Nishith Kumar MD, Presenter: Nothing to Disclose

Yatish Agarwal, Abstract Co-Author: Nothing to Disclose

A S Chawla, Abstract Co-Author: Nothing to Disclose

R Chandra, Abstract Co-Author: Nothing to Disclose

Udhaya Kumar Kuppan MBBS, Abstract Co-Author: Nothing to Disclose

Brij Bhushan Thukral, Abstract Co-Author: Nothing to Disclose

To evolve a roadmap for optimal utilization of MR sequences in the imaging of perianal fistulae in relation to their specific characteristics.

The study comprises of 30 subjects with suspected complex and/recurrent perianal fistulae. Each subject was evaluated with DRE and MRI using STIR, SPIR and contrast enhanced sequence using phased array pelvic coil. Position of internal opening, class of fistula and the presence of secondary tracts and/or abscesses were recorded.

Of the 30 subjects, 11 had recurrent perianal fistulae.MRI was found statistically more significant in the detection of internal opening with a sensitivity of 96.67 % as against 33% for DRE. STIR and SPIR sequence detected the internal opening of the fistulae in 28/30 (93.33%). DRE was accurate in classifying the fistulae in 10 (33.33%) subjects. In comparison, post contrast T1weighted sequence was able to do so in 26 (86.67%) cases. The SPIR and STIR sequence could correctly classify the fistulae in 24 (80%) patients. In all, 19 out of the 30 patients were found to have secondary extensions at the time of surgery. DRE was able to detect 8/19 (42.11%), whereas MR imaging could identify 18/19 (94.74%). STIR, SPIR and post contrast T1weighted sequence did equally well. The perianal abscesses and horseshoeing were identified in 8/9 (89%) and 7/11 (64%) cases respectively on DRE. In contrast, all 9 abscess and the 11 horseshoe extensions were detected on each of the three MR sequences with a detection rate of 100%.  

MR examination of the perianal region plays a critical role in the management of complex and recurrent perianal fistulae. Post contrast T1weighted sequence scores over the SPIR and STIR sequence, thus MR Imaging of perianal fistulae is best optimised by obtaining the pre- and post-contrast T1weighted sequence in coronal and axial plane. The SPIR and STIR sequence may be reserved for patients who cannot be administered.  

Postcontrast T1weighted sequence outscores SPIR and STIR in imaging of complex and recurrent perianal fistulae, and accords the best roadmap for the operating surgeon.

Kumar, N, Agarwal, Y, Chawla, A, Chandra, R, Kuppan, U, Thukral, B, Roadmap to MR Imaging of Complex Perianal Fistulae.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12043464.html