Pelvic Ultrasonography Clinical Presentation

Updated: Mar 20, 2016
  • Author: Shoreh Kooshesh, MD; Chief Editor: Gowthaman Gunabushanam, MD, FRCR  more...
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Presentation

History

Evaluation of pelvic pain

Ultrasonography can be used to evaluate pelvic pain, a common presentation in the emergency department. It evaluates emergent entities such as ovarian cysts and rupture, tubo-ovarian abscesses, uterine fibroids, ectopic pregnancy, uterine rupture, and even ovarian torsion. Endovaginal scanning uses a high-frequency transducer and enables optimal imaging of organs close to the probe, including the endometrium, myometrium, cul-de-sac, and ovaries, which can be seen in detail with better resolution. [4, 7, 8, 9]

In a female patient who is obese, pelvic ultrasonography can add to the evaluation of the pelvis, as the physical exam alone will be difficult and have limitations. The endovaginal transducer is preferred for obese patients because it has the ability to visualize pelvic organs far better than any other modality.

The differential diagnosis of pelvic pain should be divided into patients who are pregnant and those who are not pregnant. The most urgent cause of pelvic pain with a positive pregnancy test is an ectopic pregnancy. The worldwide incidence is 1 in 200. Serum beta-HCG levels are not reliable in determining what can be visualized in the evaluation of a pregnant pelvis, and the use of a beta-HCG discriminatory zone in the differentiation of normal and ectopic pregnancy is also unreliable. Endovaginal ultrasonography can detect intrauterine pregnancy earlier than transabdominal ultrasonography. [10, 11, 12]

In nonpregnant patients, ovarian torsion is often a difficult diagnosis of intermittent pelvic pain that must be considered in nonpregnant patients. [5, 13]  An enlarged ovary is the first sign of torsion, while the identification of a complex ovarian mass greater than 5 cm increases the probability of torsion. [14]

Endovaginal scanning is the only modality to assess degree of color flow to and from the ovary and help in the diagnosis of ovarian torsion. [15] Ultrasonography is highly accurate for diagnosing ovarian torsion. One study reported a 74.6% accuracy rate compared with previous reports. [16]

Pelvic masses, including uterine fibroids, ovarian cysts, and cancer, can cause pelvic pain. More rare etiologies of pelvic masses include, but are not limited to, pseudomyxoma peritonei, desmoid tumors, and mesothelial tumors. [17] In order to diagnose the specific etiology of the pelvic mass, further imaging and biopsy are needed.

A prospective, observational study of female patients of reproductive age who required either a physician-performed pelvic ultrasonography (EPPU) or radiology department-performed pelvic ultrasonography (RPPU) for their ED evaluation found that patients who underwent EPPU had statistically and clinically significant reductions in ED length of stay. Forty-eight patients received only EPPU, and 84 patients received only RPPU. Those who received EPPU had an ED length of stay 162 minutes less than those who received RPPU. [18]

Authors of a British study suggested that transvaginal duplex ultrasonography could be the gold standard in assessing pelvic vein reflux. Comparing transvaginal duplex ultrasonography with the outcome from selective treatment of veins identified as having pathological reflux with coil embolization, there were no false-negative diagnoses and only one false-positive. [19]

A retrospective review of patients aged 13-21 years who received pelvic ultrasounds in the ED found that the use of ED bedside ultrasound by trained emergency medicine and pediatric emergency medicine physicians produced a significant reduction in length of stay in the ED, regardless of radiology ultrasound technologist availability. [20]

Evaluation of a pelvic mass

Pelvic ultrasonography can be used to determine the etiology of a pelvic mass. [17, 21, 22, 23]

Compared with endovaginal ultrasonography, transabdominal ultrasonography uses a lower frequency and can penetrate farther, with a large field of view. Thus, fibroids, ovaries, or cysts located high in the pelvis may be out of the focal range of an endovaginal probe. In addition, pelvic kidneys can be visualized.

Uterine fibroids can be diagnosed by pelvic ultrasonography. They may be submucosal, intramural, or subserous. Sometimes they arise from supportive structures of pelvic organs such as broad ligaments. Transabdominal and endovaginal scanning can be done to assess for fibroids. Pelvic masses may also arise from other pelvic organs, including the urinary system, adjacent soft tissues, gastrointestinal system, or even metastases. See below for further discussion on pelvic mass evaluation.

