Ultrasound Scans (Sonography)

What is an ultrasound scan?

An ultrasound scan, also known as sonography, is a fast, painless and easy imaging method that uses high-frequency sound waves to acquire images of structures within the human body.

How it works

During an ultrasound scan, a transducer (a lightweight device that produces sound waves), is placed on the patient’s skin or inside the body (such as the vagina or rectum).

These sound waves are recorded and displayed as a real-time visual image. Such images provide diagnostic information for your doctor to diagnose and treat a variety of diseases and conditions.

Why do you need an ultrasound scan?

Ultrasound scans are commonly used to examine:

• Heart
• Blood flow, where a special technique called Doppler ultrasound is used to find and identify blockages to blood flow. These include clots and build-ups of plaque inside blood vessels.
• Embryos or fetuses during pregnancy to monitor their development.
• Abdominal organs, such as the liver, gall bladder, spleen, pancreas, kidneys and bladder.
• Pelvic organs, such as the prostate, uterus and ovaries.
• Superficial organs, such as the breast, thyroid and musculoskeletal joints.

An ultrasound scan may also be used for a biopsy, to guide a needle to obtain tissue samples for laboratory testing.

Benefits of ultrasound scans

Ultrasound scans are:

• Widely available and easy to use
• Non-invasive and usually painless
• Preferred for diagnosing and monitoring pregnant women and unborn babies, as it does not use ionising radiation
• A good tool for guiding minimally invasive procedures such as needle biopsies because of its real-time imaging function
• A good way to visualise structures, movement and live function in the body’s organs and blood vessels

What are the risks and complications of an ultrasound scan?

There are no known harmful effects on humans from standard diagnostic ultrasound scans.

How do you prepare for an ultrasound scan?

You should prepare by wearing comfortable, loose-fitting clothes. If you are preparing for a:

• Gall bladder scan, you should fast for a period of 4 – 6 hours
• Pelvic scan, you should drink up to 6 glasses of water prior to fill up your bladder. Your bladder needs to be full in order for the scan to better visualise your pelvic region.

What can you expect in an ultrasound scan?

During the scan, you will lie on your back on an examination table

A clear gel will be applied to the area of your body to be examined. This helps the transducer to make good contact with the skin. The gel is water-soluble, safe and harmless.

The sonographer will press the transducer firmly against your skin and sweep it back and forth to image the area of interest. By obtaining images in different orientations, the sonographer can get the best views of the target organs.

When the scan is complete, you can clean off the gel easily with tissues. You may be asked to dress and wait while the ultrasound images are reviewed.

Estimated scan duration

The scan usually takes about 30 minutes. If blood flow visualisation is required, it may take up to 60 minutes.