A pelvic ultrasound is a noninvasive (the skin is not pierced) procedure used to assess organs and structures within the female pelvis. A pelvic ultrasound allows quick visualization of the female pelvic organs and structures including the uterus, cervix, vagina, fallopian tubes, and ovaries. Doppler ultrasound may also show blood flow in certain pelvic organs.
Ultrasound uses a transducer that sends out ultrasonic sound waves at a frequency too high to be heard. When the transducer is placed at certain locations and angles, the ultrasonic sound waves move through the skin and other body tissues to the organs and structures within. The sound waves bounce off the organs like an echo and return to the transducer. The transducer picks up the reflected waves, which are then converted into an electronic picture of the organs.
Different types of body tissues affect the speed at which sound waves travel. Sound travels the fastest through bone tissue, and moves most slowly through air. The speed at which the sound waves are returned to the transducer, as well as how much of the sound wave returns, is translated by the transducer as different types of tissue.
A clear conducting gel is placed between the transducer and the skin to allow for smooth movement of the transducer over the skin and to eliminate air between the skin and the transducer for the best sound conduction.
By using an additional mode of ultrasound technology during an ultrasound procedure, blood flow can be assessed. An ultrasound transducer capable of assessing blood flow contains a Doppler probe. The Doppler probe within the transducer evaluates the velocity and direction of blood flow in the vessel by making the sound waves audible. The degree of loudness of the audible sound waves indicates the rate of blood flow within a blood vessel. Absence or faintness of these sounds may indicate an obstruction of blood flow.
The type of ultrasound procedure performed depends on the reason for the ultrasound. Only one method may be used, or both methods may be needed to provide the information needed for diagnosis or treatment.
Other related procedures that may be used to evaluate problems of the pelvis include hysteroscopy, colposcopy, and laparoscopy.
Pelvic ultrasound may be used for measurement and evaluation of female pelvic organs. Ultrasound assessment of the pelvis may include, but is not limited to, the following:
Pelvic ultrasound can provide much information about the size, location, and structure of pelvic masses, but cannot provide a definite diagnosis of cancer or specific disease. A pelvic ultrasound may be used to diagnose and assist in the treatment of the following conditions:
A transvaginal ultrasound is usually performed to view the endometrium, the lining of the uterus, and the ovaries. Transvaginal ultrasound also provides a good way to evaluate the muscular walls of the uterus, called the myometrium. Sonohysterography allows for a more in-depth investigation of the uterine cavity. Three-dimensional (3-D) ultrasound permits evaluation of the uterus and ovaries in planes that cannot be imaged directly. These exams are typically performed to detect:
Some physicians also use 3-D ultrasound or sonohysterography for patients with infertility. Three-dimensional ultrasound provides information about the outer contour of the uterus and about uterine irregularities.
In men, a pelvic ultrasound is used to evaluate the:
Transrectal ultrasound, a special study usually done to view the prostate gland, involves inserting a specialized ultrasound transducer into a man’s rectum.
In men and women, a pelvic ultrasound exam can help identify:
In children, pelvic ultrasound can help evaluate:
Pelvic ultrasound is also used to guide procedures such as needle biopsies, in which needles are used to extract a sample of cells from organs for laboratory testing.
There may be other reasons for your doctor to recommend a pelvic ultrasound.
A pelvic ultrasound may be performed in your doctor’s office, on an outpatient basis, or as part of your stay in a hospital. Procedures may vary depending on your condition and your hospital’s practices.
Generally, a pelvic ultrasound follows this process:
Ultrasound waves are disrupted by air or gas; therefore ultrasound is not an ideal imaging technique for air-filled bowel or organs obscured by the bowel. In most cases, barium exams, CT scanning, and MRI are the methods of choice in this setting.
Large patients are more difficult to image by ultrasound because greater amounts of tissue attenuates (weakens) the sound waves as they pass deeper into the body.