An ultrasound scan is a painless procedure that uses high-frequency sound waves to create images of internal parts of the body. There are no known side effects for this medical technology.
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.
Preparing for an ultrasound scan
Before having some types of ultrasound scan, 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 for six hours before the scan – this may be needed before a scan of your digestive system, including the liver and gallbladder.
Depending on the area of your body being examined, you may be asked to remove some clothing.
What happens during an ultrasound scan?
Most ultrasound scans last between 10 and 20 minutes and are performed by a Sonographer. There are different types of ultrasound scans, depending on which part of the body is being scanned and why. The main types are: External Ultrasound scan – the probe is moved over the skin. Internal Ultrasound scan – the probe is inserted into the body
These techniques are described below:
External Ultrasound scan
An external ultrasound scan is used to examine the liver, kidneys and other organs in the abdomen and pelvis, as well as other organs or tissues that can be assessed through the skin, such as muscles and joints. A small handheld probe is placed onto your skin, and moved over the part of the body being examined. A lubricating gel is put onto your skin to allow the probe to move smoothly. This also ensures there is continuous contact between the probe and the skin. You should not feel anything other than the sensor and gel (which is often cold) on your skin. If you are having a scan of your womb or pelvic area, you may require a full bladder, which may cause you a little discomfort. There will be a toilet nearby to empty your bladder once the scan is complete.
Internal (or Transvaginal) ultrasound scan
An internal examination allows the Sonographer to look more closely inside the body at organs such as the ovaries or womb. A “transvaginal” Ultrasound means “through the vagina”. During the procedure, you will be asked to either lie on your back or on your side with your knees drawn up towards your chest. A small ultrasound probe, not much wider that a finger, with a sterile cover is then gently passed into the vagina and images are transmitted to a monitor. Internal examination may cause some discomfort, but do not usually cause any pain and should not take very long.
After an ultrasound scan
In most cases, there are no after-effects and you can go home soon after the scan is finished. The gel is easily removed with a paper towel and will not mark your clothes. You can eat, drink and return to your normal activities straight away. The ultrasound will be reported on the day of the scan and the results will be sent to your GP / Referrer within 48 hours.
Are there any risks or side effects?
There are no known risks from the sound waves used in an ultrasound scan. Unlike some other scans, ultrasound scans do not involve exposure to radiation. External and internal ultrasound scans do not have any side effects and are generally painless, although you may experience some discomfort as the probe is pressed over your skin or inserted into your body.
If you are having an internal scan and are allergic to latex, it is important to let the Sonographer carrying out the scan know this, so they can use a latex-free probe cover.