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

Pelvic CT as a First-line Imaging Tool for Diagnosis of Perianal Abscess: A Single-center Retrospective Study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Pelvic CT as a First-line Imaging Tool for Diagnosis of Perianal Abscess: A Single-center Retrospective Study Jun Li, Jiaqi Wei, Yujiao Wu, Weizheng Huang, Xiangdong Yang, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4621204/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract 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. Health sciences/Medical research Health sciences/Signs and symptoms Figures Figure 1 Introduction Perianal abscess is an acute suppurative infection that occurs in the soft tissue or space around the anus and rectum. 1 According to the location, a perianal abscess can be divided into two types: deep and superficial. 2 The perianal symptoms of patients with deep perianal abscess are not severe, mainly manifested as anal distension, sense of defecation, local skin temperature rise, and even accompanied by fever and other systemic symptoms; at this time the finger examination of rectal wall bulge, tenderness is apparent, fluctuation is also more apparent. 3 The patients with superficial perianal abscesses mainly showed redness, swelling, fever, pain, and other symptoms. At this time, there was a hard mass around the anus, and there was apparent fluctuation when the abscess matured. 4 According to research, the incidence of perianal abscess in China is 0.16%-0.24%, while that in the United States is as high as 0.5%-1.0%. 5 With the development of society and the change in people's dietary structure, the prevalence rate of perianal abscess increased obviously. 6 The diagnosis is relatively easy because of the prominent clinical symptoms and signs of perianal abscess. The disease is progressing rapidly, and the first-line treatment recommended by the American Association of Colorectal Surgeons Clinical practice guidelines and the Chinese Clinical diagnosis and treatment of Perianal abscess (2018 version) are timely incision and drainage (surgical drainage) and antibiotic treatment.Once incision and drainage are delayed, perianal abscesses are likely to continue to spread to deep and surrounding tissues or even develop into widespread systemic infections and life-threatening, such as pelvic abscesses, septic shock, sepsis, and necrotizing fasciitis, with mortality rates of 20%, 30%, 20%, 50%, and 80%, respectively. 7 To make timely and accurate incision and drainage for patients, it is essential to quickly and accurately determine the type, location, and internal opening of perianal abscess before operation, which can significantly reduce tissue injury and effectively protect anal function to improve the cure rate. 8 Physical examination can reveal symptoms such as redness, swelling, heat, and pain. In contrast, imaging examinations such as ultrasound, MRI, and CT have been shown in clinical practice to provide doctors with accurate diagnostic information to help guide surgery. 9 Therefore, anal examination and perianal ultrasound are commonly used to determine the location and internal opening of perianal abscesses in St. Mark's Hospital in the United Kingdom and Sloan-Catelyn Cancer Center in the United States. In contrast, anal examination, perianal ultrasound, or MRI are commonly used in Peking Union Medical College Hospital in China to determine the location and internal opening of the perianal abscess. Perianal ultrasound can clearly show the location and size of perianal abscesses and the anatomical structure of adjacent tissues and can guide the drainage of abscesses or aspiration of pus. 10 However, the ability to locate and evaluate deep abscesses or complex abscesses is limited. The research of Gkegkes et al. also confirmed this point. (Gkegkes ID, Stamatiadis AP, et al. Anal Pain of an Unusual Cause: Role of Endoanal Ultrasound. J Med Ultrasound 2019, 27: 107-109.) MRI has good soft tissue contrast, can clearly show the structural characteristics of perianal abscess, and low radiation dose to patients. However, there are limitations in patients who are intolerant to confined spaces or have metallic foreign bodies. The examination cost is high, and the time is long, so it is unsuitable for diseases with rapid progression, such as perianal abscess. 11 Accurate and rapid preoperative imaging diagnosis is of great practical significance for clinicians to determine the best surgical plan according to the progressive characteristics of the perianal abscess. Some studies have found that pelvic CT can provide comprehensive perianal and pelvic anatomical information, better locate and evaluate deep or complex perianal abscesses, and even detect other potential pelvic lesions. 12 Compared with MRI and perianal ultrasound, CT takes less time, which is very helpful for preoperative evaluation and operation planning of perianal abscess. 13 Given this, the research group tried to prospectively use pelvic CT as an imaging diagnostic tool to guide anorectal surgeons to perform surgery before perianal abscess surgery. To clarify the preoperative diagnostic value of pelvic CT in perianal abscess, the authors conducted a retrospective study of patients with perianal abscess treated in our hospital from March 1, 2023, to June 30, 2023. By comparing the diagnostic results of pelvic CT and intraoperative observation, the diagnostic accuracy of pelvic CT in the type, location, and internal orifice of perianal abscess was obtained, and the diagnostic value of pelvic CT in perianal abscess was discussed by indirect comparison. Thus, it provides evidence-based basis for pelvic CT as a first-line preoperative imaging diagnostic tool for perianal abscess to enter the guide for diagnosis and treatment of perianal abscess. Methods PARTICIPANTS Patients with perianal abscesses treated in the anorectal department affiliated with the Hospital of Southwest Medical University from March 1, 2023, to June 30, 2023.Approval was waived for this due to its retrospective nature. Informed consent was waived for this due to its retrospective nature.All methods were carried out in accordance with relevant guidelines and regulations. INCLUSION AND EXCLUSION CRITERIA Inclusion criteria: complete medical history information of patients with perianal abscess; Have surgical indications and undergo surgery; pelvic CT examination before operation (if the patient is a pregnant woman, pelvic CT examination is not recommended). Exclusion criteria: No pelvic CT examination was performed before the operation. The lowest scanning part of pelvic CT is higher than the ischial tubercle, which affects regular reading. CT ASSESSMENT The radiation technologist of the affiliated Hospital of Southwest Medical University collected the results of pelvic CT examination with a 64-slice CT scanner (Erlangen Siemens Health Company, Germany). The patients were supine (legs extended and fixed on pedals). Scan parameters: 120kVp tube voltage, and use automatic exposure control to adjust the tube current according to the patient's size and body weight. The collimation is 0.6mm × 64, the rotation time is 0.8s, the pitch is 1.0750, and the FOV is 300.0mm. All images were reconstructed with standard soft tissue nucleus, slice thickness was 3mm, and 2mm was thickened. Pelvic CT was read by experienced anorectal surgeons and radiologists, focusing on the sphincter signal: the position of the perianal abscess was judged according to the anal coccyx ligament (lithotomy position, Figure 1 ). When necessary, combined with the inversion signal MPR (multiplanar reconstruction), a report (including at least the type, location, and internal opening of perianal abscess) was generated from multiple angles of cross-section, sagittal plane, and coronal plane. SURGICAL TREATMENT Fixed anorectal surgeons performed surgery according to pelvic CT diagnosis report and intraoperative exploration: One-time incision and drainage of perianal abscess, including internal opening treatment, were performed for a perianal abscess with the definite internal opening, while simple incision and drainage were performed for a perianal abscess with the unclear internal opening. Suppose it is found that the diagnosis of pelvic CT is not consistent with the actual situation of intraoperative exploration. In that case, the corresponding plan should be made according to the patient's actual situation and the operator's clinical experience. Special personnel recorded the operation process in detail, including the type, location, and internal opening of the perianal abscess. DATA COLLECTION The research group obtained data from patient medical records, including basic information about patients, surgical records, pelvic CT diagnosis reports, and so on. Surgical records were used as the gold standard to judge whether the pelvic CT diagnosis was accurate. STATISTICAL ANALYSIS The statistical software SPSS26.0 and the WPS Office version 11 system were used for data processing and analysis. Counting data is expressed as a numerical value or percentage (%), and Continuous variables are expressed as mean ±standard deviation. χ 2 test was used for classified variables, and the t-test was used for continuous variables. P < 0.05 was considered statistically significant to evaluate the difference between groups. Results GENERAL CLINCAL DATA OF THE PATIENTS A total of 176 cases of perianal abscess were obtained in this study. After careful exclusion, 33 patients were included in the study, including 30 males (91%) and 3 females (9%), with an average age of 47.13 ±14.35 (20-81 years) and an average weight of 54.59 ±13.84kg. The average course of the disease was 4 days, the shortest was 1 day, and the longest was 13 days. The severity of the disease varied, including 15 (45%) mild, 11 (33%) moderate, and 7 (21%) severe. THE ACTUAL SITUATION OBSERVED DURING THE OPERATION According to intraoperative exploration, anorectal surgeons found that there were 33 cases of perianal abscesses, including 19 cases of deep abscesses and 14 cases of superficial abscesses. Location of perianal abscess: Of the 33 patients, 7 (21%) were located in the anterior left, 2 (6%) in the anterior right, 8 (24%) in the right posterior, 4 (12%) in the right posterior, 2 (6%) in the anterior center, 8 (24%) in the posterior center, 1 (3%) in the left center, and 1 (3%) in the right center. The internal opening of perianal abscess: Of the 33 patients, 8 (24%) were at 0-3 o'clock (including 3 o'clock), 20 (61%) at 3-6 o'clock (including 6 o'clock), 4 (12%) at 6-9 o'clock (including 9 o'clock), 1 (3%) at 9-12o'clock (including 12 o'clock), as detailed in Table 1. Table 1. Actual Results Observed During Operation * Patients, No. Types of perianal abscesses Locations of Perianal abscess Internal opening 1 A left anterior 6 o 'clock 2 B front center 7 o 'clock 3 B left anterior 1 o 'clock 4 B left anterior 1 o 'clock 5 B front center 2 o 'clock 6 A back center 6 o 'clock 7 B left anterior 1 o 'clock 8 B left posterior 4 o 'clock 9 A back center 6 o 'clock 10 A left posterior 11 o 'clock 11 A right posterior 6 o 'clock 12 B back center 5-6 o 'clock 13 A right anterior 4 o 'clock 14 B left anterior 1 o 'clock 15 A left posterior 5 o 'clock 16 A back center 6 o 'clock 17 B left anterior 2 o 'clock 18 A left posterior 5 o 'clock 19 A left center 6 o 'clock 20 A back center 5-6 o 'clock 21 B right posterior 7 o 'clock 22 A back center 2 o 'clock 23 A left anterior 6 o 'clock 24 A left posterior 5-6 o 'clock 25 B right posterior 2-3 o 'clock 26 B right anterior 9 o 'clock 27 A left posterior 4-6 o 'clock 28 A left posterior 6 o 'clock 29 A back center 6 o 'clock 30 B right posterior 4-5 o 'clock 31 A left posterior 6 o 'clock 32 B back center 9 o 'clock 33 A right center 6 o 'clock *Note: A =deep abscess， B =superficial abscess DIAGNOSTIC RESULTS OF PELVIC CT SCAN According to the diagnosis report of pelvic CT scan before operation, it was found that there were 33 cases of perianal abscess, including 19 cases of deep abscess and 14 cases of superficial abscess. Location of perianal abscess: Of the 33 patients, 6 (18%) were located in the anterior left, 3 (8%) in the anterior right, 7 (21%) in the left posterior, 5 (15%) in the right posterior, 2 (6%) in the anterior center, 8 (24%) in the posterior center, 1 (3%) in the left center and 1 (3%) in the right center.Internal opening of perianal abscess: Among the 33 patients, 11 (33%) were at 0-3 o'clock position (including 3 o'clock position), 18 (55%) cases were at 3-6 o'clock position (including 6 o'clock position), 2 (6%) cases were at 6-9 o'clock position (including 9 o'clock position), 2 (6%) cases were at 9-12 o'clock position (including 12 o'clock), details are shown in Table 2 . Table 2. Diagnosis of Pelvic CT Scan * Patients, No. Types of perianal abscesses Locations of Perianal abscess Internal opening 1 A left anterior 6 o 'clock 2 B front center 2 o 'clock 4 B left anterior 1 o 'clock 5 B front center 1 o 'clock 6 A back center 6 o 'clock 7 B left anterior 1 o 'clock 8 B left posterior 4 o 'clock 9 A back center 6 o 'clock 10 A left posterior 11 o 'clock 11 A right posterior 3 o 'clock 12 B back center 5-6 o 'clock 13 A right anterior 4 o 'clock 14 B left anterior 1 o 'clock 15 A left posterior 5 o 'clock 16 A back center 6 o 'clock 17 B left anterior 3 o 'clock 18 A left posterior 5 o 'clock 19 A left center 6 o 'clock 20 A back center 5-6 o 'clock 21 B right posterior 7 o 'clock 22 A back center 2 o 'clock 23 A right anterior 1 o 'clock 24 A left posterior 5-6 o 'clock 25 B right posterior 2-3 o 'clock Table 2. (Continued.) * Patients, No. Types of perianal abscesses Locations of Perianal abscess Internal opening 26 B right anterior 9 o 'clock 27 A left posterior 4-6 o 'clock 28 A left posterior 6 o 'clock 29 A back center 6 o 'clock 30 B right posterior 4-5 o 'clock 31 A right posterior 6 o 'clock 32 B back center 11 o 'clock 33 A right center. 6 o 'clock * Note: A =deep abscess， B =superficial abscess DIAGNOSTIC ACCURACY OF PELVIC CT Taking the actual results observed during the operation as the reference standard, the differences between the diagnostic results of pelvic CT and the actual results observed during the operation were compared. Type of perianal abscess: compared with the actual intraoperative results, the accuracy of pelvic CT scanning of deep abscess and superficial abscess was 100%. Location of perianal abscess: compared with the actual intraoperative results, 31 of the 33 patients were diagnosed correctly, with an accuracy of 93.94%. The internal opening of perianal abscess: compared with the actual intraoperative results, 27 of the 33 patients were diagnosed correctly, with an accuracy of 81.82%. Details are shown in Table 3-5 . Table 3. Accuracy of Pelvic CT in the Diagnosis of Perianal Abscess Type (n,%) Variables surgical records(n) Correct pelvic CT(n) Accuracy(%) deep abscess 19 19 100 superficial abscess 14 14 100 Table 4. Accuracy of Pelvic CT for the Location of Perianal Abscess (n,%) Variables Surgical records(n) Correct pelvic CT(n) Accuracy(%) left anterior 7 6 right anterior 2 2 left posterior 8 7 right posterior 4 4 front center 2 2 back center 8 8 left center 1 1 right center 1 1 Total 33 31 93.94 Table 5. Accuracy of Pelvic CT for Diagnosis of Internal Opening (n,%) Variables Surgical records(n) Correct pelvic CT(n) Accuracy(%) 0-3 o 'clock position 8 6 3-6 o 'clock position 20 18 6-9 o 'clock position 4 2 9-12 o 'clock position 1 1 Total 33 27 81.82 Discussion Perianal abscess is a widespread disease, and the incidence rate is as high as 10% -20% in some high-risk groups such as anal foreign body, anal fissure, rectal fistula, and other patients. 14 In addition, people who are sedentary or have limited movement, such as office workers and long-term bedridden patients, are also more likely to develop perianal abscesses. 15 Early, small perianal abscesses can be relieved and cured by non-operative programs (such as drug treatment, hot compress, etc.). If recurrence occurs after non-operative treatment, or the abscess persists, or the abscess spreads to surrounding tissue causing perianal infection or affecting sphincter function, or there are other complications such as anal fistula, surgery should be performed immediately. 16 Surgery can effectively drain and remove infection, thus quickly eliminating inflammation and abscesses and reducing symptoms such as pain and discomfort. 17 The time from the early stage of perianal abscess to the need for surgical treatment varies from person to person, with a minimum of one day and up to several weeks. This process depends on the severity of the disease, the effect of non-surgical treatment options, and the recovery ability of the individual. 18 Once the patient has surgical indications, a timely and appropriate surgical strategy is essential for the success of the operation and postoperative recovery. The relevant diagnostic information obtained by rapid and accurate preoperative imaging examination can help clinicians formulate the best operation strategy to reduce operation time, improve treatment effects, and reduce disease recurrence. At present, perianal ultrasound is the most commonly used preoperative imaging tool for perianal abscesses. In this study, the accuracy of pelvic CT in diagnosing the type of perianal abscess, the location of the perianal abscess, and the internal opening of the perianal abscess were 100%, 93.94%, and 81.82%, respectively. Studies have shown that the accuracy of perianal ultrasound in diagnosing the type of perianal abscess is 50-83.8%, the accuracy of diagnosing the location of perianal abscess is 75-85%, and the accuracy of diagnosing the internal opening of perianal abscess is 73%. 19 Singh et al. found that the accuracy of MRI in diagnosing the type of perianal abscess was 95-100%, the accuracy of diagnosing the location of the perianal abscess was more than 90%, and the accuracy of diagnosing the internal opening of the perianal abscess was 96%. 20 Through indirect comparison, we found that the accuracy of pelvic CT in diagnosing the type of perianal abscess was significantly better than that of perianal ultrasound and slightly better than MRI, the accuracy of diagnosing the location of the perianal abscess was higher than that of perianal ultrasound and MRI, and the accuracy of diagnosing the internal opening of the perianal abscess was significantly better than that of perianal ultrasound but lower than that of MRI. The internal opening of a perianal abscess usually refers to the channel or opening inside the abscess that communicates with the anal canal. The internal opening is usually located in the local part of the perianal abscess and is part of the soft tissue. 21 Some studies have shown that because the soft tissue resolution of pelvic CT is lower than that of MRI, the accuracy of diagnosing the internal opening of perianal abscess is lower than that of MRI. 22 In this study, the accuracy of pelvic CT has no obvious disadvantage compared with MRI, which may be related to the higher reading level of clinicians in our hospital. In China's public third-tier hospitals in second-third-tier cities, pelvic CT takes 5-10 minutes and costs RMB 100-200. 