What is Ultrasound?
Ultrasound (US) imaging, also called ultrasound scanning or sonography, is a method of “seeing” inside the human body through the use of high-frequency sound waves. The sound waves are recorded and displayed as a real-time visual image. No ionizing radiation is involved in ultrasound scanning.
In most ultrasound examinations, a transducer, a lightweight device which produces sound waves, is placed on the patient’s skin. There are also special transducers which can be put into the vagina or rectum to image these areas of the body.
What are the common uses of Ultrasound scanning?
- Abdominal organs e.g, liver, gallblader, spleen, pancreas, kidneys, bladder.
- Pelvic organs e.g., prostate, uterus and ovaries.
- During pregnancy to monitor the development of the embryo or fetus.
- Superficial organs e.g., breast, thyroid, joints(shoulder, ankle).
- Blood Flow. Doppler ultrasound is a special technique used to examine blood flow. Doppler images can help to see and evaluate blockages to blood flow, such as clots, and build-up of plaque inside the vessels.
- Biopsy. It can also be used to guide procedures such as needle biopsies, in which a needle is used to sample cells from an organ for laboratory testing.
How Should I prepare for the procedure?
- You should wear comfortable, loose-fitting clothes.
- For Gallblader examination, a fasting period of 4-6 hours is required to visualize your gallblader, otherwise no fasting is required.
- For pelvic ultrasound, you may be asked to drink up to six glasses of water prior to your exam and avoid urinating, so your bladder is full when the scan begins.
How is the procedure performed?
- You will lie on your back on an examination table
- A clear gel is applied to your body in the area to be examined, to help the transducer make secure contact with the skin. The sound waves produced by the transducer cannot penetrate air, so the gel helps eliminate air pockets between the transducer and the skin. The gel is water soluble, safe and harmless and can easily be wiped off after the scan with a paper tower.
- The radiographer presses the transducer firmly against the skin and sweeps it back and forth to image the area of interest.
- Transvaginal and transrectal ultrasound involves the insertion, lubricated with a small amount of gel and then inserted in the vagina or rectum. The images are obtained from different orientations to get the best views of the uterus and ovaries or the best view of the prostate gland.
- For pelvic ultrasound, it may be done transabdominal or transvaginal to see the uterus and ovaries. Similarly for prostate gland it may be done transabdominal or transrectal.
- When the examination is complete, the gel can be easily cleaned with the use of tissue and you may be asked to dress and wait while the ultrasound images are reviewed.
What will I experience during the procedure?
- Ultrasound imaging is painless, fast and easy. The radiographer will spread some gel on your skin and then press the transducer firmly against your back, moving it ultil the desired images are captured. There may be varying degrees of discomfort from pressue as the radiographer guides the transducer over your abdomen, especially if you are required to have a full bladder.
- There is no pain.
- The examination usually takes about 30 minutes. If blood flow visualization is required, this may take 60 minutes.
When you can expect results
The MRI radiologist and radiographer will review the images during the scan to check that they are clear. The report will be sent to your doctor who will then discuss the scan results with you. Normally it will take 1 to 3 hours for the report.