What is the accuracy of ultrasonography for the evaluation of endometrioma/endometriosis?

Updated: Dec 14, 2018
  • Author: Shawn Daly, MD; Chief Editor: Eugene C Lin, MD  more...
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US scanning is not as specific as MRI in the evaluation of endometriosis. The appearance of a cystic mass with homogeneous, diffuse, low-level echoes is highly suggestive of an endometrioma. However, other appearances are much less specific and can be mimicked by hemorrhagic cysts, tubo-ovarian abscesses, and cystadenomas. [36] US scan characteristics of endometriomas overlap with other pathologies, such as ovarian neoplasms. Endometriomas are commonly bilateral or multicystic, furthering their resemblance to malignancies. [38]

Since small endometrial implants are not seen reliably on US scans, US scanning is not a sensitive technique to diagnose endometriosis.

Guerriero and colleagues found that the sensitivity and specificity of endovaginal ultrasonography were 83% and 89%, respectively, when the technique was used to differentiate endometriomas from other ovarian cysts. [35]

Low-resistance Doppler waveforms resembling malignancy are often encountered in endometriomas. [19, 39]

False-positive findings may occur because hemorrhagic cysts, tubo-ovarian abscess, and cystadenomas may resemble endometriomas. [19, 34, 38]

False-negative findings can occur because endometrial implants are too small to visualize on US scans. In addition, endometriomas without the typical appearance described above may be misdiagnosed as hemorrhagic cysts, tubo-ovarian abscesses, and cystadenomas. [38]

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