An ultrasound scan creates a real-time picture of the inside of the body using sound waves. Ultrasound is generally painless and non-invasive. Ultrasound works differently to x-ray in that it does not use radiation.
Ultrasound scan types
The common types of ultrasound scan are:
- abdominal ultrasound, which examines the abdomen and other organs and is often used in pregnancy
- transvaginal ultrasound, which examines the female pelvis, kidneys and bladder, uterus, cervix, fallopian tubes and ovaries
- doppler ultrasound, which monitors blood flow in the major arteries and veins
- echocardiogram, which examines the heart
- bone sonography, which assists in the diagnosis of osteoporosis
- 3D ultrasound, which shows a three-dimensional picture of the inside of the body
- 4D ultrasound, which creates a three-dimensional picture in motion
When is an ultrasound scan used?
Ultrasound can be used for screening, diagnosis or to help with treatment. Ultrasound scans can be used to:
- examine organs
- examine tendons and ligaments
- examine lumps to see if they need further testing
- monitor blood flow
- help with treatments, for example by showing the correct site for an injection or a biopsy
Ultrasound has many uses in pregnancy, including monitoring progress and screening for complications. 3D and 4D ultrasound scans are sometimes used in pregnancy for non-medical purposes.
Ultrasounds should only be performed when medically necessary. Speak to your doctor or specialist about whether an ultrasound is required. For more information, visit the Choosing Wisely Australia website.
How is an ultrasound scan performed?
An ultrasound scan is performed using a hand-held scanner, or transducer, connected to a computer. High frequency sound waves are sent into the body. As the sound waves bounce around, the echoes are converted to electrical impulses that show a picture on a screen.
During most ultrasound scans you will be asked to lie on your back or side. Gel will be put on your skin where the scan will take place. The sonographer will move the transducer on the gel. The sonographer may need to press, but you should not feel pain.
If you need to have a transvaginal ultrasound scan you will be asked to empty your bladder and undress from the waist down, with a gown or sheet to cover you. The transducer is slightly larger than a tampon. It will be covered in a protective sleeve or condom and lubricated with gel, inserted into the vagina and gently moved around. Women can request female technicians to perform this type of ultrasound.
An ultrasound scan usually takes 20 – 60 minutes. It is an outpatient procedure (you will not be admitted to hospital), performed by a specially trained doctor or sonographer. There are no after effects and you’ll be able to go about your normal activities afterwards.
How do I prepare for an ultrasound scan?
To prepare for an ultrasound scan:
- bring your referral letter and any ultrasound scan or x-ray results you have received over the past 2 years
- follow the instructions provided to you — you may be asked to fast, or to drink a lot of water and not go to the toilet before the procedure
- leave your jewellery and valuables at home
If you are diabetic it is important that you tell the sonographer before your ultrasound. If you have any questions or concerns, contact the imaging practice for advice.
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Last reviewed: August 2019