Imaging Modalities in Gynecology

Transabdominal gynecologic ultrasound combined with transvaginal scanning is a technique that was initially introduced in the early 1980’s and quickly became a “musthave” procedure for gynecologists and emergency room physicians for assistance in diagnosing many gynecologic conditions. Rapid advances in the quality of the equipment, techniques used to obtain best images, and research designed to help physicians interpret their findings have contributed to ultrasound’s quick rise in use and popularity. It is ubiquitous that ultrasound is the imaging modality of choice for gynecologic conditions. The advantages of ultrasound are numerous. It is fast, easy to obtain, has a high patient tolerance and is relatively inexpensive when compared to CT and MRI. Many physicians’ offices have ultrasound machines that are more than sufficient to make common diagnoses thereby alleviating patient anxiety and physician concerns if an abnormality is found during a physical exam. Appropriate referrals and treatments can be initiated in a timely manner at minimum expense. The ability to use the transvaginal ultrasound as an extension of a pelvic exam is extremely useful, particularly when the source of pain is uncertain during bimanual exam or if a mass is found of uterine or ovarian origin. An obvious advantage, especially when compared to CT, is that no radiation exposure occurs. As will be discussed in more detail, pelvic ultrasound has been shown, in numerous studies, to have a high negative predictive value and offers excellent resolution of the uterus and adnexal structures, especially when compared to CT and MRI. There are disadvantages; however, that should be addressed. Even with routine use of transabdominal scanning which utilizes the acoustic window of a full bladder, the field of view is very limited, especially, compared to CT and MRI. Transvaginal sonography limits the field; however, it is effective in obtaining excellent resolution of the uterus, endometrium and adnexal structures. Ultrasound visualizes the bowel poorly and it is well-known that bowel gas corrupts the ultrasound signal allowing for potential “missed” masses not visible under the bowel. An additional drawback is that poor contrast occurs between dissimilar tissues (i.e. blood and fat) making it difficult to characterize certain ovarian masses accurately. Ultrasound characterizes gynecologic pathology extremely well. Fibroids, endometriomas, dermoids, masses that are suspicious for malignancy, uterine anomalies, IUD complications, ectopic pregnancies, and endometrial pathology (with the help of transvaginal saline infusion sonography) are diagnoses that are detected with high accuracy. The following will give illustrations of the clinical utility of diagnostic gynecologic ultrasound for specific clinical conditions. Abstract