Application of contrast-enhanced ultrasound in preoperative diagnosis of anal fistula

Abstract

Objective To evaluate the clinical value of contrast-enhanced ultrasound (CEUS) in preoperative diagnosis of anal fistula. Methods Forty-five patients with fistula in ano were evaluated by physical examination, then CEUS were peformed by injecting SonoVue through the external opening to enhance the detection of the fistulous track and the internal opening. The results of CEUS were matched with surgical features to establish their accuracy in preoperative assessment of anal fistula. Results Simple typing fistula was found in 19 of 45 patients and 26 patients had complex fistulas. The accurate diagnostic rates by conventional ultrasound of simple typing fistula and complex fistulas were 89. 5% and 61.5%,respectively,the accurate diagnostic rates by CEUS of simple typing fistula and complex fistulas were 94. 7% and 92.3%, respectively, there was no significant difference between conventional ultrasound and CEUS about simple typing fistula( P ＞0.05), and there was significant difference about complex fistulas ( P ＜0. 05). Conclusions CEUS has a good visibility and accurate rate for diagnosis of anal fistula,It plays an important role for operation. Key words: Ultrasonography; Microbubbles; Rectal fistular