Value of Hydrogen Peroxide Enhancement of Three-Dimensional Endoanal Ultrasound in Fistula-in-Ano

Abstract

In recurrent or complex fistula-in-ano, endoanal ultrasound proved more accurate for detecting primary tracks and internal openings than for detecting extensions. Hydrogen peroxide improved conspicuity of some tracks and internal openings and so may be helpful in difficult cases, although no overall diagnostic benefit was demonstrated.

Three-dimensional endoanal ultrasonographic assessment of an anal fistula with and without H2O2enhancement

“…In the present study, the agreement of 3D-EAUS with surgery was excellent: 84% in the detection of primary tracts, 84% in internal openings, and 82% in secondary extensions. These outcomes are consistent with recent data concerning 3D-EAUS [16][17][18] . Most reports using conventional 2D-EAUS have shown superior results with H2O2 enhancement.…”

“…Another point to consider is that although H2O2 enhancement had little influence on diagnostic accuracy improvement, H2O2 enhancement often improved the quality of images in cases where the unenhanced study barely delineated the tract as shown in Figure 1 of this study and in another report [17] . The presence of gas in the internal opening or fistula track made the tract more obvious.…”

“…Ratto et al [16] obtained improved diagnostic accuracy by using H2O2, and West et al [5] reported high diagnostic accuracy with H2O2 enhanced 3D-EAUS, comparable to MRI. However, the improved accuracy was not apparent in the study of Buchanan et al [17] . We identified a few more primary tracts and secondary extensions by using H2O2.…”

“…In this regard, contrasting with H2O2 could be more useful in patients with recurrent fistulae, which usually accompany previous operative scars. Several authors have suggested that H2O2 might be more helpful in recurrent cases [8,17] . The number of recurrent or Crohn's disease cases in this study was relatively low.…”

Imaging Classification of Perianal Fistula Using the Ultrasound

“…Optimizing the combined ultrasound approaches, we can inject saline with little air or dilute hydrogen peroxide into the fistula track which helps to discover the site of internal opening by detecting gas bubble emerging from its site and to detect multiplicity of internal opening [15] . Adding to the advantages of the technique is the real time imaging of saline mixed with air bubbles or hydrogen peroxide flowing inside the track, which helps to detect obstructed tracks that may contribute to false passage during probing.…”