23 Perianal ultrasound takes 10-15 minutes and costs about RMB 100; MRI tests are longer and more expensive than perianal ultrasound and pelvic CT.(ranging from 30 minutes to 1 hour, with an average cost of 1,000 yuan) 24 Through indirect comparison, we found that the time and cost of pelvic CT in diagnosing perianal abscess was similar to that of perianal ultrasound. However, it was significantly better than MRI, suggesting that a pelvic CT scan has a better economic and time advantage in the preoperative diagnosis of perianal abscess. This is mainly due to the use of magnetic resonance imaging in MRI, signal acquisition is slow, scanning time is longer, and MRI examination requires patients to cooperate with more preparation, such as patients can not wear metal products during the examination.In addition, there are more taboos on MRI examination: for example, some claustrophobic patients cannot cooperate reasonably with the examination; obese patients do not quickly enter the scan chamber, and even if they do, the image may not be apparent due to physical contact with the coil; patients with pacemakers or magnetic medical devices in their bodies are restricted; critically ill patients who cannot cooperate reasonably or patients with monitoring systems and life support systems cannot enter the magnet room. However, ultrasonic imaging has low spatial resolution and limited accuracy in three-dimensional reconstruction, and ultrasonic images can not be continuously collected (ultrasound technicians can only collect a small number of pictures, according to experience). Therefore, it is difficult for clinicians to make accurate ultrasound reports by analyzing images and evaluating ultrasound features quickly. At the same time, a perianal ultrasound examination will inevitably squeeze the abscess site of the patient, which is easy to aggravate the pain and discomfort of the patient. If the abscess is deep, the abscess needs to be squeezed by the ultrasonic probe to a deeper level, and the pain is more prominent. Pelvic CT can carry out accurate three-dimensional reconstruction, doctors can consult continuous images at any time, and clinicians can quickly learn to read and distinguish pelvic CT images through short-term training, which is helpful for anorectal surgeons to determine the location and internal orifice of perianal abscess according to specialist experience and to judge the depth of perianal abscess. In addition, pelvic CT uses X-ray to image the different transmittance of different human body tissues, and there is no physical contact with the abscess site of the patient. Therefore, compared with ultrasound, it has the advantage of being painless or will not aggravate the pain. 25 In summary, pelvic CT is expected to be used as a first-line imaging tool for preoperative diagnosis of perianal abscess to help anorectal surgeons choose the correct surgical path. This study also has some limitations: first, the sample size is small, mainly because the imaging technicians in our hospital work in shifts and the personnel are relatively unstable, which leads to the inconsistent scanning range of different patients and is excluded, which significantly affects the sample size included. Therefore, the imaging technician should be fixed as far as possible in the relevant clinical trials. Second, there needs to be a more direct comparison between pelvic CT, MRI, and perianal ultrasound, which needs to be realized by further clinical control studies. Third, the quality of the pelvic CT diagnosis report depends on the reading level of anorectal surgeons and radiologists. To sum up, pelvic CT has high accuracy in diagnosing the type, location, and internal opening of the perianal abscess. It is a safe, accurate, economical, and effective tool for preoperative imaging diagnosis of perianal abscess. It is suggested that anorectal surgeons should choose pelvic CT as a tool for preoperative imaging 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. Supported by Sichuan Science and Technology Program (2022YFS0625). JL, JQW and XDY, came up with the study's concept. JL and XDY read pelvic CT, and JQW collected data and drew the images. JL and JQW conducted an analysis of the stats. JL, WJQ, XDY,YJW, WZH and LYL all provided their interpretations of the data. JL and JQW produced the initial draft. JL, JQW, XDY, and LYL critically evaluate the manuscript to see whether it contains any noteworthy intellectual content. All authors gave their approval to the final version. Disclosure forms provided by the authors are available with the full text of this article. A data sharing statement provided by the authors is available with the full text of this article. We thank the authors of all other studies that provided data. Declarations All methods were carried out in accordance with relevant guidelines and regulations. Approval was waived for this due to its retrospective nature. Informed consent was waived for this due to its retrospective nature. Acknowledgement: Not applicable. Funding This work was supported by Sichuan Science and Technology Program (2022YFS0625); Declaration of Competing Interest Statement The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Data availability The datasets used and/or analysed during the current study available from the corresponding author on reasonable request. In this study ，Yaling Li has to be contacted in case of any queries or requirement of data.(Yaling Li: Affiliation and address: Department of Pharmacy, The Affiliated Hospital, Southwest Medical University, Luzhou 646000, Sichuan, China. Email address: [email protected] . Telephone number: 15351290015.) Author Contribution JL, JQW and XDY, came up with the study's concept. JL and XDY read pelvic CT, and JQW collected data and drew the images. JL and JQW conducted an analysis of the stats. JL, WJQ, XDY,YJW, WZH and LYL all provided their interpretations of the data. JL and JQW produced the initial draft. JL, JQW, XDY, and LYL critically evaluate the manuscript to see whether it contains any noteworthy intellectual content. 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Gut 1995, 36: 407–10. Schwartz DA, Wiersema MJ, Dudiak KM, et al. A comparison of endoscopic ultrasound, magnetic resonance imaging, and exam under anesthesia for evaluation of Crohn's perianal fistulas. Gastroenterology 2001, 121: 1064–72. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4621204","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":328773865,"identity":"fdd412ea-efc3-40ff-815c-9efd9c2b8726","order_by":0,"name":"Jun Li","email":"","orcid":"","institution":"The Affiliated Hospital of Southwest Medical University","correspondingAuthor":false,"prefix":"","firstName":"Jun","middleName":"","lastName":"Li","suffix":""},{"id":328773866,"identity":"45b75035-f8f9-4059-b7fd-0f1a36ddf778","order_by":1,"name":"Jiaqi Wei","email":"","orcid":"","institution":"Southwest Medical University","correspondingAuthor":false,"prefix":"","firstName":"Jiaqi","middleName":"","lastName":"Wei","suffix":""},{"id":328773868,"identity":"c286d5cc-7a14-4a9c-8402-004be1206080","order_by":2,"name":"Yujiao Wu","email":"","orcid":"","institution":"Southwest Medical University","correspondingAuthor":false,"prefix":"","firstName":"Yujiao","middleName":"","lastName":"Wu","suffix":""},{"id":328773869,"identity":"25bb37b7-3040-46e6-9a30-6d72c8c88de6","order_by":3,"name":"Weizheng Huang","email":"","orcid":"","institution":"Southwest Medical University","correspondingAuthor":false,"prefix":"","firstName":"Weizheng","middleName":"","lastName":"Huang","suffix":""},{"id":328773871,"identity":"5343a52f-1fbf-476b-ad19-155667620149","order_by":4,"name":"Xiangdong Yang","email":"","orcid":"","institution":"Chengdu University of traditional Chinese Medicine","correspondingAuthor":false,"prefix":"","firstName":"Xiangdong","middleName":"","lastName":"Yang","suffix":""},{"id":328773872,"identity":"d2dee2ac-6508-461e-86c0-a882ec8f8529","order_by":5,"name":"Yaling Li","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABBUlEQVRIiWNgGAWjYBACPgbmBhCdAOFWQIV58GhhY2AEaTGAajlDshbGNmK0SCQ2fi6o+JPHz3742WfeeXWJa2ckMD5428Ygb45bS7P0jDMGxZI9acazebcdTtx2I4HZcG4bg+HOBpxaGqR52wwSN9xgMGbm3XYgF6iFDSjCkGBwALctv0Fa9t9g/8zMO6cOpIX9NwEtbRBbJHiAtjQwg21hxquF52Gb9YwzxokzzuQUM845drh+25mHzZJzzkkYbsChhZ89+fDtggq5xP7245sZ3tTUGZsdTz744U2ZjTwuWxgEEhiYYWwmSHSAY0oCh3qQNQcQWhh/4FY3CkbBKBgFIxgAAJYbWxELvU3jAAAAAElFTkSuQmCC","orcid":"","institution":"The Affiliated Hospital of Southwest Medical University","correspondingAuthor":true,"prefix":"","firstName":"Yaling","middleName":"","lastName":"Li","suffix":""}],"badges":[],"createdAt":"2024-06-22 09:29:45","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4621204/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4621204/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":61183814,"identity":"132ed565-8b70-4f69-8987-77781a02a458","added_by":"auto","created_at":"2024-07-26 17:08:37","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":230496,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eLocation Resolution of Perianal Abscess (Lithotomy Position)\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-4621204/v1/99418b0145f1721e516a26b6.png"},{"id":63246599,"identity":"2c6d6b5c-3deb-41a7-8b0e-9c7eaa6e6bbb","added_by":"auto","created_at":"2024-08-26 05:58:49","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":948220,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4621204/v1/9ee7154c-f3b6-43ac-a718-789a32d5a2fa.