Magnetic Resonance Imaging and Peroxide-Enhanced Anal Endosonography in Assessment of Fistula in Anus: Comparison With Surgery Publisher



Ghafoori M¹ ; Mahjoubi B² ; Youseffam H² ; Mollabashi M³ ; Nikbakht H⁴
Source: European Surgery - Acta Chirurgica Austriaca Published:2016

Abstract

Background: Although there are numerous modalities to evaluate perianal fistula, there is still a need to determine the most sensitive, specific, and accurate modality. This study was conducted to determine the performance characteristics of magnetic resonance imaging (MRI) and contrast-enhanced three-dimensional endoanal ultrasonography (C-3DEAUS) considering surgery as the gold standard. Methods: A total of 36 patients who were diagnosed of having anal fistula with 10-MHz hydrogen peroxide-enhanced three-dimensional EAUS underwent MRI followed by surgery. Both of tests were done the day before surgery. Fistula classification was determined with each modality according to Parks’ criteria as inter-sphincteric, trans-sphincteric, extra-sphincteric, or supra-sphincteric and was compared with the surgical findings in all patients. If the accuracy of each modality was at least 85 % compared with the surgery, it was considered as clinically useful. Results: Agreement for the classification of the primary fistula tract was 94.3 % for C-3DEAUS and surgery, 97.1 % for MRI and surgery. Considering a clock face, C-3DEAUS and surgery agreed in location of internal opening in 88.6 % of cases while MRI and surgery agreed in 97.1 %. In detection a collection, agreement between C-3DEAUS and surgery was 82.9 %, and 97.1 % between MRI and surgery. Conclusions: Both methods had almost perfect agreement with surgical findings in the classification of the primary fistula tract but MRI had more agreement in distinguishing other aspects of a fistula and it can be used as the most reliable method for preoperative evaluation of perianal fistulas. © 2015, Springer-Verlag Wien.