Evaluating The Inflammatory Activity In Crohn’s Disease Using CT Enterography And Magnetic Resonance Diffusion Kurtosis Imaging

Part 1 The value of CT enterography in quantitative assessment of Crohn’s disease activityObjective To explore the feasibility and the value of CT enterography(CTE)in the quantitative evaluation of Crohn’s disease(CD).Methods Retrospectively analyzed 49 patients diagnosed as CD by clinical,enteroscopy,pathology,and imaging from April 2016 to June 2017 in Zhongnan Hospital of Wuhan University.All patients underwent routine enteroscopy and standardized CTE.The interval between the two examinations was less than 2 weeks.Erythrocyte sedimentation rate(ESR)and C-reactive protein(CRP)levels were measured at intervals.CD patients were classified into inactive,mild and moderate-severe according to Crohn’s disease simplified endoscopic activity score(SES-CD)after enteroscopy.CTE evaluated the site of lesion,the thickness and enhanced patterns of the most severe lesions of the bowel wall,mural enhanced CT value in the portal vein phase,ΔCT value,stenosis,perienteric inflammation,mesenteric hypervascularity(comb sign),enlarged lymph nodes,abdominal abscesses,fistulas,etc.The Chi-square test was used to compare the differences of enhanced patterns among different groups.ANOVA(Analysis of Variance)was used to compare the differences in bowel wall thickness,plain CT values,mural enhanced CT value in the portal vein phase andΔCT values among different groups.The correlation between CTE parameters and SES-CD or laboratory data was analyzed by Pearson(normal distribution data)or Spearman(skewed distribution data).Results SES-CD ranged from 1 to 15,with an average of 5.1±2.6.Among 49 cases,13were inactive,19 were mild,and 17 were moderate-severe.There were 25 cases of intestinal obstruction or stenosis,including 24 cases in the active group and 1 case in the non-active group,and the difference was statistically significant(c~2=13.3,P<0.01).The short diameter of lymph nodes was more than 10 mm in 7 patients,all of them were active patients;32 cases were mesenteric hypervascularity,manifested as“comb sign”,among them,28 cases were active and 4 cases were non-active,and the difference was statistically significant(c~2=9.3,P<0.01).Perienteric inflammation was manifested in 30cases,including 27 cases in the active group and 3 cases in the non-active group,and the difference was statistically significant(c~2=10.8,P<0.01).The enhanced patterns of thickened bowel wall in the non-active was dominated by C and D types,while A and B types was mainly in the active group,and the difference was statistically significant(P<0.05);There were significant differences in bowel wall thickness,mural enhanced CT value in the portal vein phase andΔCT values between different groups(P<0.05),however,the difference of plain CT values between different groups was not significant(P>0.05).Bowel wall thickness,mural enhanced CT value in the portal vein phase andΔCT values were all moderately correlated with SES-CD(r were 0.564,0.585,0.533,respectively;P all<0.01).Bowel wall thickness was positively correlated with ESR and CRP(r were 0.542,0.452,respectively;P all<0.01).Mural enhanced CT value in the portal vein phase andΔCT values were not correlated with ESR or CRP(P>0.05).Conclusion The bowel wall thickness,mural enhanced CT value in the portal vein phase and theΔCT value can be used to accurately assess the activity of CD lesions.Part 2 Evaluating the Inflammatory Activity in Crohn’s disease Using Magnetic Resonance Diffusion Kurtosis ImagingObjectives To explore the feasibility of diffusion kurtosis imaging(DKI)for evaluating inflammatory activity in Crohn’ s disease(CD).Materials and Methods In all,51 CD patients were included,who were performed with consecutive enteroscopy,MR and DKI(b values = 0 – 2000 mm2/s).The lesions of bowel segments were graded as inactive(0–2),mild(3–6),and moderate-severe group(>6)based on simplified endoscopic activity score for Crohn’s disease(SES-CD).To compare the ability of the parameters of DKI and DWI in grading different activity lesions.Results 127 bowel segments including inactive(15),mild(45)and moderate-severe(67)were analyzed.ADC(r =-0.627,P <0.001),Dapp(r =-0.381,P < 0.001)and Kapp(r = 0.641,P < 0.001)were correlated with SES-CD.These parameters were significantly different among the three groups(all P <0.001).ROC analysis found ADC had the highest accuracy(AUC = 0.884,P < 0.001)to differentiate inactive from active group with the threshold at 0.865×10-3 mm2/s,which was slightly higher than Kapp(AUC = 0.867,P < 0.001)with the threshold at 0.645,and was obviously higher than Dapp(AUC = 0.726,P = 0.005).Similarly,ADC also had the highest accuracy(AUC = 0.846,P < 0.001)to differentiate inactive-mild from moderate-severe group with the threshold at 0.825×10-3 mm2/s,and minimally higher than Kapp(AUC = 0.843,P < 0.001)with the threshold at 0.695,and obviously higher than Dapp(AUC = 0.690,P < 0.001).Conclusion DKI is feasible and comparable to conventional DWI for the evaluation of inflammatory activity in CD.