Endometrial cancer: the role of MRI quantitative assessment in preoperative staging and risk stratification.

Background: New methods to reduce subjectivity in preoperative magnetic resonance imaging (MRI) staging of endometrial cancer are needed.
Purpose: To investigate the role of MRI quantitative assessment in staging and risk stratification of endometrial cancer.
Material and Methods: Preoperative T2-weighted (T2W) images and diffusion-weighted imaging of 42 patients were analyzed retrospectively by two radiologists. Tumor area ratio (TAR) and tumor volume ratio (TVRseg) were calculated by semi-automatic segmentation of the tumor and uterus on T2W imaging and apparent diffusion coefficient (ADC). TVR was also calculated by the 3D metric method (TVRmetric). Mean ADC _tumor was calculated. The patients were allocated to risk groups regarding the stage, grade, and lymphovascular invasion (LVI) status.
Results: TAR, TVRmetric, T2W TVRseg, and ADC TVRseg showed a significant difference between the superficial and deep myometrial invasion groups ( P  < 0.001). All of these parameters showed a good diagnostic performance for detecting deep myometrial invasion (AUC>0.82), the highest accuracy rate (85%) was found with T2W TVRseg. LVI was significantly associated with TAR ( P  = 0.002) and T2W TVRseg ( P  = 0.014), while the cervical invasion was associated with TAR ( P  = 0.03). ADC _tumor was significantly lower in high-grade tumors ( P  = 0.002). There was a significant difference in ADC _tumor ( P  = 0.002), TAR ( P  = 0.004), and T2W TVRseg ( P  = 0.038) between the low- and high-risk groups. AUC of TAR and T2W TVRseg for detecting high-risk groups were 0.80 and 0.77, respectively, while AUC of ADC _tumor for the low-risk group was 0.75.
Conclusion: MRI quantitative assessments such as TAR, TVR, and ADC _tumor may improve the accuracy of preoperative staging and can help in risk stratification of endometrial cancer.