Supersonic: a guide to ultrasound

Using high frequency sound waves, ultrasound creates live images of an area of the inside of the body. A simple and painless procedure, ultrasound may be used to monitor pregnancy, make a diagnosis of a condition, or for guidance during a surgical operation.

High-frequency: how ultrasound works

Ultrasound, also known as sonography, employs the use of similar technology to radar and sonar normally used to keep track of planes or boats, giving a bat’s eye view into the inside of the human body. As there is no radiation involved, it is more favourable than other technologies for monitoring the development of a foetus during pregnancy.

By using an ultrasound probe, inaudible high-frequency sound waves bounce off parts of the inside of the body creating an echo. These echoes are received by the ultrasound probe and converted into a live image displayed on a monitor for the duration of the scan. The images can be saved and printed for later use.

Why is ultrasound important?

Although ultrasound is mostly related to pregnancy, it has many other uses for doctors. Sometimes ultrasound may be necessary to help make a diagnosis if a patient is experiencing inflammation, pain, or other symptoms. By using ultrasound, a specialist is able to get an internal view of the patient’s organs in order to make an initial diagnosis, such as in an echocardiogram.

During certain operations or medical procedures such as biopsies, ultrasound can also be used to guide surgeons and therefore minimise any internal damage to the patient.

Is it necessary to prepare for an ultrasound?

Some types of ultrasound may require a bit of preparation in order to improve the quality of the image results. A specialist may advise patients to:

• Drink water and avoid going to the toilet until after the ultrasound scan – this gives a clearer image of an unborn baby or pelvic area of the patient
• Abstain from eating for several hours or so before the scan – this may be necessary before carrying out an ultrasound scan of the digestive system, including gallbladder and liver

In some cases, depending on which area of the body is being scanned, it may be necessary to remove clothing and put on a hospital gown prior to an ultrasound scan. Patients may be given a sedative to relax. Depending on what the ultrasound is for, a contrast agent may be administered beforehand in order to make the images clearer.

Supersonic: what happens during a scan?

A special lubricating gel is applied to the skin that is going to be scanned by a sonographer, or ultrasound technician. This allows the ultrasound device, or transducer, to pass over the skin with ease and transmit the sound waves with better clarity.

The transducer emits high-frequency sound waves through the body which are echoed back to a computer. Once the ultrasound scan is complete, the gel is cleaned off and the patient can return to normal daily life straight away. The whole ultrasound procedure lasts around 30 minutes in total.