OBJECTIVETo evaluate the diagnostic value of preoperative CT enterography (CTE) on obstruction, fistula and abscess formation compared to intraoperative findings in patients undergoing surgery for Crohn's disease(CD), aiming to provide reference to clinical practice.

METHODSPreoperative CTE data of 176 CD patients confirmed by clinic, endoscopy, imaging, operation and pathology at the Department of General Surgery in Nanjing Jinling Hospital from January 2013 to December 2015 were enrolled in retrospective cohort study. All the patients underwent enhanced full abdominal CT scan using SIMENS SOMATOM Definition Flash 64 row dual-source CT machine. CTE scans were performed from the dome of diaphragm to the symphysis pubis. The CT images in arterial and venous phase were reconstructed with 1.0 mm thin layer, and then processed in MMWP 4.0 workstation including multi-planar recombination, surface recombination and maximum density projection. The sensitivity, specificity, positive and negative predictive value, false negative rate and accuracy of preoperative CTE on obstruction, fistula and abscess were compared with intraoperative findings.

RESULTSAmong 176 patients, 122 were males and 54 were females with median age of 29 (18 to 65) years, median disease duration of 48 (1 to 240) months, median time interval from CT scan to operation of 16(1 to 30) days, and median body mass index of 17.8 (10.8 to 34.7) kg/m. Twenty-six cases (14.8%) had nutritional risk (NRS2002≥3); 23 cases (13.1%) had lesions limited to ileum; 19 cases (10.8%) had lesions limited to colon; 126 cases (71.6%) had simultaneous lesions of ileum and colon, and 8 cases (4.5%) had lesion in upper gastrointestinal tract. A total of 199 lesions of small intestine were identified by preoperative CTE, including 131 of obstruction (65.8%), 42 of fistula (21.1%), and 26 of abscess (13.1%), while 235 lesions were confirmed by operation, including 133 of obstruction (56.6%), 74 of fistula (31.5%), 28 of abscess (11.9%). The modification of planned surgical procedure due to unexpected intraoperative findings were found in 29(16.5%) patients. The sensitivity, specificity, positive predictive value and negative predictive value of preoperative CTE were 86.4%, 78.8%, 86.9% and 76.0% for obstruction; 83.8%, 79.1%, 67.5% and 90.4% for fistula; and 96.2%, 98.0%, 90.1% and 99.3 for abscess, respectively.

CONCLUSIONPreoperative CTE can effectively evaluate the lesions of intestinal obstruction, fistula and abscess in CD patients, with the highest accuracy of abscess, and has quite good consistency with intraoperative findings, which may be used as the first choice of imaging diagnosis of CD.