Also called sonography or ultrasound scanning, ultrasound imaging uses high-frequency sound waves to obtain images from inside the human body. The process is similar to the sonar used by bats and ships at sea. A small device called a transducer is used to send sound waves into the body, which are then reflected off of internal structures. The returning sound waves (echoes) are then sent back to the same transducer, and the attached equipment changes the echoes into a picture (image) of your internal structures. If your blood flow is what is being studied, audible sound as well as an image can be produced. These continually changing images are recorded on a computer.
Diagnostic ultrasound has been in use for more than 25 years. There are no known harmful effects associated with the medical use of ultrasound.
The procedure itself is painless, but in order to obtain the best image possible, mild discomfort might occur from some transducer pressure or angling. A gel-like substance is applied to the skin surface so that the transducer will have better contact. The gel might be slightly cold but it will not be painful. For some obstetrical and gynecological exams, it might be necessary to place the transducer inside the vagina; however, most women do not find this uncomfortable. In the case of a prostate exam, a transducer is inserted into the rectum; this will not cause any more discomfort than a normal rectal examination.
In most cases, a sonographer or a vascular technologist trained in ultrasound will examine you. He or she obtains and records a series of images. The doctor then reviews the images and may discuss your exam with the sonographer or vascular technologist before issuing an official interpretation. This interpretation may not be available immediately after you have your exam. In some cases, the doctor will also examine you to confirm or resolve uncertain or unclear findings.
Besides pregnancies, ultrasound is used to examine many of the body's internal organs, including the gallbladder, liver, kidneys, pancreas, uterus, ovaries, prostate, testicles, thyroid and breasts. Ultrasound can also look at and listen to the blood flow within arteries and veins in the neck, abdomen and legs. Ultrasound is becoming increasingly important in surgery as a visual aid to the surgeon. Clinicians around the world are constantly finding new applications for ultrasound.
Doppler ultrasound is a special form of ultrasound. This type of ultrasound is useful in evaluating blood flow to the pelvic organs and other body parts. The doctor, vascular technologist or sonographer performing the scan can display this information in several ways. An audible sound can be used, or the blood flow can be shown as a graphic or color display. It is not painful. The decision to use Doppler ultrasound frequently will be made at the time of the exam.