Ultrasound

Ultrasound is a scanning technique that uses high frequency sound waves to create images of the inside of your body.  Unlike X-rays, ultrasound doesn't use radiation. 

As a scan is done, the pictures are projected onto a screen to create a moving image. A good example of this is the scanning done during pregnancy that can show images of your unborn baby.

Types of ultrasound

There are 3 main types of ultrasound scans:

• External scan – the ultrasound probe is moved over the skin on the outside of your body. This is the most common type of ultrasound scan.
• Internal scan – the probe is inserted into your vagina or rectum to get a better view of nearby parts.
• Endoscopic scan – the probe is attached to a tube and passed further into the body to examine deeper parts of your body.

Video: What is an ultrasound?

Ultrasound scans can be used to diagnose conditions, to assess the size and function of your organs and to assess and monitor your baby before they're born. They can also be used to guide a doctor or other healthcare provider as they carry out some procedures or surgeries.

Common areas that can be scanned are your: 

• abdomen (tummy/puku)
• breast (see below)
• kidneys 
• liver
• pelvis – in women this commonly checks your ovaries, bladder and uterus wall thickness. In men it can be used to check your prostate, bladder and testicles
• heart – this is done by an ultrasound scan known as an echocardiogram or ECHO
• arteries and veins –  to check the blood flow in your vessels and check for clots
• uterus and baby during pregnancy
• joints – ultrasound of joints can be used to assess the ligaments, tendons and fluid in your joint and also check for arthritis.

Ultrasound scans are often used in real time by healthcare providers doing procedures. Examples of this may be:

• to guide the taking of a breast biopsy (sample of breast tissue) accurately
• to place a tube for people undergoing hospital based treatments
• to assist with correct positioning of a needle when fluid is being injected into, or taken out of a joint.

Why is it done?

A breast ultrasound may be done following a mammogram. It may be used:

• to define a breast lump as solid or fluid filled
• to review a lump that hasn't shown up on a mammogram, or a lump that has been seen on a mammogram but needs further characterisation
• if you have dense breast tissue
• to help isolate and guide a needle into the area of breast where a tissue sample (biopsy) will be taken.

How is it done?

You'll be asked to remove clothing from the waist up and given a gown to wear. The procedure may take up to 30 minutes, but it could, at times, take a few minutes longer.

A trained healthcare professional who is a specialist in ultrasound (a sonographer) will perform the scan.

You'll be asked to lie on your back with your arm raised on the pillow above your head. The sonographer will apply some gel and pass a small handheld transducer over your breast. Gel is required so the ultrasound can transmit into the breast tissue. Part of the transmitted sound waves are reflected back to the transducer and are electronically processed to produce an image of your breast.

Image credit: Mercy Radiology

What are the risks?

Breast ultrasound is a safe procedure well known for its use in scanning babies in utero (before they're born). There's no concern for pregnant or breastfeeding people.

When will I get the results?

The sonographer will discuss the ultrasound findings with the radiologist. Whenever possible you'll be given some early results before you go home. A full written report will follow. Sometimes the radiologist may recommend further testing.

An ultrasound is often quicker, safer and easier to do than more intensive tests such as CT scans. Often an ultrasound will be enough for your doctor to make a diagnosis and plan any next steps or treatments. Some family doctors now have ultrasound machines in their practice to do external scans.  

What happens will depend on what sort of scan you're having.

External scan

An external scan will take approximately 30 minutes and you'll be fully awake through the scan. For some scans you don't need to do any preparation before coming to the hospital, radiology or GP service. If you're having a bladder, kidney or early pregnancy ultrasound, you need to drink 4 to 5 large glasses of water and not go to the toilet. This fills your bladder and makes it easier to see certain areas.

For an external scan you'll usually be asked to lie down on an examination couch. A warm gel is used to improve conduction through the skin by the ultrasound probe (a small hand held instrument) and to help the probe to glide over the skin as it's moved over the area. By changing the angle and position of the probe, the sonographer (ultrasound technician) or radiologist (medical doctor specialising in imaging) can get clearer pictures of the soft tissues inside your body.

Internal scan

These scans are usually done through the vagina or the rectum. A very small lubricated probe is passed gently into the vagina or the rectum for the scan to be done. These scans can cause some discomfort, but they don’t take long and they provide excellent pictures of parts of the body such as parts of the womb (uterus) and ovaries, or your prostate.

Endoscope scan

Your preparation for this scan will be guided by the department doing the scan. Usually you will be asked not to eat or drink anything from midnight the night before, and you may need to take a liquid laxative and liquid diet the day before. It's important that you discuss any medicines that you are taking with the scanning team before the day when you are preparing for the scan. Because you may not be eating on the day before your scan, some of your medicines might need to be changed. 

On the day of the scan you'll usually be given a sedative to help you relax. The scan is done by passing an endoscope, or flexible tube, through your mouth and into your stomach and bowel. This type of scan is uncomfortable, but you will be well supported by the staff performing the scan. Having an ultrasound scan by endoscopy is the same as having an endoscopy. Endoscope scans are very useful tools to enable accurate diagnosis and treatment of a range of internal issues such as cysts, cancers and tumours. Read more about endoscopy.

An endoscope scan will usually take about 30 to 45 minutes. Once it's done you'll be cared for in a recovery room until you're fully awake. You'll be ready to go home about 4 hours after the scan. Make sure you have someone to drive you home and that you're able to rest for the rest of the day. Usually, you can eat and drink within 1 to 2 hours of having the scan. 

If you've had any ultrasounds before and have the reports at home, bring these with you. It can be helpful for the radiologist to compare findings with previous results. If you're having an endoscope scan bring all the medicines that you usually take to the appointment.

If you're having an external or internal scan you can get back to normal activities straight away. If you're having an endoscope scan allow for a day of rest on the day of the scan. A report will be sent to your doctor or hospital clinic and you can arrange a follow up appointment to discuss the results.