An ultrasound scan is a picture of part of the inside of the body. It uses sound waves of a frequency above the audible range of the human ear.
What is an ultrasound scan?
A small hand-held sensor pressed carefully against the skin surface generates sound waves and detects any echoes reflected back off the surfaces and tissue boundaries of internal organs. The sensor can be moved over the skin to view the organ from different angles. The images are displayed on a screen and recorded for subsequent study.
Ultrasound images complement other forms of scans and are widely used for many different parts of the body. They can also be used to study blood flow and to detect any narrowing or blockage of blood vessels, for example, in the neck.
Ultrasound is also used for intimate examinations; for example, of the prostate gland in men or the womb or ovaries in women. For some of these examinations, it may be necessary to place an ultrasound probe in the vagina or the rectum to look at internal structures. If you are having an intimate examination the sonographer will describe the procedure to you, and your consent will be required.
Who will be doing the ultrasound?
Sonographers (radiographers) or radiologists (doctors) who have specialized training in the technique of ultrasound.
They carry out a great number of these examinations and will provide a descriptive report of their findings to your doctor.
Where will the procedure take place?
Generally in the radiology department.
Do I need to make any special preparations in advance?
Some preparation may be required. If your pelvis, kidney or bladder are to be scanned, you may be required to ensure that your bladder is full before the examination can begin. For some examinations such as the gall bladder and pancreas, you may be required to fast for a specified number of hours. If so, this will be explained in the accompanying appointment letter. You should tell the radiology department in advance if you have had a similar ultrasound recently.
If you are diabetic please bring some food and your medication with you on the day of the scan.
Can I bring a relative/friend?
Yes. However, it may not be suitable for a friend to remain in the scanning room if you undergo an intimate examination.
When you arrive
Please report to the reception desk in the radiology department.
The sonographer will explain the procedure for your examination and, if you have to undress for the procedure, may show you to a private cubicle where you will undress.
Who will I see?
You will be seen by a radiologist or a sonographer depending upon the type of investigation you are having.
What happens during the scan?
You will be taken into a room where you will be asked to lie down on a couch, the room may be dimmed so that the images on the screen can be seen more clearly. A gel will be applied to your skin over the area to be scanned, for example, the abdomen. The gel allows the sensor to slide easily over the skin and helps to produce clearer images.
You may be asked to take deep breaths and to hold your breath for a few moments. For a scan of the bladder, the bladder may occasionally not be full enough for the examination and you may be asked to drink more fluid.
The radiologist/sonographer will slowly move the sensor over your skin while viewing the images on the screen. Records of selected images will be made so that they can be viewed later. Upon completion, the gel will be wiped off and you will be free to get dressed.
Will it be uncomfortable?
Ultrasound itself does not produce discomfort and apart from the sensor on your skin you will not feel anything. If a full bladder is required there may be some associated discomfort. If pressure has to be applied to the skin surface over an inflamed organ, e.g. the gallbladder, to check what is causing the pain, this may increase the amount of pain coming from that organ temporarily.
How long will it take?
The process of carrying out a scan usually takes about 20-30 minutes. Your total time in the department is likely to be about 30–40 minutes.
Are there any risks?
No, there are no known risks and it is considered to be very safe.
Can I eat and drink afterwards?
When will I get the results?
The scan will be examined after your visit and a written report on the findings sent to your referring doctor.
We hope your questions have been answered by this leaflet, but remember that this is only a starting point for discussion about your examination.
Make sure you are satisfied that you have received enough information about the procedure, before you consent to the examination.
Other sources of Information
For general information about radiology departments, visit the Royal College of Radiologists
For health advice or information you can call NHS Direct on 0845 45647 or visit the
The leaflet tells you about having an ultrasound.