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Pelvic CT as a First-line Imaging Tool for Diagnosis of Perianal Abscess: A Single-center Retrospective Study","fulltext":[{"header":"Introduction","content":"\u003cp\u003ePerianal abscess\u0026nbsp;is an acute suppurative infection that occurs in the soft tissue or space around the anus and rectum.\u003csup\u003e1\u0026nbsp;\u003c/sup\u003eAccording to the location, a perianal abscess can be divided into two types: deep and superficial.\u003csup\u003e2\u003c/sup\u003e The perianal symptoms of patients with deep perianal abscess are not severe, mainly manifested as anal distension, sense of defecation, local skin temperature rise, and even accompanied by fever and other systemic symptoms; at this time the finger examination of rectal wall bulge, tenderness is apparent, fluctuation is also more apparent.\u003csup\u003e3\u0026nbsp;\u003c/sup\u003eThe patients with superficial perianal abscesses mainly showed redness, swelling, fever, pain, and other symptoms. At this time, there was a hard mass around the anus, and there was apparent fluctuation when the abscess matured.\u003csup\u003e4\u0026nbsp;\u003c/sup\u003eAccording to research, the incidence of perianal abscess in China is 0.16%-0.24%, while that in the United States is as high as 0.5%-1.0%.\u003csup\u003e5\u0026nbsp;\u003c/sup\u003eWith the development of society and the change in people\u0026apos;s dietary structure, the prevalence rate of perianal abscess increased obviously.\u003csup\u003e6\u0026nbsp;\u003c/sup\u003eThe diagnosis is relatively easy because of the prominent clinical symptoms and signs of perianal abscess. The disease is progressing rapidly, and the first-line treatment recommended by the American Association of Colorectal Surgeons Clinical practice guidelines and the Chinese Clinical diagnosis and treatment of Perianal abscess (2018 version) are timely incision and drainage (surgical drainage) and antibiotic treatment.Once incision and drainage are delayed, perianal abscesses are likely to continue to spread to deep and surrounding tissues or even develop into widespread systemic infections and life-threatening, such as pelvic abscesses, septic shock, sepsis, and necrotizing fasciitis, with mortality rates of 20%, 30%, 20%, 50%, and 80%, respectively. \u003csup\u003e7\u003c/sup\u003e\u003c/p\u003e\n\u003cp\u003eTo make timely and accurate incision and drainage for patients, it is essential to quickly and accurately determine the type, location, and internal opening of perianal abscess before operation, which can significantly reduce tissue injury and effectively protect anal function to improve the cure rate.\u003csup\u003e8\u003c/sup\u003e Physical examination can reveal symptoms such as redness, swelling, heat, and pain. In contrast, imaging examinations such as ultrasound, MRI, and CT have been shown in clinical practice to provide doctors with accurate diagnostic information to help guide surgery.\u003csup\u003e9\u0026nbsp;\u003c/sup\u003eTherefore, anal examination and perianal ultrasound are commonly used to determine the location and internal opening of perianal abscesses in St. Mark\u0026apos;s Hospital in the United Kingdom and Sloan-Catelyn Cancer Center in the United States. In contrast, anal examination, perianal ultrasound, or MRI are commonly used in Peking Union Medical College Hospital in China to determine the location and internal opening of the perianal abscess. Perianal ultrasound can clearly show the location and size of perianal abscesses and the anatomical structure of adjacent tissues and can guide the drainage of abscesses or aspiration of pus.\u003csup\u003e10\u0026nbsp;\u003c/sup\u003eHowever, the ability to locate and evaluate deep abscesses or complex abscesses is limited. The research of Gkegkes et al. also confirmed this point. (Gkegkes ID, Stamatiadis AP, et al. Anal Pain of an Unusual Cause: Role of Endoanal Ultrasound. J Med Ultrasound 2019, 27: 107-109.) MRI has good soft tissue contrast, can clearly show the structural characteristics of perianal abscess, and low radiation dose to patients. However, there are limitations in patients who are intolerant to confined spaces or have metallic foreign bodies. The examination cost is high, and the time is long, so it is unsuitable for diseases with rapid progression, such as perianal abscess. \u003csup\u003e11\u003c/sup\u003e\u003c/p\u003e\n\u003cp\u003eAccurate and rapid preoperative imaging diagnosis is of great practical significance for clinicians to determine the best surgical plan according to the progressive characteristics of the perianal abscess. Some studies have found that pelvic CT can provide comprehensive perianal and pelvic anatomical information, better locate and evaluate deep or complex perianal abscesses, and even detect other potential pelvic lesions.\u003csup\u003e12\u0026nbsp;\u003c/sup\u003eCompared with MRI and perianal ultrasound, CT takes less time, which is very helpful for preoperative evaluation and operation planning of perianal abscess.\u003csup\u003e13\u0026nbsp;\u003c/sup\u003eGiven this, the research group tried to prospectively use pelvic CT as an imaging diagnostic tool to guide anorectal surgeons to perform surgery before perianal abscess surgery. To clarify the preoperative diagnostic value of pelvic CT in perianal abscess, the authors conducted a retrospective study of patients with perianal abscess treated in our hospital from March 1, 2023, to June 30, 2023. By comparing the diagnostic results of pelvic CT and intraoperative observation, the diagnostic accuracy of pelvic CT in the type, location, and internal orifice of perianal abscess was obtained, and the diagnostic value of pelvic CT in perianal abscess was discussed by indirect comparison. Thus, it provides evidence-based basis for pelvic CT as a first-line preoperative imaging diagnostic tool for perianal abscess to enter the guide for diagnosis and treatment of perianal abscess.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e\u003cstrong\u003ePARTICIPANTS\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePatients with perianal abscesses treated in the anorectal department affiliated with the Hospital of Southwest Medical University from March 1, 2023, to June 30, 2023.Approval was waived for this due to its retrospective nature. Informed consent was waived for this due to its retrospective nature.All methods were carried out in accordance with relevant guidelines and regulations.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eINCLUSION AND EXCLUSION CRITERIA\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eInclusion criteria: complete medical history information of patients with perianal abscess; Have surgical indications and undergo surgery; pelvic CT examination before operation (if the patient is a pregnant woman, pelvic CT examination is not recommended). Exclusion criteria: No pelvic CT examination was performed before the operation. The lowest scanning part of pelvic CT is higher than the ischial tubercle, which affects regular reading.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCT ASSESSMENT\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe radiation technologist of the affiliated Hospital of Southwest Medical University collected the results of pelvic CT examination with a 64-slice CT scanner (Erlangen Siemens Health Company, Germany). The patients were supine (legs extended and fixed on pedals). Scan parameters: 120kVp tube voltage, and use automatic exposure control to adjust the tube current according to the patient\u0026apos;s size and body weight. The collimation is 0.6mm \u0026times; 64, the rotation time is 0.8s, the pitch is 1.0750, and the FOV is 300.0mm. All images were reconstructed with standard soft tissue nucleus, slice thickness was 3mm, and 2mm was thickened.\u003c/p\u003e\n\u003cp\u003ePelvic CT was read by experienced anorectal surgeons and radiologists, focusing on the sphincter signal: the position of the perianal abscess was judged according to the anal coccyx ligament (lithotomy position, \u003cstrong\u003eFigure 1\u003c/strong\u003e ). When necessary, combined with the inversion signal MPR (multiplanar reconstruction), a report (including at least the type, location, and internal opening of perianal abscess) was generated from multiple angles of cross-section, sagittal plane, and coronal plane.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSURGICAL TREATMENT\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFixed anorectal surgeons performed surgery according to pelvic CT diagnosis report and intraoperative exploration: One-time incision and drainage of perianal abscess, including internal opening treatment, were performed for a perianal abscess with the definite internal opening, while simple incision and drainage were performed for a perianal abscess with the unclear internal opening. Suppose it is found that the diagnosis of pelvic CT is not consistent with the actual situation of intraoperative exploration. In that case, the corresponding plan should be made according to the patient\u0026apos;s actual situation and the operator\u0026apos;s clinical experience. Special personnel recorded the operation process in detail, including the type, location, and internal opening of the perianal abscess.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDATA COLLECTION\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe research group obtained data from patient medical records, including basic information about patients, surgical records, pelvic CT diagnosis reports, and so on. Surgical records were used as the gold standard to judge whether the pelvic CT diagnosis was accurate.