| Part one.Comparison and analysis of the anal fistula display by different field MR and different MR sequencesPurpose:The clinical diagnosis of anal fistula was taken as the object of study,and the surgical verification was taken as the final result.By comparing the results of different MR fields and different MR sequences on anal fistula lesions,the optimal MR sequences of anal fistula patients were summarized to provide a more reliable basis for clinical surgery.Materials and methods:Preoperative MRI was performed in 41 cases of anal fistula,15 cases were performed with 1.5t MRI and 26 cases with 3.0t MRI.MR scanning sequences included sagittal T2WI(SAG T2WI),axial routine T1WI(AX T1WI),axial T2 fat suppression(AX T2WI-SPAIR),coronal T2 fat suppression(COR T2WI-SPAIR),axial DWI and axial enhanced T1 high resolution isotropic volume examination(e-THRIVE).Results:15 internal opening and 16 tracks were found in the 1.5T group.In the 3.0T group,29 internal opening and 30 tracks were found.There was no statistically significant difference in the presentation rate of the internal opping and fistula between 1.5T MRI and 3.0T MRI(P>0.05).In the display rate of the internal opening,e-THRIVE enhanced scanning was found to be superior to other scanning sequences,followed by ax T2WI-SPAIR sequence.Ax e-thrive enhanced scanning was statistically significant compared with other sequences(P<0.05).In fistula display rate,ax e-THRIVE enhanced scan was also higher than other scan sequences,followed by ax T2WI-SPAIR sequence.Compared with Ax T2WI-SPAIR sequence and cor T2WI-SPAIR sequence,Ax e-THRIVE enhanced scanning showed no statistical significance(P>0.05),and was statistically significant compared with other sequences(P<0.05).Conclusion:1.5T MRI and 3.0T MRI showed no statistically significant differences in anal fistula and fistula.Anal fistula lesions displayed best on axial e-THRIVE enhanced scan,followed by ax T2WI-SPAIR sequence.Part two.Comparison of MRI images of anal fistula with non-crohn's diseasePurpose:By analyzing the MRI images and features of patients with anorectal fistula of Crohn's disease and non-Crohn's disease,this paper explores MRI methods to identify two types of anal fistula.Materials and methods:All the anal fistula patients diagnosed in our hospital and suzhou yongding hospital from January 2015 to May 2018 were selected.According to the inclusion and exclusion criteria,there were 93 cases.Patients were determined to have Crohn disease according to clinical endoscopic radiology and pathological diagnostic criteria,and then the patients were divided into Croh's group(43 cases)and non-Croh's group(50 cases).To observe the Parks classification of fistula,the position of the inner opening,the presence of rectal inflammation and perianal abscess in the two groups;The length of main fistula and branch fistula,the maximum diameter of abscess,the ADC value of fistula lumen,fistula tube wall and anal canal wall were measured.The Van Assche MRI score was calculated.Results:The most common type of fistula was transsphincter type(53.5%in Crohn's group,54.0%in non-Crohn's group),followed by intersphincter type(44.2%in Crohn's group,28.0%in non-Crohn's group).The number of "clock hours "of the anal circumference represented a mean value of 5.4h for the Crohn's group and 6.0h for the non-Crohn's group(P>0.05).The average VA value of the Crohn group was 11.3 points,and that of the non-Crohn group was 10.6 points.There was no statistical difference between the two groups(P>0.05).The mean lengths of main fistula and branch fistula in Crohn's group were respectively 35.5mm and 26.3mm,while those in non-Crohn's group were 45.2mm and 23.3mm.There was no statistical difference between the two groups(P>0.05).The average ADC values of fistula lumen,fistula tube wall and anal canal wall in Crohn's group were 1.045 x 10-3mm2/s,1.217×10-3mm2/s,and 1.361×10-3mm2/s.Non-Crohn's group was 1.036×10-3mm2/s,1.120×10-3mm2/s,1.489×10-3mm2/s.There was significant difference in the ADC values between the two groups(P<0.001).Area under ROC curve was 0.741,sensitivity of ADC value was 54%,specificity was 85%,and threshold was 1.379×10-3mm2/s.There were 15 cases of Crohn's group(34.9%)and 1 case of non-Crohn's group(2.0%)with proctitis,which was statistically significant(P<0.001).In addition,the mean age of patients in the Crohn's group was 27.4 years old,and the average age of patients in the non-Crohn's group was 38.5 years old,showing statistical significance between the two groups(P<0.05).Conclusion:The two groups had similar imaging features,but the presence of rectal inflammation was highly suggestive of Crohn's disease.Complex fistulas are more common in Crohn's disease,and the younger the anal fistula,the more likely it is to be crohn's disease.When the ADC value of anal wall was no more than 1.379×10-3mm2/s,it suggested the possibility of crohn's disease. |
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