Materials and methods
This retrospective cross-sectional study was approved by the ethical committee of The Fourth Affiliated Hospital of Zhejiang University School of Medicine (08/22/2019, No. K20190046). The requirements for informed consent were exempted. An electronic search of the radiology information system was performed in two hospitals between July 2018 and June 2019 and included all consecutive female inpatients who underwent pelvic MRI. The demographic information was collected from the medical records.