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSTATISTICAL ANALYSIS\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe statistical software SPSS26.0 and the WPS Office version 11 system were used for data processing and analysis. Counting data is expressed as a numerical value or percentage (%), and Continuous variables are expressed as mean \u0026plusmn;standard deviation. \u0026chi; 2 test was used for classified variables, and the t-test was used for continuous variables. P \u0026lt; 0.05 was considered statistically significant to evaluate the difference between groups.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003eGENERAL CLINCAL DATA OF THE PATIENTS\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA total of 176 cases of perianal abscess were obtained in this study. After careful exclusion, 33 patients were included in the study, including 30 males (91%) and 3 females (9%), with an average age of 47.13 \u0026plusmn;14.35 (20-81 years) and an average weight of 54.59 \u0026plusmn;13.84kg. The average course of the disease was 4 days, the shortest was 1 day, and the longest was 13 days. The severity of the disease varied, including 15 (45%) mild, 11 (33%) moderate, and 7 (21%) severe.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTHE ACTUAL SITUATION OBSERVED DURING THE OPERATION\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAccording to intraoperative exploration, anorectal surgeons found that there were 33 cases of perianal abscesses, including 19 cases of deep abscesses and 14 cases of superficial abscesses. Location of perianal abscess: Of the 33 patients, 7 (21%) were located in the anterior left, 2 (6%) in the anterior right, 8 (24%) in the right posterior, 4 (12%) in the right posterior, 2 (6%) in the anterior center, 8 (24%) in the posterior center, 1 (3%) in the left center, and 1 (3%) in the right center. The internal opening of perianal abscess: Of the 33 patients, 8 (24%) were at 0-3 o\u0026apos;clock (including 3 o\u0026apos;clock), 20 (61%) at 3-6 o\u0026apos;clock (including 6 o\u0026apos;clock), 4 (12%) at 6-9 o\u0026apos;clock (including 9 o\u0026apos;clock), 1 (3%) at 9-12o\u0026apos;clock (including 12 o\u0026apos;clock), as detailed in \u003cstrong\u003eTable 1.\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"99%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"100%\" colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 1.\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eActual Results Observed During Operation\u003c/strong\u003e\u003cstrong\u003e*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ePatients, No.\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTypes of perianal abscesses\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eLocations of Perianal abscess\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eInternal opening\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft anterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003efront center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e7 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft anterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e1 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft anterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e1 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003efront center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e2 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eback center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft anterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e1 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e4 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eback center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e11 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eright posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eback center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e5-6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eright anterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e4 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft anterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e1 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e5 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eback center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft anterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e2 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e5 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eback center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e5-6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eright posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e7 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eback center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e2 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft anterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e5-6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eright posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e2-3 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eright anterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e9 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e4-6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e28\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eback center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eright posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e4-5 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eback center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e9 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eright center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e*Note:\u003cstrong\u003eA\u003c/strong\u003e=deep abscess，\u003cstrong\u003eB\u003c/strong\u003e=superficial abscess\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDIAGNOSTIC RESULTS OF PELVIC CT SCAN\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAccording to the diagnosis report of pelvic CT scan before operation, it was found that there were 33 cases of perianal abscess, including 19 cases of deep abscess and 14 cases of superficial abscess. Location of perianal abscess: Of the 33 patients, 6 (18%) were located in the anterior left, 3 (8%) in the anterior right, 7 (21%) in the left posterior, 5 (15%) in the right posterior, 2 (6%) in the anterior center, 8 (24%) in the posterior center, 1 (3%) in the left center and 1 (3%) in the right center.Internal opening of perianal abscess: Among the 33 patients, 11 (33%) were at 0-3 o\u0026apos;clock position (including 3 o\u0026apos;clock position), 18 (55%) cases were at 3-6 o\u0026apos;clock position (including 6 o\u0026apos;clock position), 2 (6%) cases were at 6-9 o\u0026apos;clock position (including 9 o\u0026apos;clock position), 2 (6%) cases were at 9-12 o\u0026apos;clock position (including 12 o\u0026apos;clock), details are shown in \u003cstrong\u003eTable 2\u003c/strong\u003e.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"99%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"100%\" colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 2.\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eDiagnosis of Pelvic CT Scan\u003c/strong\u003e\u003cstrong\u003e*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ePatients, No.\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTypes of perianal abscesses\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eLocations of Perianal abscess\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eInternal opening\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft anterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003efront center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e2 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft anterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e1 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003efront center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e1 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eback center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft anterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e1 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e4 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eback center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e11 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eright posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e3 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eback center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e5-6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eright anterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e4 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft anterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e1 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e5 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eback center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft anterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e3 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e5 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eback center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e5-6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eright posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e7 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e22\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eback center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e2 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e23\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eright anterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e1 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e24\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e5-6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eright posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e2-3 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"100%\" colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 2.