Evaluation of anal canal morphology with MRI in cases with anal fissure

Transcription

1 Evaluation of anal canal morphology with MRI in cases with anal fissure Poster No.: C-1670 Congress: ECR 2015 Type: Scientific Exhibit Authors: A. Erden, E. Peker, Z. B#y#kl# Gençtürk, I. Erden; Ankara/TR Keywords: Pathology, Normal variants, MR, Gastrointestinal tract, Abdomen DOI: /ecr2015/C-1670 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 22

2 Aims and objectives Anal fissure is a vertical tear between dentate line and anocutaneous junction ( Fig. 1 on page 2 ). It is located at the posterior midline in the %90 of the cases. One of the reasons of its presence at this location is that the superficial external anal sphincter gets far away from the anus and moves towards the coccyx at the posterior. This part which is called "Minor triangle" is unsupported and may be damaged during faeces passage. Increase of the internal anal sphincter tonus and ischemia of the posterior commisure of anoderm are the other possible causes of the fissure. In our study, we aimed to compare the parameters below, between anal fissure cases and control group; Thicknesses of internal-external anal sphincter muscles and longitudinal muscles, Anorectal angle, Anal canal length, Transvers diameter of anococcygeal raphe, Depth of Minor triangle ( Fig. 2 on page 3 ), Distance between bilateral subcutaneous external sphincters, Vascularity of posterior commisure, Angle between the anal canal and superficial external sphincter muscle (K and B angles) Images for this section: Page 2 of 22

3 Fig. 1 Page 3 of 22

4 Fig. 2 Page 4 of 22

5 Methods and materials Patient group consisted of, 26 cases with acute or chronic fissure. Anal fissure presence was determined from the patient's history, physical examination and colonoscopy reports which were collected from the hospital information database. Patient group consisted of 15 women and 11 men, with a mean age of 44. Control group consisted of 12 women and 13 men, totally 25 cases with a mean age of 49. MRI Technique MRI was performed with 3.0-Tesla MR scanner (MAGNETOM Verio, Siemens, Erlangen, Almanya), using standard body-matrix coil. MRI protocole: T2 weighted sagittal and axial TSE images, Thin slices and small FOV was used to obtain TIRM images and high resolution T2-weighted images, Oblique coronal images were paralel to the anal canal and oblique axial images were perpendicular to the anal canal After administration of IV gadolinium chelate, fat saturated T1-weighted oblique axial and oblique coronal images were obtained. All of the patients have signed informed consent form before the examination. Image Analysis Images were evaluated retrospectively by using Centricity RIS/PACS (Picture Archiving and Communication Systems; GE Healthcare) system. Thicknesses of puborectal muscle, internal-external anal sphincter muscles at the proximal, middle and distal parts of the anal canal, longitudinal muscle, subcutaneous external sphincter, vascular structures of the posterior commissure and transvers Page 5 of 22

6 diameter of anococcygeal raphe were measured on the axial images (Fig. 3 on page 6, Fig. 4 on page 7, Fig. 5 on page 8, Fig. 6 on page 9, Fig. 7 on page 10 ). Anorectal angle, anal canal length, anterior-posterior diameter (depth) of Minor triangle and angle between the anal canal and superficial external sphincter muscle (K and B angles) were measured on the sagital images (Fig. 8 on page 11, Fig. 9 on page 12, Fig. 10 on page 13, Fig. 11 on page 14, Fig. 12 on page 16 ). All of the parameters of each case were measured by two radiologists with consensus. Statistical Analysis Average measurements were compared with "Mann-Whitney test" and correlations were evaluated with "Spearman's test". P<0.05 was accepted as statisticaly relevant. Images for this section: Page 6 of 22

7 Fig. 3: Puborectal muscle thickness Page 7 of 22

8 Fig. 4: Internal and external anal sphincter and longitudinal muscle thickness Page 8 of 22

9 Fig. 5: Distance between bilateral subcutaneous external sphincters Page 9 of 22

10 Fig. 6: Transvers diameter of anococcygeal raphe Page 10 of 22

11 Fig. 7: Vascularity of posterior commissure Page 11 of 22

12 Fig. 8: Anorectal angle Page 12 of 22

13 Fig. 9: Anal canal length Page 13 of 22

14 Fig. 10: Depth of the Minor triangle Page 14 of 22

15 Page 15 of 22

16 Fig. 11: Angle between anal canal and superficial external sphincter (K angle) Page 16 of 22

17 Fig. 12: Angle between anal canal and superficial external sphincter (B angle) Page 17 of 22

18 Results Length of the anal canal and distance between subcutaneous external sphincters is significantly greater in the patient group. For the patient group: There is (+) correlation between distal internal sphincter thickness and longitudinal muscle thickness (r=0.360; p=0.010). There is correlation between K angle (traction angle of the anal canal by the superficial external sphincter to the coccyx) and deep (proximal), superficial (middle) anal sphincter muscle thicknesses (respectively, r=0.631, p=0.001; r=0.525, p=0.007). There is (-) correlation between sphincter thickness and antero-posterior diameter (depth) of Minor triangle (r=-0.279; p=0.047). In all of the cases, there were correlations between the thickness of internal and external sphincters and ages of the patients ( Table 1 on page 18 Table 2 on page 19 ). Mean values and standard deviation of the measurements of the patient and control groups are shown at Table 3 on page 19. Images for this section: Page 18 of 22

19 Table 1: Relation between age and proximal, middle and distal internal sphincter thicknesses Table 2: Relation between age and proximal, middle and distal external sphincter thicknesses Page 19 of 22

20 Table 3: Averages and standard deviations of the measurements of patient and control group Page 20 of 22

21 Conclusion Superficial external anal sphincter gets far away from the anus and moves towards the coccyx. The increase of the traction angle (K angle) of the anal canal by the superficial external sphincter to the coccyx may expand the unsupported part (Minor triangle) of anal canal and may have a role in the pathogenesis of anal fissure. It has been thought that length of the anal canal may have a role in the pathogenesis of anal fissure. In the chronic cases, long-standing inflammatory reactions lead to fibrotic skin extensions at the skin outside of the anal canal called "sentinel pile" or "skin tag". The increase of the gap between the subcutaneous external sphincters may be due to the "skin tag". Personal information Dr. Ay#e Erden Ankara University Medical School, Radiology Department, Ankara, Turkey Dr. Elif Peker Ankara University Medical School, Radiology Department, Ankara, Turkey Zeynep B#y#kl# Gençtürk Ankara University Medical School, Biostatistics Department, Ankara, Turkey #lhan Erden Ankara University Medical School, Radiology Department, Ankara, Turkey References 1. Zaghivan KN, Fleshner P. Anal fissure. Clin Colon Rectal Surg 2011; 24: Page 21 of 22

22 2. Billingham RP, Isler JT, Kimmins MH, Nelson JM, Schweitzer J, Murphy MM. The diagnosis and management of common anorectal disorders. Curr Probl Surg 2004;41: Perry WB, Dykes SL, Buie WD, Rafferty JF. Practice parameters for the management of anal fissures (3rd revision). Dis Colon Rectum 2010;53: Goh V, Halligan S, Kaplan G, Healy JH, Bartram CI. Dynamic MR #maging of the pelvic floor in asymptomatic subjects. AJR 2000;174: Page 22 of 22