1. MR FISTULOGRAPHY: OUR EXPERIENCE WITH PERCUTANEOUS INSTILLATION OF AQUEOUS JELLY INTO THE TRACTS TO DELINEATE PERIANAL FISTULA
Abstract No : IRIA

2. Perianal fistula
Chronic, potentially disabling, problem – for the patient
Recurrence - common
Inadequate surgery – leading cause of recurrence
Over excision may lead to Anal incontinence
MR Fistulography
Provide adequate anatomical delineation of fistula preoperatively
Aid surgeon to plan the appropriate approach
Reduced risk of recurrence

3. Park’s classification of perianal fistula

4. Pathophysiology- Cryptoglandular concept – 90% of cases
Infection of anal glands and crypts within the intersphincteric plane
Inflammatory blockade of their outlets
Abscess formation
Rupture into the anal canal and skin
Fistula formation
Recurrent infections

5. Role of MRI Better soft tissue anatomy and delineation of tracts
3 dimensional assessment - possible
Accurate lengths, types of tracts, openings, subsidiary tracts can be identified
Endorectal coils and/or body coils – can be used

6. Aim of study
Study the role of Instillation of aqueous jelly into the tracts prior to MR Fistulography

7. Study Design Prospective study – January to September 2014
15 cases included
3 females and 12 males
Age range : years
Average age of cases - 35 years

8. Protocol
External opening of fistula- cannulated with a IV cannula or a hypodermic needle
5-7 ml of aqueous jelly instilled prior to the MRI examination.
Jelly used - 2 percent lignocaine jelly.
Siemens Magnetom Avanto – 1.5 Tesla – MR System for scanning

9. MR Protocol Parameters T2 Axial T2 coronal T2 Axial FS T2 Coronal FS
TR in ms
7070
5930
4400
6810
725
TE in ms 85 90 21
Slice thickness
2 mm
Resolution
320/75
256/70
320/70
No of Averages 2 3

11. T2 weighted coronal image showing a fistulous tract in intersphincteric plane (red solid arrow).
T2 weighted axial image showing a intersphincteric type (red solid arrow) of fistulous tract.

12. Other parameters studied
3 cases showed lateral ramifications.
1 case had Supralevator extension.
2 cases had ischioanal abscesses

13. T2 weighted axial mage showing a anterolateral ramification (red solid arrow).
T2 weighted coronal image showing a collection underneath the left levator ani muscle (red solid arrow).

14. T2 weighted coronal mage showing extrasphincteric tract (blue solid arrow).
T2 weighted coronal mage showing a supralevator extension (blue solid arrow).

15. Discussion – MR Fistulography
Various techniques used for better delineation of anatomy of complex fistulae
Post IV contrast (GAD) MRI
Pickup wall enhancement
Chronic cases – usually do not enhance
No tract distension
Smaller tracts – difficult to identify

16. Other techniques used in the past – MR Fistulography
Distension of tracts using
Normal saline
Diluted GAD
Temporary and inadequate distension
Smaller tracts and internal openings – may not be detected

17. Conclusion
Instillation of aqueous jelly into the tracts prior to MR Fistulography has the following benefits
Viscous
Cheap and readily available
Adequate and persistent distension of tracts
Inherent contrast
Harmless and painless - Safe for use

18. References
Buchanan GN, Williams AB, Bartram CI, Halligan S,  Nicholls RJ, Cohen CR. Potential clinical implications of direction of a trans-sphincteric anal fistula track. Br J Surg , 2003; 90 (10)
Akhtar, M. Fistula in Ano-An Overview.JIMSA. 2012; 25(1): 53-55
Parks AG, Gordon PH, Hardcastle JD. A classification of fistula-in-ano. Br J Surg, 1976;63:1–12.
Manar T Alaat El Essawy. Magnetic Resonance Imaging in Assessment of Anorectal Fistulae and its role in management, J Gastroint Dig Syst 2013, 3:3
Khera PS, Badawi HA, Afifi AH. MRI in perianal fistulae. Indian J Radiol Imaging 2010;20:53-7
Myhr GE, Myrvold HE, Nilsen G, et al. Peri-anal fistulas: use of MR imaging for diagnosis. Radiology 1994;191:545–554.
Dariusz Waniczek, Tomasz Adamczyk, Jerzy Arendt, Ewa Kluczewska, Ewa Kozińska-Marek. Usefulness assessment of preoperative MRI fistulography in patients with perianal fistulas. Pol J Radiol, 2011; 76(4): 40-44