| Objectives:1.To explore the ability of CTE conventional CT signs in estimating the nature of CD intestinal stenosis..2.To explore the diagnostic value of quantitative parameters of contrast-enhanced dual energy CT imaging in CD intestinal stenosis,such as CT value of arterial and venous phase,iodine concentration,NIC and spectral curve slope.Methods:Collected cases from the Department of Gastroenterology and Gastrointestinal Surgery at the First Affiliated Hospital of Kunming Medical University from January 2014 to June 2017 with CTE double-energy double-enhanced scan,pathological and clinical comprehensive diagnosis of CD,which included 34 CD cases,53 segments of narrow bowel.According to the pathological gold standard,53 lesions were divided into inflammatory stenosis group with 30 segments and fibrous stenosis group with 23 segments.Patients with normal colonoscopy and CT imaging were treated as normal intestine and 30 segments were collected.By reading the axial,coronal,sagittal,and maximum density projection(Maximum Intensity Projection,MIP)of CTE imaging in the arterial phase,the occurrence probability of different imaging signs(stratified enhancement of intestinal wall,"comb sign",lymphadenectasis,peripheral fibrous hyperplasia,fistula,abscess)in inflammatory and fibrous stenosis was recorded.The arterial phase,iodine phase diagram,single energy diagram and energy spectrum curve diagram were obtained by the dual-energy software of the post-processing workstation.The CT value,iodine concentration,normalized iodine concentration(NIC),energy spectrum slope value(K)of normal intestinal segment,inflammatory stenosis segment,fibrotic stenosis in arterial phase and venous phase were measured and calculated.SPSS 21.0 software was used for data analysis.Pathological results were used as the gold standard.The X2 test was used to analyze the correlation between each image sign with inflammatory stenosis and fibrotic stenosis.A single factor analysis was used to compare the differences in the quantitative parameters of normal intestinal segment,inflammatory stenosis segment,fibrous stenosis segment in artery and the venous phase,the diagnostic efficiency of the quantitative parameters was analyzed by the ROC curve.Results:1.In the arterial phase of CTE imaging,stratified enhancement of intestinal wall(P = 0.000),"comb sign"(P = 0.000),and lymphadenectasis(P = 0.004)were more common in inflammatory stenosis,peripheral fibrous fat.Hyperplasia(P=0.586),fistula(P=0.573),and abscess(P=0.313)were not significantly different in inflammatory stenosis and fibrous stenosis.2.In arterial phase,the CT values of the inflammatory bowel segment and the fibrotic bowel segment were 93.12±8.57Hu and 71.8±4.39Hu,respectively.In venous phase,CT values were 85.34±7.96Hu and 74.97±5.69Hu,respectively.The difference of CT value between the two phases was statistically significant(P<0.05).The iodine concentration in the arterial phase of the inflammatory bowel was 2.22±0.17 mgI/ml,the venous phase was 2.05±0.22 mgl/ml,and the iodine concentration in the fibrotic intestine was 1.74±0.14 mgI/ml and 1.94±0.25 mgl/ml,respectively.NIC of inflammatory segment in arterial and venous phase were 0.15±0.02 mgl/ml and 0.34±0.08.NIC of fibrous segment in arterial and venous phase were 0.13±0.03 mgI/ml and 0.32±0.03 mgl/ml,respectively.The K values of the inflammatory segments in arterial and venous phase were were 2.35±0.31 and 2.22±0.25,respectively,and the K values of the fibrous segments in arterial and venous phase were 2.09±0.33,2.16±0.36.There were significant differences in iodine concentration,NIC and K values between inflammatory segments and fibrous segments in arterial phase(P<0.05).There was no significant difference in iodine concentration,NIC and K value between the two groups in venous phase(P>0.05).3.The iodine concentration,NIC and K values in the arterial phase were the main criterions for the inflammatory stenosis.AUC was 0.776,0.616 and 0.729,respectively.The optimal threshold,sensitivity,and specificity were:iodine concentration 1.99 mgI/ml,69.7%,73.3%;NIC 0.12 mgI/ml,88%,52.2%;K 2.21,66.7%,77.3%.Conclusions:1.The double energy,double phase enhanced CTE examination of Krohn’s disease can not only provide conventional imaging data,but also more images and quantitative parameters,such as double energy iodine map,single energy spectrum and energy spectrum curve,which can enrich the diagnostic information..2.stratified enhancement of intestinal wall,"comb sign",and lymphadenectasis in CTE images of the arterial phase indicate that inflammatory stenosis is the main lession,while peripheral fibrous fat Hyperplasia,fistula,and abscess t are not characteristic in differentiating the inflammatory and fibrous stonosis.3.Iodine concentration,NIC and K value of dual energy CT in arterial phase have certain value for estimating the CD intestinal stenosis.The diagnostic efficacy of iodine concentration in arterial phase is higher than that of NIC and K value. |
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