Role of magnetic resonance imaging and apparent diffusion coefficient at 3T in distinguishing between Adenocarcinoma of the uterine cervix and endometrium

Background: To determine whether magnetic resonance imaging (MRI) and apparent diffusion coefficient (ADC) are able to distinguish between adenocarcinoma originating from the uterine cervix and endometrium. Methods: Institutional review board approval and informed consent were obtained. From May 2006 to June 2008, 29 women 25-73 years old (mean age, 50.3 years) with a cervical biopsy yielding adenocarcinoma were enrolled for 3-T MR study with the imaging pulse-sequence protocol of T2-weighted imaging (T2WI) and dynamic contrast-enhanced (DCE) MRI and diffusion-weighted MRI (DWI, b = 0, 1000 sec/mm²). The extent and shapes of the tumor and ADC values were evaluated by two radiologists retrospectively. Surgical histopathology served as the reference standard of the tumor origin from the cervix (n = 22) or endometrium (n = 7). The Mann-Whitney U test was used for statistical comparison and receiver operating characteristic (ROC) analysis was used to obtain optimal ADC cut off values. Results: A longitudinal shape occurred significantly more frequently in endometrial cancer, and an oval shape was more frequently found in cervical cancer (p = 0.011). Mean ADC values were significantly lower in endometrial cancer (76.6 × 10^-5 mm²/sec) than in cervical cancer (96.9 × 10^-5 mm²/sec). Receiver operating characteristic analysis yielded an optimal ADC cutoff value of 70 × 10^-5 mm²/sec to distinguish cervical cancer from endometrial cancer. Conclusion: MRI may distinguish between most uterine adenocarcinoma originating from the cervix and endometrium using distinctive characteristics found on T2WI and DCE. When tumors show an ambiguous morphology, the ADC value of the tumor may be helpful for further differentiation.