Ultrasound can be useful in helping diagnose the cause of pelvic pain and is often used along with computed tomography (CT).
Abdominal and pelvic computed
tomography (CT) and pelvic ultrasound (US) cross-sectional imaging
are effective tools for detecting the cause of acute pelvic pain in
nonpregnant women, according to the results of a retrospective study
presented at the annual meeting of the American Roentgen Ray Society
(ARRS) in Vancouver, British Columbia.
To assess the performance of CT and US in diagnosing acute pelvic pain and predicting the need for surgery, investigators reviewed the records of 157 women (mean age, 32 ± 10 years) who had presented with pelvic pain at the Harborview Medical Center emergency department and urgent care clinic in Seattle, Washington.
Abdominal and pelvic CT or pelvic US was performed first in 71 and 86 patients, respectively, and yielded a wide range of findings such as ovarian cysts, gynecologic masses, appendicitis, and normal studies.
Approximately two thirds of the imaging studies had positive findings, and CT and US were helpful for making the final diagnosis in 80% of patients. Twenty of the 32 remaining patients were subsequently diagnosed with confirmed or presumed pelvic inflammatory disease or urinary tract infection.
"Although imaging did not provide the final diagnosis in 20% of patients, it should be noted that the studies may have allowed the clinicians to exclude other diagnoses," lead author Dawn Hastreiter, MD, PhD, a radiology resident at Harborview Medical Center, told Medscape.
In 33 patients (21%), an opposite imaging study was performed during the same hospitalization. Of the 8 patients who had undergone US followed by CT, the CT changed the US-negative diagnosis in 3 cases, of which 1 case required surgery for emergent appendicitis. Of 25 patients who underwent CT first, subsequent US changed the diagnosis in 1 case and was considered by investigators to better reflect the diagnosis in 5 cases.
"A limited number of patients had both a CT and US if there was still a clinical question after the first imaging modality," Dr. Hastreiter said. "Similar to the findings of another paper presented at ARRS, we found that CT after US was more beneficial than US after CT."
Surgery was required in 21 patients at 0 to 220 days after presentation; the sensitivity and positive predictive value of CT and US for surgery were above 0.80, and the specificity and negative predictive value were greater than 0.97.
"The high positivity of the studies suggests that our clinicians are doing well in deciding which patients require imaging, and that CT and US are helpful in determining the diagnoses," Dr. Hastreiter pointed out.
Because of the small study sample size, it remains unclear whether either method is more effective than the other for achieving diagnoses, Dr. Hastreiter said. "We would encourage other institutions to publish their experience with CT vs US for acute pelvic pain to better answer this question."
Dr. Hastreiter advises clinicians to consider the need for imaging studies in patients presenting with acute pelvic pain. Because simple urinary tract infections and uncomplicated pelvic inflammatory disease often have normal imaging, laboratory tests and clinical history may be more effective for diagnosing these conditions.
In patients for whom imaging is indicated, the method chosen should reflect the suspected diagnosis. "Although US is often ordered because it poses no radiation risk to the patient, CT is generally believed better for patients with suspected appendicitis, suspected urinary stones, known malignancy, and suspected postsurgical complications," Dr. Hastreiter observed.
"In addition, emergency room physicians, gynecologists, and radiologists need to become more confident in the diagnosis of gynecologic conditions on CT, if a patient happens to get that study," Dr. Hastreiter added, noting that there is increasing evidence of diminished added value in the immediate term in performing US if CT demonstrates gynecologic findings.
"Finally, most physicians know that appendicitis can be missed on pelvic ultrasound, so if appendicitis is still a consideration after a negative US, CT should be performed," Dr. Hastreiter concluded.
This was written by Yael Waknine for Medscape Medical News.
ARRS 2006 Annual Meeting: Abstract 13. Presented May 1, 2006.
Ovarian torsion can cause acute pelvic pain. The ovary becomes twisted on its ligaments and blood flow is cut off to the ovary.
Pelvic pain can because by pelvic inflammatory disease. While this is not an ultrasound diagnosis, in advanced cases, ultrasound can visualize tubal ovarian abscesses or see secondary signs such as pelvic fluid or fluid in the endometrial cavity.
Endometriosis is the condition where endometrial tissue implants itself outside the uterine endometrial cavity. It responds to normal hormonal cycles and can cause pain due to bleeding that occurs during the menstrual cycle. Normally these implants are too small to visualize with ultrasound, but sometimes there is sonographic evidence of endometriosis. An endometrioma is a mass within an ovary caused by the bleeding endometrial tissue.
Pelvic pain can also be caused by ovarian masses.
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