Diagnostic Approach to Endometriosis and Ovarian Cysts

Initial Evaluation and Imaging

The American College of Radiology recommends using ultrasound as the preferred initial imaging modality for further evaluation of ovarian cysts, as it allows for detailed characterization using the O-RADS risk stratification system, differentiates between endometriomas and infected/complicated cysts, and provides real-time assessment without radiation exposure 1
Ultrasound is useful for evaluating signs of torsion or rupture that may require urgent intervention, and for characterizing adnexal masses, which is a limitation of CT scans 2
The O-RADS US risk stratification system classifies typical endometriomas <10 cm as O-RADS 2 (almost certainly benign, <1% risk of malignancy), but further evaluation is needed if there are concerning features (enhancement, edema suggesting infection) 1

The presence of pain with complex cysts warrants thorough evaluation to rule out complications, and ultrasound can assess for signs of infection (increased vascularity, complex internal echoes) and torsion (absent blood flow) 1
If ultrasound confirms infected endometriomas, gynecology consultation, antibiotic therapy, and possible surgical intervention may be necessary 1
If ultrasound shows typical endometriomas without infection, pain management and follow-up imaging in 8-12 weeks may be appropriate 1
If ultrasound shows higher O-RADS classification (3 or above), gynecologic oncology referral may be warranted 1

Superimposed infection can occur in endometriomas and requires prompt treatment, and CT has limitations in characterizing adnexal masses compared to ultrasound or MRI 1, 2
The patient's history of endometriosis increases the likelihood of endometriomas, but does not exclude other pathologies, and other pathologies can coexist with endometriomas 2
Delaying evaluation of potentially infected cysts can lead to abscess formation or sepsis, and overreliance on CT findings alone can lead to misdiagnosis or delayed diagnosis 2