Which method is best for imaging of perianal fistula?

Abstract

MRI is the optimal technique for discriminating complex from simple perianal fistula, although AES is superior to clinical examination, and may be used if MRI availability is restricted.

MRI Enteroclysis and Enterography

“…The surgical physical examination has been considered the "gold standard" (sensitivity 99.8 %) for the identification of perianal fistulas in CD for years [7]. Actually, MRI has an increasingly important role in the evaluation of disease activity in CD and of complicated CD and is actually considered the gold standard and recommended during the initial diagnosis of perianal CD according to the ECCO guidelines; moreover, compared to endoanal ultrasound it is comparable for the evaluation of perianal fistulas and proved to be superior for discriminating between simple and complex disease compared to clinical assessment and anal endosonography [10,[30][31][32][33][34][35].…”

“…In particular, the MRI on the axial and coronal planes allows the identification of the connection between the fistula and the sphincter apparatus, the levator ani muscle and the ischiorectal fossa; images on the sagittal plane are useful in the evaluation of rectovesical and rectovaginal fistulas, and in the evaluation of the presacral disease [11,13].…”

“…For the detection of perianal fistulas of any type, there was a perfect statistical agreement between the initial diagnosis of perianal CD unless there is a need for immediate drainage of sepsis. MRI proved to be accurate in the achievement of an optimal definition of the pelvic anatomy and in the detection and classification of superficial and deep fistulas and their relation to surrounding structures [11][12][13]. Most MRI protocols routinely use intravenous gadolinium contrast-enhanced images for the evaluation of perianal CD, and more recently subtraction techniques have been used as well as dynamic imaging [7,14].…”

MRI of Crohn?s Anoperineal Disease

“…Moreover, surgical management may be altered in up to 40% of patients by the addition of MRI to examination under anesthesia (EUA) [19,20]. In particular, MRI has been shown to be of value to study complex perianal fistulae, being able to detect sepsis outside the anal sphincter and their relationship with the sphincter and levator ani muscle [21]. Besides an accurate morphological evaluation of the perianal space, MRI has been demonstrated to provide information about perianal disease activity, assessing inflammatory changes in fistula tracks in response to treatment with infliximab [22][23][24][25][26].…”

Role of magnetic resonance imaging in evaluation of perianal fistulas

“…18 MR imaging is the optimal technique to distinguish complex from simple perianal fistulas. 19 Characteristic MR imaging findings are obtained for perianal fistulas and abscesses with the different sequences of the protocol. T1-weighted images give an excellent anatomic overview of the sphincter complex, levator plate, and ischiorectal fossa.…”