To evaluate the diagnostic value of MR enterography (MRE) and pre-scanning nursing care for the characterization of enteric-urinary fistula in Crohn's disease(CD).

The preoperative MRE of 22 CD patients with enteric-urinary fistulas who underwent surgery were retrospectively analyzed. The location and morphology of the enteric-urinary fistulas were observed on MRE, and the pre-scan nursing care, scan protocol and surgical records were reviewed on the electronic medical record. Using the intraoperative findings of enteric-urinary fistulas as reference standard, the strengths and weaknesses of MRE and the influence of pre-scan nursing care for diagnosing enteric-urinary fistulas were respectively analyzed.

Of 22 patients, 16 had enteric-bladder fistulas and 5 had enteric-ureteral fistulas on MRE, while 18 had enteric-bladder fistulas and 15 had enteric-ureteral fistulas in surgery. The accuracy of MRE was high for the detection of enteric-bladder fistulas (AUC=0.944, P=0.006) but low for enteric-ureteral fistulas (AUC=0.667, P=0.217). The accuracy of MRE in the patients who did not receive standard pre-scan nursing care (0/5) is significantly lower than those who received standard pre-scan nursing care (12/17) (P=0.010).

The diagnostic value of MRE is high for the enteric-bladder fistulas but low for the enteric-ureteral fistula. A standard pre-scan nursing care can improve diagnostic accuracy by enhancing the MR images quality.