Quantitative Analysis Of Messeric Adipose Tissue By Energy Spectral CT Imaging To Evaluate Crohn’s Disease Activity

Objective:To evaluate the activity of Crohn’s disease by analysing messenteric adipose tissuem with energy spectrum CT imaging.Materials and methods:A retrospective study was performed on 127 patients with CD who received energy spectrum CT scanning.The activity of CD was assessed by classical clinical CDAI and these patients were divided into remission group,mild-activity group and moderate and severe-activity group.The slope of spectral HU curve（λHU）,normalized iodine concentration（NIC）and normalized water concentration（NWC）of the creeping fat in the diseased intestine were measured and calculated.The visceral fat area（VFA）and subcutaneous fat area（SFA）of all patients were measured by CT post-processing workstation.The relationship between quantitative data and the CDAI was analyzed.Results:TheλHU、NIC and NWC in moderate and severe CD patients were higher than those in mild CD patients[λHU（-0.49±0.09）vs（-1.24±0.13）,P<0.05;NIC（-4.25±0.96）mg/ml vs（-13.39±2.24）mg/ml,P<0.05;NWC（955.72±5.80）mg/ml vs（931.04±30.25）mg/ml,P<0.05].VFA and VFA/SFA in moderate and severe group were also higher than those in mild group[VFA（79.40±3.58）cm~2vs（74.24±6.57）cm~2,P<0.05;VFA/SFA（1.01±0.05）vs（0.55±0.09）,P<0.05],while SFA in moderate and severe group was significantly lower than that in mild group[（75.57±2.52）cm~2vs（137.78±18.31）cm~2,P<0.05].λHU,NWC and NIC were all positively correlated with CDAI score（wholly P<0.05）,and correlation coefficient ofλHu was 0.881（P<0.001）.The AUC ofλHU,NIC,NWC and VFA/SFA were respectively 0.957（95%CI:0.922～0.993）,0.926（95%CI:0.876～0.977）,0.856（95%CI:0.776～0.936）,0.793（95%CI:0.699～0.879）in the ROC curve of diagnosing moderate and severe group.Conclusions:Energy spectrum CT multi-parameter imaging analysis of messeric adipose tissuemat is an effective method to evaluate inflammatory activity in patients with CD.