The Study Of MRC Combine With Fecal Calprotectin In The Diagnosis Of Degree Of Ulcerative Colitis

Objective To discuss imaging features of magnetic resonance colonography（MRC） in ulcerative colitis（UC） and investigate the diagnostic value of MRC combine with fecal calprotectin（FC） in severity of UC. Methods patients diagnosed with UC from Aufust 2015 to February 2016 as case group（n=17）, healthy people without any disease of digestibe tract as the control group（n=8）. All patients underwent endoscopy（reference standard）, MRC, FC and clinical disease activity assessment. Large intestine of all patients were divided into 5 segments, respectively for ascending colon, transverse colon, descending colon, sigmoid colon and rectum. Endoscopic activety was evaluated on a segment basis using the Baron score（BS）, and classified as normal, mild to moderate lesions（no ulcers） or severe lesions（ulcers）. MRC parameters, such as wall signal intensity postgadolinium(WSI_post), relative contrast enhancement（RCE）, wall thickness, the comb sign, mural edema and enlarged lymph node, were observed and logistic regression analysis was used to pick up which one was the best predictive factor for severity. Diagnosis efficiency of MRC index and FC for severity was judged by receiver operating characteristic（ROC） curve. The severity of UC Patients were assessed using Mayo activity index. Results（1）Mean（continuous variables）or the frequency（binary variables）of MRC parameters increased with severity of endoscopic intestinal segment, and the differences between groups has statistical significance（P < 0.05）.（2） Independent predictors for endoscopic activity on a segment basis were comb sign（P = 0.000）, RCE（P = 0.005） and edema（P = 0.028）through logistic regression analysis, correlation between MRC index calculated according to the corresponding coefficiention of predictors and BS was strong and significant（r=0.756, P=0.000）, MRC index detected endoscopic active lesions with high diagnostic accuracy, sensitivity 98.0%, specificity92.3%, AUC was 0.979（95%CI 0.907-0.999, P=0.000）;MRC index detected severe lesions also with high diagnostic accuracy, sensitivity and specificity was 86.1% and 82.1% respectively, AUC was 0.881（95%CI 0.776-0.949, P=0.000）.（3）Consistency between general MRC score（MRC-G） and general Baron score（BS-G） was strong and significant（r=0.854, P=0.001）.（4）Consistency between FC concentrations and BS-G was strong and significant（r=0.819, P=0.000）. FC detected endoscopic active lesions with high diagnostic accuracy, sensitivity 100.0%, specificity 100.0%, AUC was 1.000（95%CI 0.832-1.000, P=0.000）, according to ROC curve analysis and detected severe lesions also with high diagnostic accuracy, sensitivity 87.5%, specificity 100%, the corresponding AUC was 0.958（95%CI 0.764-0.999, P=0.000）.（5）Consistency between Mayo and BS-G was extremely strong and significant（r=0.788, P=0.004）.（6）The diagnosis accuracy of Mayo, MRC, FC for severe UC successively increased, MRC cobining with FC is higher than any single diagnosis way, up to 100%. Conclusions Both MRC index and FC concentrations were demonstrated a high value in the diagnosis of severity of UC patients, and combination of the two will improve the accuracy in the diagnosis of severity of UC patients, which could provide a noninvasive, convenient, easy to follow up method in the diagnosis of severity of UC patients.