A Comparative Study Of Magnetic Resonance Imaging Features Between Perianal-Fistulas In Crohn’s Disease And Perianal-Fistulas In Non-Crohn’s Disease

Objective:To investigate the differences of magnetic resonance imaging features between Perianal-Fistulas in Crohn’s Disease(P-FCD)and Perianal-Fistulas in Non-Crohn’s Disease(P-FNCD)and the value of classification in differentiating them.Methods:MRI features of 59 cases of P-FCD and 50 cases of P-FNCD confirmed by operation and pathology were retrospectively analyzed.All patients underwent plain and contrast-enhanced pelvic magnetic resonance imaging.(1)Population data and laboratory examination results of the two groups were analyzed.C-reactive protein(CRP)and Erythrocyte sedimentation rate(ESR)were evaluated in P-FCD group and CRP in P-FNCD group.(2)Six MRI imaging indexes,including the number of branches,the number of abscess,the number of internal orifice,the height of internal orifice,the incidence of proctitis and anusitis,were selected to analyze the MRI data of perianal fistulas in the two groups.(3)The receiver operating characteristic curves(ROC curves)of subjects with age,CRP,number of branches,number of abscesses,number of internal orifice and height of internal orifice were drawn.(4)The perianal fistulas of the two groups were classified according to Parks classification and St.James University Hospital classification,(5)Two groups of patients with perianal fistulas MRI were evaluated according to Van Assche(VA)MR score standard.(6)Six imaging indexes,including the number of branches,the number of abscess,the number of internal orifice,the height of internal orifice,the incidence of proctitis and anusitis,and CRP and ESR,were selected to analyze the perianal fistulas of grade 2 and 4 according to St.James University Hospital classification in P-FCD group.(7)The perianal fistulas in P-FCD group were classified according to the improved classification method,and the differences and correlations among the six imaging indexes,VA,MR score standard,CRP,ESRwere statistically analyzed.Results:There was a significant difference in mean age and CRP between the two groups(p=0.000,p=0.000).There were significant differences between P-FCD group and P-FNCD group in the number of branches,the number of abscess,the number of internal orifice,internal orifice height,incidence of proctitis,incidence of anusitis(p==0.000,p=0.000,p=0.000,p=0.000,p=0.000,p=0.000,p=0.001,p=0.000).The mean values of these six MRI indexes in P-FCD group were obviously higher than those in P-FNCD group.According to St James classification,there was a significant difference between P-FCD group and P-FNCD group(p=0.001).There was significant difference in VA score between P-FCD group and P-FNCD group(p=0.000).The average VA score of P-FCD group was higher than that of P-FNCD group.ROC curve showed five indicators including age,CRP,number of branches,number of abscess,height of the internal orifice and VA score were helpful in diagnosis of P-FCD.The area under the ROC curve of CRP was the largest(0.879),and the diagnostic efficiency was the highest;the area under the ROC curve of VA score was the largest(0.775)in all imaging indexes,and the diagnostic efficiency was the highest in all imaging indexes.In group P-FCD,the proportion of St James grade 2 and grade 4 was 33.90%(20/59)and 44.07%(26/59)respectively.Except for the number of branches and the height of internal orifice,there were significant differences between the two grades of perianal fistula(p=0.018 and p=0.047),there were no significant differences in the other six indexes,such as the number of abscess.There were significant differences in VA score,CRP and ESR among the groups of perianal fistula according to the improved classification method in P-FCD group(p=0.000,p=0.005,,p=0.022)and positive correlation with the grouping(p=0.000,r=0.745;p=0.001,r=0.410;p=0.007,r=0.358).There were significant differences in the number of branches,abscess and internal orifice among the three groups(p=0.002,p=0.001,p=0.016).The number of branches,the number of abscess,the number of internal orifice and internal orifice height were positively correlated with the improved group(p=0.001,r=0.439;p=0.001,r=0.416;p=0.007,r=0.350;p=0.022,r=0.298).Conclusions:The MRI features of P-FCD are multi-branch,multi-absc.ess,multi-internal orifice,high internal orifice,high incidence of proctitis and anusitis.Medical imaging combined with clinical laboratory indexes is helpful for the differential diagnosis of P-FCD and P-FNCD.The combination with clinical data,anal St James classification and VA score can improve the early diagnosis rate of P-FCD.The improved classification corrects some defects of St James classification in P-FCD evaluation,and can correctly reflect the evaluation method of P-FCD activity.It is easy to use and has certain prospects in clinical application.