What is an Ultrasound Scan?
Ultrasound imaging, also called ultrasound scanning or sonography, is a method of obtaining pictures or images from inside the human body. It involves sending very high frequency sound waves through the body. These sound waves are reflected off the internal organs.
The reflections are then processed by special instruments and powerful computers that subsequently measure and create a visual image of the organs. Ultrasound images are captured in real time and displayed on a television monitor.
What will happen during a scan?
An ultrasound examination is a painless, usually non-invasive, procedure. There are several methods of performing the examination depending on the part of the body being examined.
In most cases, no special preparation is needed before a routine ultrasound scan. We advise patients to wear loose-fitting and comfortable clothing.
If the doctor wants to check the liver or gallbladder, the patient may be asked to eat nothing (fast) for several hours before the procedure.
For individuals going for a renal scan, the patient will be asked to drink plenty of water and to avoid urinating several hours before the test.
If a pelvic scan is required, the bladder will need to be full, the patient will be asked to drink 1.5 litres of water 1 hour before their appointment. This will displace nearby loops of intestine and the scan produces a better image of the uterus ovaries.
When you arrive for a scan you may be shown to a cubicle and asked to take off your outer clothing. Whether you have to undress or not will depend on the part of your body to be scanned. You will be taken into the scanning room and asked to lie on a couch next to the ultrasound machine.
A clear, waterbased gel will be spread onto your skin over the scanning site. This helps to transmit the sound waves to the microphone in the transducer. The Sonographer will press the transducer onto your skin and move it back and forth over the part of your body that is being scanned. The scan will appear on the machine screen, which will be next to you.
You will be awake throughout the examination.
You may be asked to take deep breaths in or move into different positions to obtain the best possible images. Depending on the type of scan being carried out, the examination will usually take between 10 minutes to half an hour.
At the end of the scan, the sonographer will wipe the gel from your skin and you will be able to get off the couch and put on any clothes you may have removed.
You will be able to go home once the scan is over. Some types of scan may require the transducer (probe) to be used internally. These are typically transvaginal. When scanning the female pelvis, a transvaginal approach is used as it may give superior quality images. For this scan, small pen-shaped transducer is given a protective cover, lubricated with a small amount of gel and then gently inserted into the vagina up to the cervix to get the best image. It should not cause more than a slight discomfort.
When will I find out the results?
The sonographer will analyse the images and send a preliminary of the scan to the Radiologist who will in turn send a report to the referring doctor.
Are ultrasound scans dangerous?
Ultrasound is generally considered a ‘safe’ imaging modality. Medical research has found no side effects. Even so, scanning should not be carried out without clear medical reasons and all ultrasound exposure should be justified and limited to the minimum needed to make a diagnosis.