Abstract:

Objective    To evaluate the role of three-dimension transrectal ultrasonography in locating the internal opening,  trend of fistulas, pus-filled cavity and occult focus in diagnosing perianal infections.  Methods   127 cases of anal fistula and 48 cases of perianal abscess were examined by three-dimensional endoluminal ultrasonography.  According to the characters of the sonogram and echogram, it located the internal opening, traced the trend of fistulas, and detected the pusfilled cavity′s location and the occult focus. Results    In 151 cases the internal opening was located with an accuracy rate of 86.3%（151/175）； in 90 cases one fistula was located, and in 37 cases two fistulas were located. 55 cases of abscess were examined, including 9 cases of sub-cutaneous abscess, 3 cases of sub-mucosal abscess, 4 cases of mucosa subcutaneous abscess, 16 cases of low intramuscular abscess, 11 cases of high intramuscular abscess, 3 cases of ischial rectal space abscess, and 2 cases of pelvic space abscess. All  the above were confirmed by surgery. Conclusion    Three-dimensional endoluminal ultrasonography in diagnosing perianal infections can accurately locate the internal opening, display the trend of fistulas, and effectually detect the pus-filled cavity′s location and the occult focus. And it can provide essential diagnostic criteria for choosing the clinical therapy method.

Key words: Three-dimensional transrectal ultrasonography; Anal fistula; Perianal abscess; Internal opening