imaging anal fistulae
DESCRIPTION
anal fistulaTRANSCRIPT
![Page 1: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/1.jpg)
Imaging of Anal Fistula
Dr Sue Roach
![Page 2: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/2.jpg)
Introduction
Pre-operative confirmation of fistula complexity has been shown to facilitate surgical planning of sphincter saving techniques[1] and to reduce the incidence of unidentified sepsis, which is the leading cause of fistula recurrence [2].
![Page 3: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/3.jpg)
Imaging Objectives
• Determine relationship of fistula to sphincter complex
• Identify any secondary fistulous tracks
![Page 4: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/4.jpg)
Imaging Modalities
• Fistulography
• Endoanal ultrasound
• Magnetic resonance
![Page 5: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/5.jpg)
Fistulography
• Acute tracks may not have a patent lumen
• Difficult to relate the track to the sphincter and levator ani
• Shown to be accurate in only 16% [3]
• Helpful for chronic fistulae with an external opening distant from the anus
![Page 6: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/6.jpg)
Endoanal ultrasound
• Operator dependent• Highly accurate at identifying the internal
opening [4]
• Depicts fewer secondary extensions than MR
• Difficulty differentiating active track from fibrosis
![Page 7: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/7.jpg)
Magnetic Resonance
• Most accurate technique for evaluation of the primary track and any extensions [4].
• More accurate predictor of patient outcome than surgical findings at EUA[5].
![Page 8: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/8.jpg)
Beets-Tan RGH, Beets GL, Gerritsen van der Hoop A. et al. Preoperative MR Imaging of Anal Fistulas: Does it Really Help the Surgeon?
Radiology 2001; 218:75-84
• Prospective study 56 patients
• MR prior to surgery but result witheld from surgeon until end of surgery while patient still anaesthetised
• Important additional information in 21%. Benefit greatest in crohns (40%), recurrent fistulas (24%), primary fistulas (8%)
![Page 9: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/9.jpg)
Spencer JA, Chapple K, Wilson D et al. Outcome After Surgery for Perianal Fistula: Predictive Value of MR Imaging. AJR 1998; 171:403-406
• Prospective study 48 patients• MR and then surgical exploration blinded to MR• MR categorised 41% complex. Surgery 38%.
Only agreed in 8 cases• 19 patients required further surgery. 13 of these
considered complex on MR, 9 by surgery• MR better at predicting outcome than surgery
![Page 10: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/10.jpg)
Gadolinium?
• Post operative problems
• Complex cases such as crohns disease[6]
![Page 11: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/11.jpg)
Endoanal coil?
• Endocoils give superior anatomical resolution of fistula disease within the sphincter
• Resolution falls off rapidly outside the sphincter
• Complex tracks outside the sphincter are not well seen
![Page 12: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/12.jpg)
![Page 13: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/13.jpg)
![Page 14: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/14.jpg)
![Page 15: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/15.jpg)
MR Technique
• Phased array pelvic coil
• Axial and coronal imaging of the perineum
• T1 and short T1 inversion recovery (STIR) images obtained
• Additional saggital high resolution T2 images occasionally helpful
• IV gadolinium rarely administered
![Page 16: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/16.jpg)
![Page 17: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/17.jpg)
![Page 18: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/18.jpg)
![Page 19: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/19.jpg)
Morris J, Spencer JA, Ambrose S. MR Imaging Classification of Perianal Fistulas and Its implications for Patient Management. Radiographics 2000; 20:623-635
![Page 20: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/20.jpg)
Grade 1 Simple Intersphincteric Fistula
![Page 21: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/21.jpg)
Grade 2 Intersphincteric track with secondary track or abscess
![Page 22: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/22.jpg)
Grade 3 Trans-sphincteric Fistula
![Page 23: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/23.jpg)
Grade 4 Trans-sphincteric Fistula With Abscess or Secondary
Track
![Page 24: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/24.jpg)
Grade 5 Supralevator and Translevator Disease
![Page 25: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/25.jpg)
Aims
• To establish the common MR patterns of idiopathic peri-anal fistulation in Hope Hospital patients.
