Application of DWI in the Assessment of Perianal Fistulas

Abstract

Application of DWI in the Assessment of Perianal FistulasWe zealously read the article "Nononcologic Applications of Diffusion-Weighted Imaging in the Gastrointestinal System" by Dunn et al. [1], which appeared in the April 2015 issue of the American Journal of Roentgenology. We would like to thank the authors for their elucidatory review on a relatively unplumbed topic. Although it is true that DWI has a predominant role in oncologic scenarios, its nononcologic applications, especially in the evaluation of gastrointestinal and abdominal diseases, are increasing. The authors have indeed comprehensively touched on the nononcologic applications of DWI in the evaluation of the gastrointestinal system, including pancreatic, hepatobiliary, splenic, and bowel pathologies. However, we would like to add to the list of nononcologic applications by highlighting the potential role of DWI in the evaluation of perianal fistulas [2][3][4][5][6][7].DWI provides excellent visualization of the perianal fistulas as high-signal-intensity tracts against the significantly suppressed background signal [2][3][4]. Thanks to the high lesion-to-background contrast, DWI can add to confidence in the diagnosis [2,4]. In 2009, Hori and colleagues [2] studied the role of DWI in diagnosing perianal fistulas. Of the 20 anal fistulas diagnosed, 18 (90%) were detected on T2-weighted images and 19 (95%) were detected on DW images and T2weighted images combined. Although there was no statistically significant difference in the sensitivity of the techniques (for all comparison pairs, p > 0.5), the confidence scores associated with DW images and T2-weighted images combined were significantly greater Downloaded from www.ajronline.org by University of Florida on 10/05/15 from IP address 159.178.22.27.