Learning objectives
To illustrate MRI findings of perianal fistulas with regard to St James’s University Hospital classification and less commonly encountered entities such as anal canal carcinoma,
hidradenitis suppurativa,
pilonidal sinus tracts,
postoperative changes and ano/rectovaginal fistula.
Background
Anal canal is anatomically defined as the end portion of gastrointestinal tract located between anal verge below and junction between anus and rectum above.
Dentate line is located near to mid-anal canal.
Anal canal musculature is composed of two muscle layers.
Internal sphincter is a smooth muscle which is actually continuation of circular gastrointestinal musculature.
External sphincter is a striated muscle,
controlled voluntarily,
it is the continuation of levator ani muscle.
Anal and perianal pathologies are radiologically best demonstrated with magnetic resonance imaging (MRI) owing...
Findings and procedure details
Perianal fistula
Perianal fistula is usually encountered in young adults [3].
It most commonly presents with discharge [4].
It is more common among men.
Possible underlying pathogenesis of perianal fistulas is proposed to be intersphincteric ductal obstruction with resultant anal gland infection and sepsis,
which is known to be ‘cryptoglandular hypothesis’.
In the first setting infection takes place in the intersphincteric space which is the most common location and presentation for idiopathic fistulas.
Though usually primary in origin,
Crohn’s disease,
pelvic surgery,
tuberculosis and pelvic...
Conclusion
MRI has a crucial role both for detection of anal - perianal pathologies that has a wide differential diagnosis and for detection recurrences or residual pathologies during posttreatment follow-up.
Personal information
Sinan Balci,
Department of Radiology,
Artvin State Hospital,
Artvin/TR
Mehmet Ruhi Onur,
Department of Radiology,
Hacettepe University,
Sıhhiye Ankara/TR
Ali Devrim Karaosmanoglu,
Department of Radiology,
Hacettepe University,
Sıhhiye Ankara/TR
Musturay Karcaaltincaba,
Department of Radiology,
Hacettepe University,
Sıhhiye Ankara/TR
Deniz Akata,
Department of Radiology,
Hacettepe University,
Sıhhiye Ankara/TR
Mustafa N.
Ozmen,
Department of Radiology,
Hacettepe University,
Sıhhiye Ankara/TR
References
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MRI of perianal fistulas: bridging the radiological-surgical divide. Abdom Imaging,
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1033-42.
3.Khati,
N.J.,
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CT of acute perianal abscesses and infected fistulae: a pictorial essay. Emerg Radiol,
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5.Llauger,
J.,
et al.,
The normal and pathologic ischiorectal fossa at CT and MR...