![Page 26: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/26.jpg)
Methods
• Retrospective review
• 24 consecutive MR scans performed for idiopathic anal fistulation
• Scans performed on a 1 Tesla MR scanner with phased array pelvic coil technique
![Page 27: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/27.jpg)
Results13
29
421
25
8
Grade 0Grade 1Grade 2Grade 3Grade 4Grade 5
% of patients
![Page 28: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/28.jpg)
Discussion
• Majority (50%) of patients with idiopathic peri-anal fistulation have uncomplicated disease
• 25% have trans-sphincteric fistulae complicated by secondary tracks or ischiorectal abscess
• Supra-levator or trans-levator disease is relatively rare in this patient group (8%).
![Page 29: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/29.jpg)
Grade 1- Intersphincteric fistula
![Page 30: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/30.jpg)
![Page 31: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/31.jpg)
![Page 32: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/32.jpg)
![Page 33: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/33.jpg)
![Page 34: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/34.jpg)
![Page 35: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/35.jpg)
![Page 36: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/36.jpg)
![Page 37: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/37.jpg)
![Page 38: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/38.jpg)
Grade 2- Intersphincteric fistula with collection
![Page 39: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/39.jpg)
![Page 40: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/40.jpg)
Grade 3- Trans-sphincteric fistula
![Page 41: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/41.jpg)
![Page 42: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/42.jpg)
![Page 43: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/43.jpg)
![Page 44: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/44.jpg)
![Page 45: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/45.jpg)
![Page 46: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/46.jpg)
![Page 47: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/47.jpg)
![Page 48: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/48.jpg)
![Page 49: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/49.jpg)
![Page 50: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/50.jpg)
![Page 51: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/51.jpg)
![Page 52: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/52.jpg)
![Page 53: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/53.jpg)
![Page 54: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/54.jpg)
![Page 55: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/55.jpg)
![Page 56: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/56.jpg)
![Page 57: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/57.jpg)
![Page 58: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/58.jpg)
![Page 59: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/59.jpg)
![Page 60: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/60.jpg)
![Page 61: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/61.jpg)
![Page 62: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/62.jpg)
![Page 63: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/63.jpg)
![Page 64: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/64.jpg)
![Page 65: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/65.jpg)
![Page 66: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/66.jpg)
![Page 67: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/67.jpg)
![Page 68: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/68.jpg)
![Page 69: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/69.jpg)
![Page 70: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/70.jpg)
![Page 71: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/71.jpg)
![Page 72: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/72.jpg)
![Page 73: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/73.jpg)
![Page 74: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/74.jpg)
![Page 75: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/75.jpg)
![Page 76: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/76.jpg)
Grade 4- Trans-sphincteric fistula with secondary track
![Page 77: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/77.jpg)
![Page 78: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/78.jpg)
![Page 79: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/79.jpg)
![Page 80: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/80.jpg)
![Page 81: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/81.jpg)
Grade 5- Translevator disease
![Page 82: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/82.jpg)
![Page 83: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/83.jpg)
![Page 84: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/84.jpg)
![Page 85: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/85.jpg)
![Page 86: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/86.jpg)
Summary
• MR is a valuable modality in the assessment of peri-anal fistula
• Accurately identifies disease complexity
![Page 87: Imaging Anal Fistulae](https://reader035.vdocuments.site/reader035/viewer/2022062216/563dbb19550346aa9aaa400e/html5/thumbnails/87.jpg)
References
• 1: Beets-Tan RGH, Beets GL, Gerritsen van der Hoop A. et al. Preoperative MR Imaging of Anal Fistulas: Does it Really Help the Surgeon? Radiology 2001; 218:75-84
• 2: Bartram C, Buchanan G. Imaging anal fistula. Radiol Clin N Am 41 (2003) 443-457
• 3: Kuijpers HC, Schulpern T. Fistulography for fistula-in-ano: is it useful? Dis Colon Rectum 1985;28:103-4
• 4: Buchanan GN, Halligan S, Bartram CI et al. Clinical Examination, Endosonography, and MR Imaging in Preoperative Assessment of Fistula in Ano: Comparison with Outcome-based Reference Standard. Radiology 2004; 233:674-681
• 5: Spencer JA, Chapple K, Wilson D et al. Outcome After Surgery for Perianal Fistula: Predictive Value of MR Imaging. AJR 1998; 171:403-406
• 6: Horsthius K, Stoker J. MRI of perianal crohn’s disease. AJR 2004; 183:1309-1315
• 7: Morris J, Spencer JA, Ambrose S. MR Imaging Classification of Perianal Fistulas and Its implications for Patient Management. Radiographics 2000; 20:623-635