Ultrasound Scan

An ultrasound scan uses high-frequency sound waves to create an image of part of the inside of the body.

How ultrasound scans work

A small device called an ultrasound probe is used, which gives off high-frequency sound waves. You cannot hear these sound waves, but when they bounce off different parts of the body, they create “echoes” that are picked up by the probe and turned into a moving image. This image is displayed on a monitor while the scan is carried out.

How long does it take?

This depends on the area we are scanning, but most scans take between 15 -30 minutes.

Do I need to prepare for a scan?

Before having some types of ultrasound scans, you may be asked to follow certain instructions to help improve the quality of the images produced. For example, you may be advised to:

• Drink water and not go to the toilet until after the scan. This may be needed before a scan of your pelvic area
• Avoid eating or drinking for several hours before the scan. This may be needed before a scan of your digestive system, including the liver and gallbladder.

Your appointment letter will tell you what preparation you need to follow.

Who will perform my scan?

The ultrasound examination will be performed either by a specialist doctor, called a radiologist, or a highly trained health care practitioner called a sonographer. There will also be an imaging assistant in the room.

Can anyone accompany me for the scan?

Your ultrasound scan is a medical examination. It is important that staff are able to concentrate and perform all aspects of the scan without distraction. Guests and children are not allowed. Only parents of children under 16 years of age and support workers are allowed in the scanning room.

What will happen during the scan?

You will be taken into the scanning room and asked to lie or sit on a couch next to the ultrasound machine. You may be asked to remove or adjust your clothing, so the area to be scanned is visible. The lights will be dimmed so the scan images can be seen clearly on the monitor. A lubricating gel is put on your skin to allow a small hand-held probe to be moved smoothly over the part of the body being examined.

Normally you should not feel anything other than the probe and gel on your skin, but sometimes, if you are experiencing pain or we have to apply pressure with the probe to obtain a good image, you may experience some discomfort. Any concerns can be discussed with the radiologist or sonographer performing the examination.

For patients having a scan of their pelvic organs (uterus and ovaries), an internal (transvaginal) scan may be helpful as it gives better quality images. This will be discussed with you in the scan room and will only be performed with your consent.

When will I get the results?

For some types of scan, the radiologist or sonographer who is carrying out the examination will be able to discuss the ultrasound findings with you after the scan has taken place. In other cases the images will need to be analysed further before a final report is issued. A full report of the examination will be sent to your referring doctor.

Please contact your GP surgery if a follow-up appointment has not been scheduled.

If you have been referred by a hospital consultant, a follow-up plan will be made and you will be contacted in two to four weeks. If no follow-up plan is arranged in this time scale, please contact your consultant’s secretary.

Contact numbers

We hope that you have found this information useful. If you have any questions or are worried about anything, please speak to the ultrasound appointments team on 01305 254428.

About this leaflet

Author: Helen Derbyshire, Sonographer
Written: November 2018
Updated and approved: May 2025
Next review date: May 2028
Edition: v3

If you have feedback regarding the accuracy of the information contained in this leaflet, or if you would like a list of references used to develop this leaflet, please email patientinformation.leaflets@dchft.nhs.uk