Ultrasound imaging, also called ultrasound scanning or sonography is a method of obtaining images from inside the human body through the use of high-frequency sound waves. The reflected sound wave echoes are recorded and displayed as a real-time visual image. No ionizing radiation (x-ray) is involved in ultrasound imaging.
Ultrasound is a useful way of examining many of the body’s internal organs, including but not limited to the heart, liver, gallbladder, spleen, pancreas, kidneys and bladder. Because ultrasound images are captured in real time, they can show movement of internal tissues and organs and enable physicians to see blood flow and heart valve functions. This can help to diagnose a variety of heart conditions and to assess damage after a heart attack or other illness.
Millions of expectant parents have seen the first “picture” of their unborn child with pelvic ultrasound examinations of the uterus and fetus. Ultrasound imaging is used extensively for evaluating the pelvic and abdominal organs, heart and blood vessels, and can help a physician determine the source of pain, swelling or infection in many parts of the body. Because ultrasound provides real-time images it can also be used to guide procedures such as needle biopsies, in which needles are used to sample cells from organs for laboratory testing. Ultrasound is also used to image the breasts and to guide biopsy of breast cancer, in addition to evaluating superficial structures such as the thyroid gland and scrotum.
Doppler ultrasound is a special technique used to examine blood flow. Doppler ultrasound images can help the physician to see and evaluate:
- Blockages to blood flow (such as clots).
- Narrowing of vessels (which may be caused by plaque).
- Tumors and congenital malformation.
- It is noninvasive (no needles or injections in most cases) and is usually painless.
- It is widely available and easy to use.
- It uses no ionizing radiation and is the preferred image modality for diagnosis and monitoring of pregnant women and their unborn infants.
- It provides real-time imaging, making it a good tool for guiding minimally invasive procedures such as needle biopsies.
- Ultrasound images can visualize structure, movement and live function in the body’s organs and blood vessels.
You should wear comfortable, loose-fitting clothing for your ultrasound imaging exam. Other preparation depends on the type of examination you will have. For some scans you may be instructed not to eat or drink for as many as 12 hours before your appointment. For others you may be asked to drink up to six glasses of water two hours prior to your ultrasound exam and avoid urinating so that your bladder is full when the scan begins.
The following preparatory information will be helpful depending on the location of the study:
- Abdomen – Do not eat or drink anything for the 6 hours prior to your exam.
- Pelvic/OB – A full bladder is required. Drink four to six 8 oz. glasses of water and finish drinking 1 hour before your exam. Do not empty your bladder. Example: Your appointment is for 9:00 am, you should have finished drinking by 8:00 am.
- Renal – 1 hour prior to your exam you must drink 32 oz of water. Do not urinate.