The Value of MR Imaging When the Site of Uterine Cancer Origin Is Uncertain

Purpose: To assess the value of magnetic resonance (MR) imaging in determining the site of origin of newly diagnosed uterine cancer (corpus vs cervix) when clinical and/or histologic evaluation is indeterminate. Materials and Methods: The Institutional Review Board approved and waived informed consent for this HIPAA-compliant study of 59 women (median age, 59 years; range, 28-84 years) who underwent pelvic MR imaging to determine the anatomic origin of uterine cancer. Two radiologists independently retrospectively assessed all MR imaging studies. In 48 patients who underwent hysterectomy, surgical pathologic findings were the reference standard, and overall test yields and diagnostic likelihood ratios were measured. Accuracy in detecting invasion of adjacent structures was also calculated. For the remaining patients, imaging and biopsy findings are presented descriptively. Results: At hysterectomy, 32 patients had uterine corpus cancer and 16 had cervical cancer. Overall test yields for reader 1 and reader 2 were 0.85 and 0.88, respectively. When a reader attributed a tumor's origin to either the uterine corpus or cervix, the odds of the tumor originating from that site were 4.80-6.35 times greater than they would have been if no other information were available. Accuracy levels in detecting invasion of the myometrium, cervical stroma, parametria and/or adnexae, and vagina, respectively, were 72%, 69%, 74%, and 85% for reader 1 and 78%, 77%, 76%, and 85% for reader 2. Conclusion: MR imaging is useful for determining the anatomic origin of uterine cancer and provides helpful information regarding invasion of adjacent structures. (C)RSNA, 2011