\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003e(Continued.)\u003c/strong\u003e\u003cstrong\u003e*\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003ePatients, No.\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTypes of perianal abscesses\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eLocations of Perianal abscess\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eInternal opening\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e26\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eright anterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e9 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e4-6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e28\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eleft posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e29\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eback center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eright posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e4-5 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eright posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e32\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eB\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eback center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e11 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"18.181818181818183%\" valign=\"top\"\u003e\n \u003cp\u003e33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"28.282828282828284%\" valign=\"top\"\u003e\n \u003cp\u003eright center.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"25.252525252525253%\" valign=\"top\"\u003e\n \u003cp\u003e6 o \u0026apos;clock\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e*\u003c/strong\u003eNote:\u003cstrong\u003eA\u003c/strong\u003e=deep abscess，\u003cstrong\u003eB\u003c/strong\u003e=superficial abscess\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDIAGNOSTIC ACCURACY OF PELVIC CT\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTaking the actual results observed during the operation as the reference standard, the differences between the diagnostic results of pelvic CT and the actual results observed during the operation were compared. Type of perianal abscess: compared with the actual intraoperative results, the accuracy of pelvic CT scanning of deep abscess and superficial abscess was 100%. Location of perianal abscess: compared with the actual intraoperative results, 31 of the 33 patients were diagnosed correctly, with an accuracy of 93.94%. The internal opening of perianal abscess: compared with the actual intraoperative results, 27 of the 33 patients were diagnosed correctly, with an accuracy of 81.82%. Details are shown in \u003cstrong\u003eTable 3-5\u003c/strong\u003e.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"100%\" colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 3.\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eAccuracy of Pelvic CT in the Diagnosis of Perianal Abscess Type (n,%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.742268041237114%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003esurgical records(n)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.711340206185568%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eCorrect pelvic CT(n)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.804123711340207%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eAccuracy(%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\" valign=\"top\"\u003e\n \u003cp\u003edeep abscess\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.742268041237114%\" valign=\"top\"\u003e\n \u003cp\u003e19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.711340206185568%\" valign=\"top\"\u003e\n \u003cp\u003e19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.804123711340207%\" valign=\"top\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\" valign=\"top\"\u003e\n \u003cp\u003esuperficial abscess\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.742268041237114%\" valign=\"top\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.711340206185568%\" valign=\"top\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.804123711340207%\" valign=\"top\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"100%\" colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 4.\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eAccuracy of Pelvic CT for the Location of Perianal Abscess (n,%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.471830985915492%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.823943661971832%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eSurgical records(n)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.471830985915492%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eCorrect pelvic CT(n)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.232394366197184%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eAccuracy(%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.471830985915492%\" valign=\"top\"\u003e\n \u003cp\u003eleft anterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.823943661971832%\" valign=\"top\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.471830985915492%\" valign=\"top\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.232394366197184%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.471830985915492%\" valign=\"top\"\u003e\n \u003cp\u003eright anterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.823943661971832%\" valign=\"top\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.471830985915492%\" valign=\"top\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.232394366197184%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.471830985915492%\" valign=\"top\"\u003e\n \u003cp\u003eleft posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.823943661971832%\" valign=\"top\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.471830985915492%\" valign=\"top\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.232394366197184%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.471830985915492%\" valign=\"top\"\u003e\n \u003cp\u003eright posterior\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.823943661971832%\" valign=\"top\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.471830985915492%\" valign=\"top\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.232394366197184%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.471830985915492%\" valign=\"top\"\u003e\n \u003cp\u003efront center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.823943661971832%\" valign=\"top\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.471830985915492%\" valign=\"top\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.232394366197184%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.471830985915492%\" valign=\"top\"\u003e\n \u003cp\u003eback center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.823943661971832%\" valign=\"top\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.471830985915492%\" valign=\"top\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.232394366197184%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.471830985915492%\" valign=\"top\"\u003e\n \u003cp\u003eleft center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.823943661971832%\" valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.471830985915492%\" valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.232394366197184%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.471830985915492%\" valign=\"top\"\u003e\n \u003cp\u003eright center\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.823943661971832%\" valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.471830985915492%\" valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.232394366197184%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.471830985915492%\" valign=\"top\"\u003e\n \u003cp\u003eTotal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.823943661971832%\" valign=\"top\"\u003e\n \u003cp\u003e33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.471830985915492%\" valign=\"top\"\u003e\n \u003cp\u003e31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.232394366197184%\" valign=\"top\"\u003e\n \u003cp\u003e93.94\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"100%\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd width=\"100%\" colspan=\"4\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eTable 5.