Pelvic ultrasonography is one of the best imaging modalities used to evaluate nonspecific pelvic pain, pregnancy complications, anatomy of pelvic organs, and various ovarian pathologies.
In transabdominal scanning, using a low-frequency transducer, a full bladder is used to displace bowel gas and serve as an acoustic window to improve image resolution and to allow a large viewing field of the pelvis. Endovaginal scanning, using a high-frequency transducer, is the preferred technique for the evaluation of ovarian pathologies, and a full bladder is not necessary.
It also provides higher resolution, which allows better evaluation of the structure, anatomy, and pathology of pelvic organs.
Endovaginal scanning is preferred over computed tomography because of improved visualization of pelvic organs, the absence of radiation exposure with ultrasonography, decreased time of hospital stay, and decreased cost to the patient.
According to the American Institute of Ultrasound in Medicine (AIUM), indications for pelvic ultrasonography include but are not limited to the following
Evaluation of pelvic pain
Evaluation of pelvic masses
Evaluation of endocrine abnormalities, including polycystic ovaries
Evaluation of dysmenorrhea (painful menses)
Evaluation of amenorrhea
Evaluation of abnormal bleeding
Evaluation of delayed menses
Follow-up of a previously detected abnormality
The video below depicts a demonstration of transvaginal ultrasonography.
Demonstration of a transvaginal ultrasonographic pelvic evaluation. Video courtesy of Meghan Kelly Herbst, MD. Also courtesy of Yale School of Medicine, Emergency Medicine.