الفهرس 
PathologyOnly 14 pages are availabe for public view
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Abstract
MRI has become the method of choice for evaluating the perianal fistula due to its good contrast resolution, simple, non invasive, rapid and accurate technique.MRI is especially important in patients with crohn’s disease and recurrent fistulae. As those entities accompanied by secondary extensions, abscesses and branching fistulae.MRI provides precise definition of the fistulous tract along with its relationship to the pelvic structures. MRI provides accurate information for appropriate surgical management in order to prevent recurrence and decrease the side effects such as fecal incontinence.
from our study that T2WI (TSE and fat suppressed) is the most important sequence for detection of the fistulous tract with the good contrast between the hyper-intense fluid in the tract and the hypo-intense wall of the tract, providing good delineation of the anal sphincter. Especially the coronal plane.
For the exact location of the primary tract we use the axial plane, the disruption of the external anal sphincter differentiate intersphincteric type from transsphincteric type. The site of internal opening also detected from this plane.
The coronal plane depicts the levator plane thus differentiating supralevator from infralevator infectionA combination of an axial and a longitudinal series (coronal, sagittal or radial) will provide all the necessary details.
Gadolinium based T1WI differentiate fluid filled tract from an area of inflammation. The tract wall enhance while the central portion is hypo-intense. Abscesses show avid contrast enhancement.
According to MR findings and based on Park’s classification[46] the fistulae were classified into the following types; intersphincteric(If a fistula remains contained by the external sphincter throughout its course) transsphincteric(when internal opening is anal and fistula pierces both layers of the sphincter complex reaching the skin through the ischiorectal fossa) suprasphincteric (fistula penetrate the pelvic floor above the level of the puborectalis and internal opening is anal) and extrasphincteric (fistula penetrate the pelvic floor above the level of the puborectal is and internal opening is rectal.
According to MRI findings and ST Jame’s university hospital[2]:This classification consider the primary tract as well as the secondary extensions and abscess formation we found four types: Grade I:Simple linear intersphincteric, Grade II:Intersphincteric with an abscess or secondary tract .Grade III:Transsphincteric,Grade IV:transsphincteric with secondary tract or abscess in ischiorectal or ischioanal fossa .Grade V:Supralevator or translevator.