\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eAccuracy of Pelvic CT for Diagnosis of Internal Opening (n,%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eVariables\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.742268041237114%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eSurgical records(n)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.711340206185568%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eCorrect pelvic CT(n)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.804123711340207%\" valign=\"top\"\u003e\n \u003cp\u003e\u003cstrong\u003eAccuracy(%)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\" valign=\"top\"\u003e\n \u003cp\u003e0-3 o \u0026apos;clock position\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.742268041237114%\" valign=\"top\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.711340206185568%\" valign=\"top\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.804123711340207%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\" valign=\"top\"\u003e\n \u003cp\u003e3-6 o \u0026apos;clock position\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.742268041237114%\" valign=\"top\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.711340206185568%\" valign=\"top\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.804123711340207%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\" valign=\"top\"\u003e\n \u003cp\u003e6-9 o \u0026apos;clock position\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.742268041237114%\" valign=\"top\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.711340206185568%\" valign=\"top\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.804123711340207%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\" valign=\"top\"\u003e\n \u003cp\u003e9-12 o \u0026apos;clock position\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.742268041237114%\" valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.711340206185568%\" valign=\"top\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.804123711340207%\" valign=\"top\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd width=\"24.742268041237114%\" valign=\"top\"\u003e\n \u003cp\u003eTotal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"24.742268041237114%\" valign=\"top\"\u003e\n \u003cp\u003e33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"23.711340206185568%\" valign=\"top\"\u003e\n \u003cp\u003e27\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd width=\"26.804123711340207%\" valign=\"top\"\u003e\n \u003cp\u003e81.82\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"Discussion","content":"\u003cp\u003ePerianal abscess is a widespread disease, and the incidence rate is as high as 10% -20% in some high-risk groups such as anal foreign body, anal fissure, rectal fistula, and other patients. \u003csup\u003e14\u0026nbsp;\u003c/sup\u003eIn addition, people who are sedentary or have limited movement, such as office workers and long-term bedridden patients, are also more likely to develop perianal abscesses.\u003csup\u003e15\u0026nbsp;\u003c/sup\u003eEarly, small perianal abscesses can be relieved and cured by non-operative programs (such as drug treatment, hot compress, etc.). If recurrence occurs after non-operative treatment, or the abscess persists, or the abscess spreads to surrounding tissue causing perianal infection or affecting sphincter function, or there are other complications such as anal fistula, surgery should be performed immediately.\u003csup\u003e16\u0026nbsp;\u003c/sup\u003eSurgery can effectively drain and remove infection, thus quickly eliminating inflammation and abscesses and reducing symptoms such as pain and discomfort.\u003csup\u003e17\u0026nbsp;\u003c/sup\u003eThe time from the early stage of perianal abscess to the need for surgical treatment varies from person to person, with a minimum of one day and up to several weeks. This process depends on the severity of the disease, the effect of non-surgical treatment options, and the recovery ability of the individual.\u003csup\u003e18\u0026nbsp;\u003c/sup\u003eOnce the patient has surgical indications, a timely and appropriate surgical strategy is essential for the success of the operation and postoperative recovery. The relevant diagnostic information obtained by rapid and accurate preoperative imaging examination can help clinicians formulate the best operation strategy to reduce operation time, improve treatment effects, and reduce disease recurrence.\u003c/p\u003e\n\u003cp\u003eAt present, perianal ultrasound is the most commonly used preoperative imaging tool for perianal abscesses. In this study, the accuracy of pelvic CT in diagnosing the type of perianal abscess, the location of the perianal abscess, and the internal opening of the perianal abscess were 100%, 93.94%, and 81.82%, respectively. Studies have shown that the accuracy of perianal ultrasound in diagnosing the type of perianal abscess is 50-83.8%, the accuracy of diagnosing the location of perianal abscess is 75-85%, and the accuracy of diagnosing the internal opening of perianal abscess is 73%. \u003csup\u003e19\u0026nbsp;\u003c/sup\u003eSingh et al. found that the accuracy of MRI in diagnosing the type of perianal abscess was 95-100%, the accuracy of diagnosing the location of the perianal abscess was more than 90%, and the accuracy of diagnosing the internal opening of the perianal abscess was 96%. \u003csup\u003e20\u0026nbsp;\u003c/sup\u003eThrough indirect comparison, we found that the accuracy of pelvic CT in diagnosing the type of perianal abscess was significantly better than that of perianal ultrasound and slightly better than MRI, the accuracy of diagnosing the location of the perianal abscess was higher than that of perianal ultrasound and MRI, and the accuracy of diagnosing the internal opening of the perianal abscess was significantly better than that of perianal ultrasound but lower than that of MRI. The internal opening of a perianal abscess usually refers to the channel or opening inside the abscess that communicates with the anal canal. The internal opening is usually located in the local part of the perianal abscess and is part of the soft tissue. \u003csup\u003e21\u0026nbsp;\u003c/sup\u003eSome studies have shown that because the soft tissue resolution of pelvic CT is lower than that of MRI, the accuracy of diagnosing the internal opening of perianal abscess is lower than that of MRI.\u003csup\u003e22\u0026nbsp;\u003c/sup\u003eIn this study, the accuracy of pelvic CT has no obvious disadvantage compared with MRI, which may be related to the higher reading level of clinicians in our hospital. In China\u0026apos;s public third-tier hospitals in second-third-tier cities, pelvic CT takes 5-10 minutes and costs RMB 100-200. \u003csup\u003e23\u003c/sup\u003e Perianal ultrasound takes 10-15 minutes and costs about RMB 100; MRI tests are longer and more expensive than perianal ultrasound and pelvic CT.(ranging from 30 minutes to 1 hour, with an average cost of 1,000 yuan)\u003csup\u003e24\u003c/sup\u003e Through indirect comparison, we found that the time and cost of pelvic CT in diagnosing perianal abscess was similar to that of perianal ultrasound. However, it was significantly better than MRI, suggesting that a pelvic CT scan has a better economic and time advantage in the preoperative diagnosis of perianal abscess. This is mainly due to the use of magnetic resonance imaging in MRI, signal acquisition is slow, scanning time is longer, and MRI examination requires patients to cooperate with more preparation, such as patients can not wear metal products during the examination.In addition, there are more taboos on MRI examination: for example, some claustrophobic patients cannot cooperate reasonably with the examination; obese patients do not quickly enter the scan chamber, and even if they do, the image may not be apparent due to physical contact with the coil; patients with pacemakers or magnetic medical devices in their bodies are restricted; critically ill patients who cannot cooperate reasonably or patients with monitoring systems and life support systems cannot enter the magnet room. However, ultrasonic imaging has low spatial resolution and limited accuracy in three-dimensional reconstruction, and ultrasonic images can not be continuously collected (ultrasound technicians can only collect a small number of pictures, according to experience). Therefore, it is difficult for clinicians to make accurate ultrasound reports by analyzing images and evaluating ultrasound features quickly. At the same time, a perianal ultrasound examination will inevitably squeeze the abscess site of the patient, which is easy to aggravate the pain and discomfort of the patient. If the abscess is deep, the abscess needs to be squeezed by the ultrasonic probe to a deeper level, and the pain is more prominent. Pelvic CT can carry out accurate three-dimensional reconstruction, doctors can consult continuous images at any time, and clinicians can quickly learn to read and distinguish pelvic CT images through short-term training, which is helpful for anorectal surgeons to determine the location and internal orifice of perianal abscess according to specialist experience and to judge the depth of perianal abscess. In addition, pelvic CT uses X-ray to image the different transmittance of different human body tissues, and there is no physical contact with the abscess site of the patient. Therefore, compared with ultrasound, it has the advantage of being painless or will not aggravate the pain.\u003csup\u003e25\u003c/sup\u003e In summary, pelvic CT is expected to be used as a first-line imaging tool for preoperative diagnosis of perianal abscess to help anorectal surgeons choose the correct surgical path.\u003c/p\u003e\n\u003cp\u003eThis study also has some limitations: first, the sample size is small, mainly because the imaging technicians in our hospital work in shifts and the personnel are relatively unstable, which leads to the inconsistent scanning range of different patients and is excluded, which significantly affects the sample size included. Therefore, the imaging technician should be fixed as far as possible in the relevant clinical trials. Second, there needs to be a more direct comparison between pelvic CT, MRI, and perianal ultrasound, which needs to be realized by further clinical control studies. Third, the quality of the pelvic CT diagnosis report depends on the reading level of anorectal surgeons and radiologists.