Inclusion Criteria:  patients were clinically diagnosed with CSP, which was confirmed by surgery and pathological assessment. Patients underwent local resection by hysteroscopy between January 2015 and June 2019 in our hospital. All patients underwent MRI within 3 days before surgery.  Exclusion Criteria:  (1) twin pregnancy ; (2) preoperative methotrexate use; (3) previous incomplete CSP resection performed at other hospitals; (4) Surgical failure with incomplete CSP removal.