Jonathan Rodger Wood MD, Presenter: Nothing to Disclose

Ryan Becton Schwope MD, Abstract Co-Author: Nothing to Disclose

Christopher Joseph Lisanti MD, Abstract Co-Author: Royalties, Lippincott Williams and Wilkins

Pelvic ultrasound is the most commonly used imaging modality for assessment of a wide variety of gynecologic symptoms. However, the ovaries may not be visualized sonographically secondary to technical and patient factors. This may result in a diagnostic dilemma, particularly if the patient’s symptomatology is on the same side as the nonvisualized ovary. In the event that the ovaries are not visualized with pelvic ultrasound, further evaluation is sometimes performed with pelvic MRI. The purpose of this study is to assess the utility of pelvic MRI in the event that either one or both ovaries are not visualized by pelvic ultrasound.

Between March 2007 and December 2010, over 1,500 pelvic MRIs were performed at our institution. The MRI reports were reviewed with comparison combined transabdominal and endovaginal pelvic ultrasounds that had been performed in the preceding 6 months indicating at least one of the ovaries was not seen. Patients with known ovarian malignancy were excluded from analysis. The number of nonvisualized ovaries which where visualized at pelvic MR was recorded and ovarian findings categorized as concordant or discordant. Analysis of data was performed utilizing probability estimates in rare events.

The reports of 245 female pelvic ultrasounds (average age: 49.9 years; range: 21-85 years) were ultimately reviewed indicating that 358 ovaries were not visualized and followed up with MRI. Of these ovaries, 353 had no findings on MR, and 5 ovaries had benign findings. None of the nonvisualized ovaries were found to have suspicious features on MRI. Utilizing the modified Wald equation at a 95% confidence interval, the risk of detecting a clinically significant ovarian finding on pelvic MR when an ovary is not visualized on pelvic ultrasound ranges from 0-1.3%.

Ultrasound is a robust screening technique for ovarian pathology. If an ovary is not visualized on pelvic ultrasound, it can be assumed to be without pathology and MRI adds little, if any, additional information.

Pelvic MRI is not needed to evaluate ovaries that are not visualized sonographically. This information has the potential to reduce imaging costs and improve resource allocation.

Wood, J, Schwope, R, Lisanti, C, Utility of Pelvic MRI after Nonvisualization of the Ovaries by Pelvic Ultrasound.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11002323.html