home.