What is Ultrasound Imaging?
Ultrasound imaging, also called sonography, is a method of obtaining images from inside the human body through the use of high frequency sound waves. Ultrasound can be used to diagnose and evaluate disease processes, and can also be used to guide biopsies and other procedures. There is no exposure to X-ray or magnetic waves, which makes ultrasound safe to use in pregnant patients and patients with implanted medical devices.
What are some common uses of Ultrasound?
- Viewing an unborn fetus.
- Examining many of the body's internal organs, including the liver, gallbladder, spleen, pancreas, uterus, ovaries, kidneys and bladder.
- Evaluating the heart (called an Echocardiogram) and blood flow within arteries and veins (called Doppler ultrasound).
- Guiding procedures such as needle biopsies.
- Imaging the breast and guiding breast biopsies.
- Evaluating superficial structures, such as muscles and joints, the thyroid gland and testicles.
How should I prepare for an Ultrasound?
- Wear comfortable, loose-fitting clothing.
- Many types of ultrasound require no preparation at all.
- Depending on the type of ultrasound exam you have, you may be asked:
- Not to eat or drink for six hours before your appointment, or
- Drink 24 ounces of water 1-2 hours prior to your exam and avoid urinating. This will ensure a full bladder when the exam begins.
What should I expect during my ultrasound examination?
The examination typically takes less than 30 minutes and is usually painless. The patient is positioned on the exam table and a warm clear gel is applied to the skin. The gel helps the transducer (ultrasound probe) make contact with the skin. The technologist firmly presses the transducer against the skin and moves it back and forth to image the area of interest.
Generally, the technologist will review the ultrasound images with the radiologist before the patient is discharged from the office. The radiologist may choose to take additional images. Your results will be available from your doctor within 24 hours.
During the first trimester of pregnancy, your doctor may refer you for an "Ultrascreen", which is a screening test for chromosomal abnormalities such as Down's Syndrome. This test requires no preparation and may be performed with an empty bladder. The length of the fetus and the thickness at the back of the neck of the fetus are measured using ultrasound. A blood sample is obtained from the mother using a finger stick. The ultrasound measurement and blood sample are analyzed within 48 hours. Your doctor will receive the report and will determine if any further testing is required.
During the second trimester, at approximately 20 weeks, a "Level 2" or "Fetal Survey" ultrasound may be performed. As preparation, you will be asked to drink normally and not empty your bladder for one hour before the study. First, a technologist will obtain measurements of the fetus. Next, the radiologist will thoroughly examine all the parts and organs of the fetus and will show these to you (and any family or friends who may accompany you). The doctor will discuss any findings requiring additional evaluation or follow up. If possible, 3-Dimensional images of the fetus will be obtained and will be given to you as a keepsake. Occasionally, additional images will be obtained using an endovaginal transducer (ultrasound probe which is inserted into the vagina).
During the later part of pregnancy, ultrasound may be performed to evaluate the fetus for growth, assess the amount of amniotic fluid or follow up a finding from an earlier study.
Pelvic ultrasound may be performed "transabdominally" or "endovaginally". Frequently, both types of ultrasound are performed during the same examination. During a transabdominal ultrasound, images of the uterus and ovaries are obtained through skin of the lower abdomen. This test requires a full bladder, and the patient is asked to drink 24 ounces of water 1-2 hours before the study and not to urinate. An endovaginal ultrasound is performed using an ultrasound probe which is inserted into the vagina. In general, endovaginal images provide more detailed information than transabdominal images, since the transducer is closer to the uterus and ovaries. The examination is not painful and is performed with an empty bladder.
What will I experience during a Sonohysterogram?
A Sonohysterogram is a special kind of pelvic ultrasound which is performed to evaluate the lining of the uterus (called the "endometrium"). During this examination, the radiologist inserts a tube into the uterus, through the vagina, and infuses saline into the uterus while endovaginal ultrasound images are obtained. There is no preparation required. Patients who may be pregnant should have a pregnancy test performed before the procedure, since the test could be harmful to a fetus. Patients who require antibiotic prophylaxis for procedures such as dental work should take their regular prophylaxis before the sonohysterogram.
For more information on this topic, please visit www.Radiologyinfo.org.