Comparison of the diagnostic accuracy of percutaneous fistula contrast-enhanced ultrasound combined with transrectal 360 3-d imaging and conventional transrectal ultrasound in complex anal fistula

The study compared the diagnostic accuracy of percutaneous fistula contrast-enhanced ultrasound (CEUS) combined with 360 degrees 3-D transrectal ultrasound (TRUS) imaging (CEUS + 360 degrees-TRUS) with that of con-ventional transrectal ultrasound in the diagnosis of complex anal fistulas. A total of 156 patients clinically diagnosed with complex anal fistula from January 2020 to December 2021 were studied and randomly divided into an experimental group (n = 82) and a control group (n = 74). Patients in the experimental group were examined by percutaneous fistula CEUS combined with CEUS + 360 degrees-TRUS, while patients in the control group were examined using TRUS. The detection of fistulas (main tract, branch and internal orifice) and the accuracy of Parks classification were compared between the two groups. Recurrences were followed up at 1, 3 and 6 mo after the surgery. A total of 156 patients were included, aged 23-68 y (average: 37.7 +/- 18.2 y). In both groups, the course of disease was < 1 mo in 128 cases, 1-2 mo in 22 cases and > 3 mo in 6 cases. A total of 474 fistulas were confirmed by surgery in the aforementioned patients, including 224 main fistulas, 250 branch pipes and 254 inter-nal orifices. The CEUS + 360 degrees-TRUS group had 96.87%, 90.41% and 90.14% diagnostic accuracy for the main tract, branch and internal orifice, which was statistically significant (p < 0.001) compared with the 85.00%, 70.00% and 72.46% for the TRUS group, respectively. The overall accuracy of Parks classification of anal fistula in the CEUS + 360 degrees-TRUS group was significantly higher than that in the TRUS group (90.24% vs. 78.38%, p < 0.001). After 6 mo of follow-up, the recurrence rate in the CEUS + 360 degrees-TRUS group was 4.87%, and the recur-rence rate in the TRUS group was 18.91%. Percutaneous fistula CEUS combined with transrectal 360 degrees 3-D imag-ing has significantly higher accuracy than conventional TRUS in the diagnosis of complex anal fistula, especially for anal fistula branches, internal openings and Parks classification and is beneficial in reducing post-operative occurrence of complex anal fistulas. (c) 2022 The Author(s). Published by Elsevier Inc. on behalf of World Federation for Ultrasound in Medicine & Biology. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).