Ultrasound scanning

An ultrasound scan, sometimes called a sonogram, is a procedure that uses high frequency sound waves to create an image of part of the inside of the body, such as the heart.

As sound waves are used rather than radiation, the procedure is safe. Ultrasound scans are commonly used during pregnancy to produce images of the foetus. They can also be used to detect heart problems, examins other parts of the body such as the liver, kidneys and abdomen, or to help to guide a surgeon performing some types of biopsy.

Take between 15 and 45 minutes. Scans will generally take place in an x-ray department in hospital and be performed by a doctor or sonographer. 

Before having some types of ultrasound scan, you may be asked to follow certain instructions before the procedure, such as drink water and not go to the toilet until after the test. There are three main types of ultrasound scan:

• external
• internal
• endoscopic.

Most often used to examine your heart or an unborn baby in your womb. A small handheld device called a transducer is placed onto your skin, and moved over the part of the body being examined. 

A lubricating gel is put onto the skin, it allows the transducer to move smoothly ensuring there is continuous contact between the sensor and the skin. The transducer is connected to a computer and a moniter. Pulses of ultrasound are sent from a probe in the transducer, through your skin and into your body. They then bounce back from the structures of your body to be displayed as an image on the moniter.

An internal examination allows a doctor to look more closely inside the body at organs such as the prostate gland, ovaries or womb. An ultrasound probe is placed into the vagina or rectum and images are transmitted to a screen. Internal examinations may cause some discomfort but do not usually cause any pain.

Endoscopic ultrasound is where a long, thin, flexible tube called an endoscope is inserted into your body, usually through your mouth, to examine areas such as your stomach, food pipe or the lymph nodes in the chest.

It has a light and an ultrasound device on the end. Once it has been inserted into the body, ultrasound waves are used to create images in the same way as an external ultrasound.

You're usually given painkillers and a sedative to keep you calm as endoscopic ultrasound can be uncomfortable or make you feel sick.

Ultrasound waves cannot pass through bone, air or gas. This means they are unable to produce clear and detailed images of some parts of the body, for example the brain, because it is surrounded by bone.

Other methods, such as barium tests, computerised tomography scans and magnetic resonance imaging scans can be used to examine parts of your body not suitable for ultrasound scanning. 

Advantages

• Safe
• Quick image
• Can see movement

Disadvantages

• Cannot pass through bone/air/gas.
• Unable to produce clear and detailed images of some parts of the body eg. the brain because it's surrounded by bone.