What is it and how is it done?
Ultrasound imaging is a non-invasive method of obtaining images of internal images through the measurement of high-frequency sound waves reflecting off of internal organs. It is used to:
View organ development of a fetus
Diagnose gallbladder disease
Evaluate blood flow in blood vessels
Guide a needle biopsy
Check the thyroid gland in your neck
Study the heart
Diagnose an infection
Diagnose some forms of cancer
Reveal abnormalities in the scrotum and prostrate
An ultrasonographer presses a small hand-held device (transducer) against your skin. As the transducer is moved back and forth over your skin, sound waves are emitted that travel into your body. The echoes from these are received by the transducer and then sent to a computer which composes detailed images of the patterns created by the sound waves.
Generally, there are no special preparations required by you other than removing jewelry and all clothing in the area to be examined. If you are having an obstetric ultrasound, your doctor may ask you to drink fluids prior to the examination.
Echocardiography (Ultrasound of the Heart)
This test is used to diagnose or rule out heart disease. It is performed by a cardiac sonographer or your cardiologist. You will lie down on a bed or examination table. Stick-on patches called electrodes are placed on your skin during the test, and the transducer will be put on your chest and abdomen. A small amount of gel is used to make sure there is proper contact between the transducer and your chest/abdomen.
Pictures will be projected on a screen as the transducer is moved and the test is performed. Portions of the test may be recorded for later measurement or interpretation. The examination takes 20 to 30 minutes.
There are no ill effects from the test and no special preparations by you are required.
Ultrasound – Obstetric
This test is used to determine the condition of a pregnant woman and her fetus. You may be instructed to have a full bladder for the test so that the image of the fetus is easier to obtain. You should empty your bladder one hour before the test. Then you may be instructed to drink four to six glasses of water and avoid urinating until the test is completed. This is usually not necessary after the first two to three months of pregnancy.
You will be asked to lie on your back or side and to expose your lower abdomen. The sonographer or radiologist will spread a warm gel over your lower abdomen to help make it easier to move the transducer and allow better transmission of sound waves. Sometimes a transvaginal scan is performed. Instead of the transducer being moved over your abdomen, it will be placed in the vagina. This technique can provide more detailed images. The obstetric ultrasound takes about 20 minutes.
There has been no evidence of harm to the patient or fetus in over four decades of ultrasound testing.
Ultrasound – Venous (Extremities)
A venous ultrasound exam is performed to search for blood clots, usually in the veins of the leg. The transducer is moved over the area interest and the images are projected onto a screen. Sometimes the technician will want to obtain images while you are standing upright but the test is usually performed while you are lying down. The test usually takes no longer than 30 minutes and is generally painless unless your leg is swollen and tender. If that is the case, the pressure from the transducer may add to your discomfort.