Pelvic CT as a First-line Imaging Tool for Diagnosis of Perianal Abscess: A Single-center Retrospective Study

BACKGROUND Pelvic CT is a safe, accurate, economical, and effective tool for preoperative imaging diagnosis. However, the clinical value of pelvic CT in the preoperative diagnosis of perianal abscess remains to be further assessed. METHODS In this retrospective study, we analyzed data from patients with perianal abscesses treated in our hospital's department of anorectal department from March 1, 2023, to June 30, 2023. All patients were examined by pelvic CT before the operation, and the type, location, and internal opening of the perianal abscess were recorded intraoperatively. Taking the actual results observed during the operation as the reference standard, the differences between the diagnosis results of pelvic CT and the actual results during the operation were compared, and the diagnostic value of pelvic CT before perianal abscess surgery was analyzed. RESULTS Finally, 33 patients were included, and the actual intraoperative results were ①type of perianal abscess: 19 cases were deep abscess and 14 cases were superficial abscess.②Location of perianal abscess (lithotomy position): 7 were located in the left anterior, 2 in the right anterior, 8 in the left posterior, 4 in the right posterior, 2 in the anterior center, 8 in the posterior center, 1 in the left center, and 1 in the right center. ③The internal opening of perianal abscess: 8 were at 0-3 o'clock position (including 3 o'clock position), 20 cases were at 3-6 o'clock position (including 6 o'clock position), 4 cases were at 6-9 o'clock position (including 9 o'clock position), 1 cases were at 9-12o'clock position (including 12 o'clock position). Pelvic CT diagnostic accuracy: ①type of perianal abscess: 19 cases of deep abscess, 19 cases were consistent with the reality; for 14 cases of superficial abscess, 14 cases were consistent with the actual, and the accuracy was 100%. ②Regarding the location of the perianal abscess, 31 of the 33 cases were consistent with reality, with an accuracy of 93.94%. For the internal opening of the perianal abscess, 27 of the 33 cases were consistent with reality, with an accuracy of 81.82%. CONCLUSIONS Pelvic CT can conveniently, quickly, and accurately determine the perianal abscess type, location, and internal opening. Compared with other imaging tools such as perianal ultrasound and MRI, pelvic CT has apparent advantages, such as being painless, fast, and economical, and is expected to become a first-line imaging tool for preoperative diagnosis of perianal abscess. We look forward to more large-sample, multicenter, high-quality clinical studies to confirm this conclusion and prepare for its entry into the guidelines for diagnosing and treating perianal abscesses.