[Comparison of two-dimensional ultrasound and three-dimensional endoanal ultrasound in the diagnosis of perianal fistula].

OBJECTIVE

To compare the accuracy of two-dimensional endoanal ultrasound (2D-EAUS) and three-dimensional endoanal ultrasound (3D-EAUS) in the diagnosis of perianal fistulas.

METHODS

Image data of 47 perianal fistula patients undergoing surgery in our department between January 2012 and December 2012 were collected. All the patients underwent 2D-EAUS and 3D-EAUS, and the results were compared to intraoperative findings (gold standard) by kappa concordance test.

RESULTS

Both 2D-EAUS and 3D-EAUS showed good concordance with intraoperative findings in internal opening (kappa: 0.776 vs. 0.636). 3D-EAUS had better concordance with intraoperative finding in the diagnosis of intersphincteric, high transsphincteric and suprasphincteric fistulas as compared to 2D-EAUS (kappa: 0.810 vs. 0.592, kappa: 0.863 vs. 0.548, kappa: 1.000 vs. 0.672). 3D-EAUS showed better concordance with intraoperative findings in secondary tract compared to 2D-EAUS(kappa: 0.659 vs. 0.535). Both 2D-EAUS and 3D-EAUS had good concordance with intraoperative findings in complicated abscesses (kappa: 0.881 vs. 0.816).

CONCLUSION

3D-EAUS can show the relationship of fistula with anal sphincter, especially in diagnosing high fistula and fistula with secondary tracts, and has a higher diagnostic accuracy than 2D-EAUS.