Pelvic Ultrasound

Pelvic ultrasound is a noninvasive (the skin is not pierced) procedure used to assess organs and structures within the female pelvis. It 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.

Pelvic ultrasound may be performed using one or both of two methods:

1. Transabdominal (through the abdomen) – a transducer is placed on the abdomen using the conductive gel
2. Transvaginal (through the vagina) – a long, thin transducer is covered with the conducting gel and a plastic/latex sheath and is inserted into the vagina

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.

Reasons for the Procedure

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:

• Size, shape, and position of the uterus and ovaries; thickness, echogenicity (darkness or lightness of the image related to the density of the tissue), and presence of fluids or masses in the endometrium, myometrium (uterine muscle tissue), fallopian tubes, or in or near the bladder; length and thickness of the cervix; changes in bladder shape and blood flow through pelvic organs.
• Pelvic ultrasound in gynecology can provide much information about the size, location, and structure of pelvic masses, and may be used to diagnose and assist in the treatment of the following conditions: abnormalities in the anatomic structure of the uterus, including endometrial conditions; fibroid tumors (benign growths), masses, cysts, and other types of tumors within the pelvis; presence and position of an intrauterine contraceptive device (IUD); pelvic inflammatory disease (PID) and other types of inflammation or infection and postmenopausal bleeding.

Ultrasound may also be used to assist with other procedures such as endometrial biopsy. Transvaginal ultrasound may be used with a procedure called sonohysterography in which the uterus is filled with fluid to distend it for better imaging.