Study On Perianal Fistulising Crohn’s Disease And Glandular Anal Fistula Based On MRI And Texture Analysis

Partl:Conventional MRI findings in the differential diagnosis of the perianal fistulising Crohn’s disease and the glandular anal fistulaObjective:To explore the value in the differential diagnosis of the perianal fistulising Crohn’s disease(PFCD)and the glandular anal fistula by comparing the clinical indexes and conventional MR imaging findings of them.Materials and methods:Patients diagnosed with anal fistula after pelvic MRI examination were searched in Picture archiving and communication systems(PACS)from January 2014 to July 2018.124 PFCD patients confirmed by surgical pathology,endoscopic and imaging examination were assessed,including 90 males and 34 females,mean age±standard deviation,(27.9±9.6)years,age range,11-61 years.And 100 glandular anal fistula patients diagnosed by surgical pathology were evaluated,including 89 males and 11 females,mean age±standard deviation,(39.0 ± 13.6)years,age range,15-76 years.Clinical indexes and MR imaging findings were compared.Clinical indexes include gender,age,clinical symptoms and laboratory inflammatory indicators.MR imaging findings include fistula type,internal opening distance from the anal verge,internal opening and exit site,tract diameter,the maximum diameter of abscesses,horseshoe fistula,anovaginal/scrotal fistula,secondary tracts and extension,active proctitis,perianal cellulitis,pelvic cavity accumulates fluid and the enlarged lymph nodes in the inguinal region and around the rectum.Clinical indexes and imaging signs were analysed using independent sample t test or chi-square test,and binary Logistic regression analysis was used to establish the model of clinical indicators,imaging signs and the united model.Diagnostic accuracy was assessed by receiver operating characteristic area under curve(ROC-AUC)analysis.Results:Male patients predominated in both PFCD and glandular anal fistula groups(72.6%,89.0%,respectively;p=0.002).The mean age of the PFCD group was younger than the glandular anal fistula group(p<0.001),and abdominal pain or diarrhea,weight loss,raised erythrocyte sedimentation rate(ESR),C-reactive protein value(CRP)and blood platelet(PLT)was more commom(p<0.001,p=0.029,p<0.001,p<0.001,p<0.001,respectively).Superficial fistula was more commom in the glandular anal fistula group than the PFCD group(p=0.008).Single unbranched tracts were more commom in the glandular anal fistula group(AUC=0.631,p<0.001),however multiple tracts,supralevator and intrapelvic involvement were more commom in the PFCD group(AUC=0.634,p<0.001;AUC=0.568,p=0.007;AUC=0.567,p=0.004;respectively).The internal opening distance from the anal verge was longer(AUC=0.680,p<0.001),multiple internal opening and exist site were more commom(AUC=0.585,p=0.002 and AUC=0.604,p<0.001),the exist site was more diverse(AUC=0.653,p<0.001),the tract diameter was wider(AUC=0.583,p=0.007)horseshoe fistula(AUC=0.547,p=0.030)and anovaginal/scrotal fistula(AUC=0.517,p=0.008)were more commom in the PFCD group than the glandular anal fistula group.Meanwhile,active proctitis(AUC=0.744,p<0.001),perianal cellulitis(AUC=0.5 80,p=0.01 6),pelvic cavity accumulates fluid(AUC=0.611,p<0.001)and the enlarged lymph nodes in the inguinal region and around the rectum(AUC=0.629,p<0.001)were more commom as well.The area under curve(AUC),sensitivity and specificity of the model of clinical indicators,imaging signs and the united model were respectively 0.865,71.77%,88.00%;0.863,79.84%,79.00%and 0.919,85.48%,83.00%.Conclusion:①The patients in the PFCD group were younger than those in the glandular anal fistula group,with more common abdominal pain or diarrhea and elevated CRP.Clinical indicators were of certain value in differentiating these two lesions.②Compared with the glandular anal fistula group,the PFCD group is often manifested as the following MR imaging findings:higher internal opening,multiple internal opening and exist site,diverse exist site,wider tract diameter,horseshoe fistula and anovaginal/scrotal fistula,active proctitis,perianal cellulitis,pelvic cavity accumulates fluid and the enlarged lymph nodes in the inguinal region and around the rectum.The conventional MR imaging findings could help to distinguish between the two types of lesions.③Combined with clinical indicators and imaging findings,PFCD and the glandular anal fistula could be distinguished.Part2:Texture analysis of rectum and anal canal wall in the differential diagnosis of the perianal fistulising Crohn ’s disease and the glandular anal fistulaObjective:To explore the value in the differential diagnosis of the perianal fistulising Crohn’s disease(PFCD)and the glandular anal fistula by comparing the textural feature parameters of rectum and anal canal in fat suppression T2 weighted imaging(FS-T2WI).Materials and methods:The patients with rectal water sac implantation were screened from the first part of this study(48 patients with PFCD and 22 paltients with glandular anal fistula).Open source software ITK-SNAP was used to delineate the ROI of entire rectum and anal canal wall on the axial every section,and then the ROIs were put into the American GE Analysis Kit(AK)software to calculate the textural feature parameters.Textural feature parameter differences of rectum and anal canal wall between the PFCD group versus the glandular anal fistula group were analysed using Mann Whitney U test.The redundant textural parameters were screened by bivariate Spearman correlation analysis,and binary Logistic regression analysis was used to establish the model of textural feature parameters.Finally,diagnostic accuracy was assessed by ROC-AUC analysis.Results:A total 385 textural parameters were obtained,including 37 parameters with statistically significant difference between the PFCD group and the glandular anal fistula group.Then 16 texture feature parameters were remained after bivariate Spearman correlation analysi,including one histogram parameter(Histogram energy),four grey level co-occurrence matrix(GLCM)parameters(GLCM energy_all direction_offset1_DS,GLCM entropy_all direction_offset4_SD,GLCM entropy all direction_offset7_SD and Haralick correlation_all direction offset7_SD),four texture parameters(Correlation_all direction_offsetl_SD,Cluster prominence_angle 90_offset4,Inertia_all direction_offset7_SD and Cluster shade_angle 45_offset7),five grey level run-length matrix(RLM)parameters(Grey level nonuniformity_angle 90_offsetl,Grey level nonuniformity_all direction_offset4_SD,Long run high grey level emphasis_all direction_offsetl_SD,Long run emphasis_all direction_offset4_SD and Long run high grey level emphasis_all direction_offset4_SD),and two form factor parameters(Surface area and Maximum 3D diameter).The AUC,sensitivity and specificity of the model of textural feature parameter were respectively 0.917,85.42%,86.36%.Conclusion:The model of textural feature parameters has a good diagnostic performance for PFCD.The texture feature parameters of rectum and anal canal in FS-T2WI are helpful to identify the PFCD and the glandular anal fistula.