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 from x-ray in that it does not use radiation.
WHAT IS AN ULTRASOUND?
An ultrasound scan uses high-frequency sound waves to make an image of a person’s internal body structures. Doctors commonly use ultrasound to study a developing fetus (unborn baby), a person’s abdominal and pelvic organs, muscles and tendons, or their heart and blood vessels. Other names for an ultrasound scan include a sonogram or (when imaging the heart) an echocardiogram.
The ultrasound machine directs high-frequency sound waves at the internal body structures being examined. The reflected sounds, or echoes, are recorded to create an image that can be seen on a monitor. The sound waves are emitted and received from a small, hand-held probe. The high frequency of the sound means the human ear cannot hear it – which is why it is called ultrasound.
Common reasons for ultrasound scanning include investigations of a person’s abdominal and pelvic organs, musculoskeletal and vascular systems, and checking fetal development during pregnancy.
An ultrasound scan is usually non-invasive (done from outside the body). However, some scans are done with a special probe that is inserted into the person’s vagina (for some obstetric or pelvic examinations), rectum (for some prostate examinations), or esophagus (for some heart examinations). Sometimes, doctors will use ultrasound scanning to monitor and guide invasive procedures like a biopsy of a person’s breast or thyroid gland.
COLOUR DOPPLER
Colour Doppler ultrasound is a special type of ultrasound that is used to look at blood flow.
A Colour Doppler ultrasound machine has a handheld scanner that is connected to a computer. It uses soundwaves to take pictures of the blood flow in your major arteries and veins.
BENEFITS OF COLOUR DOPPLER
- Non-invasive
- Generally painless
- Does not use radiation
- Can show if you have any blocked arteries in your neck, arms, and legs
- Can show if you have any blood clots in the veins in your legs
- Can show the amount and speed of blood flow in your veins and arteries
- Can be used instead of some more invasive procedures
WHEN IS ULTRASOUND 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.
Frequently Asked Questions
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 jewelry 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.
Some ultrasound examinations require special preparation beforehand, such as:
- You may be asked not to eat for a few hours before an upper abdominal scan.
- Some pelvic examinations require you to have a full bladder before the scan.
You will need to ask your doctor or the ultrasound department if you need to do any special preparation before your scan.
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. The 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.
An ultrasound scan usually takes 20 – 60 minutes. It is an outpatient procedure (you will not be admitted to the 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 afterward.
