Transcript 171x - Stanley Radiology

Author: Joish Upendra Kumar
Co Authors: Abimanyu S, Satyendra Raghuwanshi, Tukaram Rathod
Institution: Command Hospital Air Force, Bangalore
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
Park’s classification of perianal fistula
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
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
Aim of study
 Study the role of Instillation of aqueous jelly into the
tracts prior to MR Fistulography
Study Design
 Prospective study – January to September 2014
 15 cases included
 3 females and 12 males
 Age range : 25 -54 years
 Average age of cases - 35 years
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
MR Protocol
Parameters
T2 Axial
T2
T2 Axial
T2 Coronal
coronal
FS
FS
T1 Axial
TR in ms
7070
5930
4400
6810
725
TE in ms
85
90
85
90
21
Slice thickness
2 mm
2 mm
2 mm
2 mm
2 mm
Resolution
320/75
256/70
320/70
256/70
320/70
No of Averages
2
2
3
2
2
Types of fistulous tracts
1
10
4
Transsphincteric
Intersphincteric
Extrasphincteric
T2 weighted axial image showing a
intersphincteric type (red solid arrow) of
fistulous tract.
T2 weighted coronal image showing a fistulous
tract in intersphincteric plane (red solid arrow).
Other parameters studied
 3 cases showed lateral ramifications.
 1 case had Supralevator extension.
 2 cases had ischioanal abscesses
T2 weighted coronal image showing a
collection underneath the left levator ani
muscle (red solid arrow).
T2 weighted axial mage showing a
anterolateral ramification (red solid arrow).
T2 weighted coronal mage showing
T2 weighted coronal mage showing a
supralevator extension (blue solid arrow). extrasphincteric tract (blue solid arrow).
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
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
Conclusion
 Instillation of aqueous jelly into the tracts prior to MR Fistulography
has the following benefits
 Semisolid/Jelly in consistency
 Cheap and readily available
 Adequate and persistent distension of tracts
 Harmless and painless - Safe for use
References
1.
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) 1250 -
1255.
2.
Akhtar, M. Fistula in Ano-An Overview.JIMSA. 2012; 25(1): 53-55
3.
Parks AG, Gordon PH, Hardcastle JD. A classification of fistula-in-ano. Br J Surg, 1976;63:1–12.
4.
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
5.
Khera PS, Badawi HA, Afifi AH. MRI in perianal fistulae. Indian J Radiol Imaging 2010;20:53-7
6.
Myhr GE, Myrvold HE, Nilsen G, et al. Peri-anal fistulas: use of MR imaging for diagnosis.
Radiology 1994;191:545–554.
7.
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