A B C D E F G H I J K L M N O P R S T U V W

ULTRASOUND SCANNING - ULTRASOUND IMAGING - ULTRASOUND SCANS

How does Ultrasound Scanning work ?

Ultrasound or "sonar" images are obtained by using sound waves rather than x-rays. The sound waves have a high frequency which cannot be heard by the human ear. The ultrasound pulse is produced in an instrument called a probe. This is attached by a cable to the ultrasound equipment. When placed against or within the body, the probe sends a pulse or burst of ultrasound waves in the direction that the operator wants to "look". The ultrasound waves bounce back from the organ or other structure in the body as a series of echoes. This happens very rapidly. Each pulse of ultrasound lasts about 1/1000th of a second and the echoes are returned within another 1/1000th of a second! These many echoes are used to build up a picture of your internal organs, in much the same way that a navigator picks up the outline of land or another ship using radar.

Why is Ultrasound Scanning performed ?

Ultrasound shows soft tissues like internal organs but not bones. It was first used in pregnant women to check the development of the baby and the condition of the inside of the womb. It is now used in almost all pregnancies. Ultrasound is also used to obtain images of internal organs such as liver, gall bladder, kidneys and urinary bladder. It can be used to obtain images of the prostate gland in men and of the uterus, ovaries and breasts in women. Swellings of the face, neck, body, arms and legs can also be assessed.

Preparations needed prior to Ultrasound Scanning

Some types of ultrasound will require you to have a full bladder. this is particularly valuable for examinations of the pelvic organs. You would then be asked to drink 1 2 pints of water 1 hour before the test and not to pass water until the test is over. On the other hand, you may be asked not to eat or drink anything for 4 hours before the test. However many examinations do not require any special preparation. It is important for you to be sure whether any such preparation is needed when the appointment for the test is made.

What happens during Ultrasound Scanning ?

You will be asked by the radiographer to undress, put on a gown and lie on the examination table. Your gown will need to be arranged so that an area of skin can be moistened with a special oily fluid. The ultrasound "probe" has a smooth round head about 1 inch (2.5 cm) in diameter and the operator will place it gently against the relevant part of the body, moving it around slightly so that the ultrasound beam can explore the necessary area of your body. You will not feel or hear anything. The test is carried out by a radiographer or doctor and takes 10 15 minutes. The skin is wiped dry and the examination is over.

Special types of ultrasound test

Ultrasound guided biopsy is a method for taking a tissue sample from a swelling or organ. It uses the guidance of the ultrasound probe to be sure that the sample is taken from the correct place. It is a valuable test, because it may make an operation unnecessary. It is used to obtain samples of tissue from organs such as the liver, pancreas and kidney. The procedure will always be discussed between you and your doctor before it is carried out and you will be asked to sign a consent form. An injection of local anaesthetic will be given into the skin through a thin needle and this hurts or stings slightly. After a few minutes the skin is numb. The biopsy needle will be carefully passed through the skin and into the appropriate organ. The biopsy needle can be seen by the doctor on ultrasound and will be guided into the appropriate part of the organ. When the sample is being taken you will hear a click. The biopsy needle is then removed, and the sample that was obtained sent to the laboratory for examination under a microscope.

It is sometimes necessary to take two or three biopsy specimens to make an accurate diagnosis. Internal ultrasound examinations are sometimes used in women to examine the uterus (womb) and ovaries. You will be asked to lie on your back while a thin ultrasound probe is passed gently into your vagina. The examination takes 5 10 minutes and the probe is then removed. Images obtained in this way show more detail than those obtained using a probe on the skin. The procedure is slightly uncomfortable but is not painful. Rectal ultrasound examinations are sometimes carried out in men to give detailed images of the prostate gland. You will need to lie on your side while a thin ultrasound probe is passed gently into your rectum. This is uncomfortable but not painful. The probe will be moved around slightly to obtain the best images. Rectal ultrasound examination show the prostate in more detail than examinations carried out with a probe on the skin. Ultrasound-guided biopsy of the prostate gland is sometimes carried out. This will always be discussed between you and your doctor, and you will be asked to sign a consent form. The biopsy needle is passed from the rectum into the prostate using ultrasound to guide the needle. Samples of the prostate are removed and sent to the laboratory for examination. This is a very accurate method of diagnosing early cancer of the prostate. The test is uncomfortable and is occasionally painful. You will always be treated with antibiotics before the biopsy to prevent infection. Biopsy of the prostate takes about 10 minutes.

Possible complications during Ultrasound Scanning

There are no complications from ultrasound except a little tenderness if the ultrasound probe has been pressed on a more tender part of the body. There may be slight discomfort if an internal or rectal examination has been carried out, but these uncomfortable sensations should all be over within a few minutes and you will be able to go home afterwards. However, biopsy has occasional complications even when it is carried out with great care. It can result in pain and occasionally causes infection or bleeding. This might require you to stay in hospital for a day or two after the procedure.

What if Ultrasound Scanning is not performed ?