A STUDY OF MRI IN THE EVALUATION OF PERIANAL FISTULA

Dr. M. Vijayakumari, Dr. Sunil Kumar Pushtey

Abstract


           “More is missed by not looking, than by not knowing ”by Thomas Mc Rae.

Fistula-in-ano form a good majority of treatable benign lesions of the rectum and anal canal. 90% or so of these cases are end results of crypto glandular infections. The vast majority of these infections are acute but significant minority is contributed by chronic, low-grade infections, hence pointing to varying etiology.

             The importance of imaging and treatment of a fistula in ano, is attributed to the complex pelvic floor anatomy and the fistula’s notorious reputation of recurrence despite utmost care taken during and after its surgery.

      Surgery can be extremely demanding, especially if the fistula is complex. The objectives are to eradicate the tract and drain associated sepsis whilst simultaneously preserving continence.

      Over the years, many imaging modalities have been tried, to achieve those objectives. These are conventional fistulography, anal endosonography, computed tomography and most recently, MR fistulography.

      Contrast fistulography is the most traditional radiological technique used to define fistula anatomy. It involves catheterization of the external opening and injection of water soluble contrast media which defines the fistulous tract.

      Anal endosonography (AES), developed at St. Mark’s hospital Northwick Park, Harrow, UK was the first technique to directly visualize the anal sphincter complex in detail. Modern 10 MHz rectal endoprobes are used to identify and study the sphincter complex.

      Computed tomography has also been utilised to evaluate fistula in ano. However its ability to image in axial planes only and poor soft tissue differentiation limits its ability to classify fistulae with sufficient accuracy.

      Magnetic resonance imaging is a recently devised modality to study fistula – in – ano. Imaging is done in axial, coronal and sagittal planes using T1, T2, STIR and FATSAT sequences. Various coils, namely, spine array, body array and special endorectal coils may be used.

      The following study involves detailed evaluation of fistula in ano, its complications and pelvic floor anatomy using MR fistulography.


Keywords


MRI, Anal endosonography (AES),PERIANAL FISTULA

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References


Hallingans.s..imaging fistula in Ano.clinical Radiology,1998;53;85-95

Beets – Tan et al. Preoperative MR imaging of Anal fistulas : Does it help ? Radiology, January 2001; 75-84.

Lilius HG, Investigation of human fetal anal ducts and intermuscular glands and a clinical study of 150 patients. Acta Chirugica Scandinavia. 1968, suppl; 383 : 1-88

Lunnis PJ, Amstrong P ,Barker PG,Reznek RH,Philips PK .MR Imaging of Anal fistula .Lancet 1992;340:394-396.

Lunnis PJ, Barker PG, Sultan AH et al. MRI of fistula in Ano. Diseases of the colonal and rectum. 1994; 37 : 708-718.

Spencer JA, Chapple K, Wilson D, Ward J, Windsor or ACJ, Ambrose NS. Outcome after surgery for perianal fistula : Prediction valve of MR imaging. American Journal of Roentgenology 1998; 171 : 403-406

Karmiris K, Bielen D, Vanbeckevoort D, et al. Long-term monitoring of infliximab therapy for perianal fistulizing Crohn’s disease by using magneticresonance imaging. Clin Gastroenterol Hepatol 2011;9 (2):130– 136.

Van Assche G, Vanbeckevoort D, Bielen D, et al. Magnetic resonance imaging of the effects of infliximab on perianal fistulizing Crohn’s disease. Am J Gastroenterol 2003;98(2):332–339.

Beckingham IJ, Spencer JA, Ward J, Dyke GW, Adams C, Ambrose NS. Prospective evaluation of dynamic contrast enhanced magnetic resonance imaging in the evaluation of fistula in ano.Br J Surg 1996;83(10):1396–1398.

Beckingham IJ, Spencer JA, Ward J, Dyke GW, Adams C, Ambrose NS. Prospective evaluation of dynamic contrast enhanced magnetic resonance imaging in the evaluation of fistula in ano. Br J Surg 1996;83(10):1396–1398.

Sahni VA, Ahmad R, Burling D. Which method is best for imaging of Perianal fistula? Abdomen Imaging 2008;33(1):26–30.

deSouza NM, Puni R, Gilderdale DJ, Bydder GM. Magnetic resonance imaging of the anal sphincter using an internal coil. Magn Reson Q 1995;11(1): 45–56.

. deSouza NM, Gilderdale DJ, Coutts GA, Puni R, Steiner RE. MRI of fistula-in- ano: a comparison of endoanal coil with external phased array coil techniques. J Comput Assist Tomogr 1998;22(3): 357–363.


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