Ovarian cysts can get quite large, can cause torsion, and can rupture. They can be nonhemorrhagic or hemorrhagic, simple or complex. Pelvic ultrasonography can provide the information needed to diagnose and delineate the above complications.

Nabothian follicles or cysts are caused by a dilation of the endocervical glands; they are located in the uterine cervix and are identified as cystic lesions. [17]

Evaluation of vaginal bleeding in early pregnancy

Ectopic pregnancy is the emergent process that must be considered in all pregnant patients who present with vaginal bleeding. [24] This indication is well outlined in the Medscape Reference article Emergent Management of Ectopic Pregnancy. In addition to visualizing an ectopic pregnancy, pelvic ultrasonography can be used to identify a pseudosac. A pseudosac is an empty sac illustrated by an intrauterine fluid collection that forms in response to the hormonal influences of an ectopic pregnancy in the endometrium. When no defintive intrauterine pregnancy is identified, an evaluation of the ovarian and peri-ovarian regions is of the utmost importance. The presence of any abnormalities increases the suspicion of ectopic pregnancy while the absence of ovarian or peri-ovarian abnormalities requires daily follow up ultrasound and beta HCG levels. 

Subchorionic hemorrhage (implantation bleeding) is a common cause of spotting. Depending on the size and location of the hemorrhage, pelvic ultrasonography can be used to diagnose this cause of vaginal bleeding in pregnant patients.

Intrauterine pregnancy can be illustrated using ultrasonography by visualizing a double-decidual sac sign. Pelvic ultrasonography can show a double layer of echogenic deciduas separated by hypoechoic endometrial cavity. [10] It can also show a gestational sac with measured fetal pole and yolk sac, or a gestational sac with beating fetal heart illustrating a live intrauterine pregnancy.

Evaluation of vaginal bleeding post partum

Postpartum hemorrhage (PPH) is the leading cause of maternal morbidity. [25] PPH can be defined as primary or secondary. Primary occurs within 24 hours after delivery. Causes include uterine atony, lower genital tract lacerations, and retained products of conception (this usually presents as late-postpartum hemorrhage). [25]

Retained products of conception can be evaluated using pelvic ultrasonography. [26, 27, 28] The transabdominal ultrasound shows a thickened, heterogeneous stripe or irregular heterogeneous endometrial cavity. [29] Postpartum patients may also present febrile, and if retained products of conception are present, an obstetric/gynecology consultation is warranted for urgent evacuation.

Evaluation of pelvic infection

Pelvic inflammatory disease (PID) is one of the most common causes of acute pelvic pain in sexually active women.

PID should be suspected in all patients with pelvic pain, cervical motion tenderness, fever, and leukocytosis.

Infection can ascend from cervicitis to involve the uterus and fallopian tubes.

If treatment is delayed, the infection can ultimately result in tubo-ovarian abscess. Tubo-ovarian abscesses are difficult to diagnose with physical examination alone.

Endovaginal ultrasound scan. Endometritis with air Endovaginal ultrasound scan. Endometritis with air in the endometrial cavity and bilateral tubo-ovarian abscesses are shown.

A normal fallopian tube may not be visualized with endovaginal ultrasonography; however, a fluid- or pus-filled tube can be identified.

The resulting tubal damage and scarring increases the risk for long-term complications, including infertility and chronic pelvic pain. [10]

Localization of an intrauterine device or foreign body

Ultrasonography can aid in the localization or detection of an intrauterine device or foreign body.

An intrauterine device produces a characteristic acoustic artifact (shadow), which is helpful to the sonographer. [30]

Evaluation of trauma

Ultrasonography is used as a screening tool in all trauma patients who present with blunt or penetrating chest trauma or blunt or penetrating abdominal trauma.

Views of the sagittal and transverse pelvis using the transabdominal transducer are used to evaluate for free fluid or clotted blood, which can be present in the pouch of Douglas (cul-de-sac).

Views of the pelvis obtained before insertion of a Foley catheter are helpful because of the acoustic aid of a full bladder when using the transabdominal transducer.

In cases of significant high-grade-mechanism trauma to the pelvis, the abdomen must always be taken into consideration for evaluation. The focused assessment with sonography for trauma (FAST) examination can be a valuable tool in assessing the unstable trauma patient with blunt abdominal injury, although the diagnostic utility of FAST is less well-defined in primary pelvic trauma. [31]