\u003c/p\u003e\n\u003cp\u003eTo sum up, pelvic CT has high accuracy in diagnosing the type, location, and internal opening of the perianal abscess. It is a safe, accurate, economical, and effective tool for preoperative imaging diagnosis of perianal abscess. It is suggested that anorectal surgeons should choose pelvic CT as a tool for preoperative imaging 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.\u003c/p\u003e\n\u003cp\u003eSupported by Sichuan Science and Technology Program (2022YFS0625).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eJL, JQW and XDY, came up with the study\u0026apos;s concept. JL and XDY read pelvic CT, and JQW collected data\u0026nbsp;and\u0026nbsp;drew the images. JL and JQW conducted an analysis of the stats. JL, WJQ, XDY,YJW, WZH and LYL all provided their interpretations of the data. JL and JQW produced the initial draft. JL, JQW, XDY, and LYL critically evaluate the manuscript to see whether it contains any noteworthy intellectual content. All authors gave their approval to the final version.\u003c/p\u003e\n\u003cp\u003eDisclosure forms provided by the authors are available with the full text of this article.\u003c/p\u003e\n\u003cp\u003eA data sharing statement provided by the authors is available with the full text of this article.\u003c/p\u003e\n\u003cp\u003eWe thank the authors of all other studies that provided data.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eAll methods were carried out in accordance with relevant guidelines and regulations.\u003c/p\u003e\n\u003cp\u003eApproval was waived for this due to its retrospective nature. Informed consent was waived for this due to its retrospective nature.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgement:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by Sichuan Science and Technology Program (2022YFS0625);\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclaration of Competing Interest\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eStatement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used and/or analysed during the current study available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003eIn this study ，Yaling Li has to be contacted in case of any queries or requirement of data.(Yaling Li: Affiliation and address: Department of Pharmacy, The Affiliated Hospital, Southwest Medical University, Luzhou 646000, Sichuan, China. Email address: [email protected]. Telephone number: 15351290015.)\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contribution\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eJL, JQW and XDY, came up with the study\u0026apos;s concept. JL and XDY read pelvic CT, and JQW collected data and drew the images. JL and JQW conducted an analysis of the stats. JL, WJQ, XDY,YJW, WZH and LYL all provided their interpretations of the data. JL and JQW produced the initial draft. JL, JQW, XDY, and LYL critically evaluate the manuscript to see whether it contains any noteworthy intellectual content. All authors gave their approval to the final version.Disclosure forms provided by the authors are available with the full text of this article.A data sharing statement provided by the authors is available with the full text of this article.We thank the authors of all other studies that provided data.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eSahnan K, Adegbola SO, Tozer PJ, et al. Perianal abscess. BMJ 2017, 356: j475.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTsai L, McCurdy JD, Ma C, et al. Epidemiology and Natural History of Perianal Crohn's Disease: A Systematic Review and Meta-Analysis of Population-Based Cohorts. Inflamm Bowel Dis 2022, 28: 1477\u0026ndash;1484.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYin W, Li Y, Zhang J, et al. Natural course of perianal abscess in infants: a real-world study. Sci Rep 2023, 13: 18416.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAmato A, Bottini C, De Nardi P, et al. Evaluation and management of perianal abscess and anal fistula: SICCR position statement. Tech Coloproctol 2020, 24: 127\u0026ndash;143.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiang S, Ma W, Jia S, et al. Application of platelet-rich-plasma in the postoperative treatment of perianal abscess pseudohealing: A case report. Medicine (Baltimore). 2023;102(46):e35996.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAdamo K, Sandblom G, Br\u0026auml;nnstr\u0026ouml;m F, et al. Prevalence and recurrence rate of perianal abscess\u0026ndash;a population-based study, Sweden 1997\u0026ndash;2009. Int J Colorectal Dis 2016, 31: 669\u0026ndash;73.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAnaya DA, Dellinger, EP. Necrotizing soft-tissue infection: diagnosis and management. Clinical infectious diseases 44(5), 705\u0026ndash;710.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSkovgaards DM, Perregaard H, Hagen KB, et al. Treatment of anal abscesses. Ugeskr Laeger 2020, 182: undefined.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRipoll\u0026eacute;s Gonz\u0026aacute;lez T, Mart\u0026iacute;nez P\u0026eacute;rez MJ, Ultrasound, CT, and MRI in Crohn's disease. Radiologia 2007, 49: 97\u0026ndash;108.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eIsbert C, Germer CT. Impact of endoscopy and endosonography on local staging of rectal carcinoma. Chirurg 2012, 83: 430\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePham TT, Stait-Gardner T, Lee CS, et al. Correlation of ultra-high field MRI with histopathology for evaluation of rectal cancer heterogeneity. Sci Rep 2019, 9: 9311.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKoehler PR, Moss AA. Diagnosis of intra-abdominal and pelvic abscesses by computerized tomography. JAMA, 1980, 244: 49\u0026ndash;52.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMinordi LM, Bevere A, Papa A, et al. CT and MRI Evaluations in Crohn's Complications: A Guide for the Radiologist. Acad Radiol 2022, 29: 1206\u0026ndash;1227.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTsai L, McCurdy JD, Ma C, et al. Epidemiology and Natural History of Perianal Crohn's Disease: A Systematic Review and Meta-Analysis of Population-Based Cohorts. Inflamm Bowel Dis 2022, 28: 1477\u0026ndash;1484.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYamamoto T, Nakase H, Watanabe K, et al. Diagnosis and Clinical Features of Perianal Lesions in Newly Diagnosed Crohn's Disease: Subgroup Analysis from Inception Cohort Registry Study of Patients with Crohn's Disease (iCREST-CD). J Crohns Colitis 2023, 17: 1193\u0026ndash;1206.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePan\u0026eacute;s J, Rimola J. Perianal fistulizing Crohn's disease: pathogenesis, diagnosis and therapy. Nat Rev Gastroenterol Hepatol 2017, 14: 652\u0026ndash;664.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBowman JK. Abscess Incision and Drainage. Prim Care 2022, 49: 39\u0026ndash;45.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKaye TL, O'Connor A, Burke D, et al. A young woman with recurrent perianal sepsis. BMJ 2015, 350: h1969.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSingh A, Kaur G, Singh JI, et al. Role of Transcutaneous Perianal Ultrasonography in Evaluation of Perianal Fistulae with MRI Correlation. Indian J Radiol Imaging 2022, 32: 51\u0026ndash;61.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSingh K, Singh N, Thukral C, et al. 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Pelvic and perineal complications of Crohn's disease: assessment using magnetic resonance imaging. Gut 1995, 36: 407\u0026ndash;10.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSchwartz DA, Wiersema MJ, Dudiak KM, et al. A comparison of endoscopic ultrasound, magnetic resonance imaging, and exam under anesthesia for evaluation of Crohn's perianal fistulas. Gastroenterology 2001, 121: 1064\u0026ndash;72.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"","lastPublishedDoi":"10.21203/rs.3.rs-4621204/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4621204/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBACKGROUND\u0026nbsp;\u003c/strong\u003ePelvic CT\u0026nbsp;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. \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMETHODS \u003c/strong\u003eIn this retrospective study, we analyzed data from\u0026nbsp;patients with perianal abscesses treated in our hospital's department of anorectal department from March 1, 2023, to June 30, 2023.\u0026nbsp;All patients were examined by pelvic CT before the operation, and the type, location, and internal opening of the perianal abscess were recorded\u0026nbsp;intraoperatively.\u0026nbsp;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\u0026nbsp;surgery\u0026nbsp;was analyzed. \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eRESULTS \u003c/strong\u003eFinally, 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\u0026nbsp;cases were at 9-12o'clock position (including 12 o'clock position).\u0026nbsp;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%. \u0026nbsp;\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCONCLUSIONS \u003c/strong\u003ePelvic 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. \u0026nbsp;\u003c/p\u003e","manuscriptTitle":"Pelvic CT as a First-line Imaging Tool for Diagnosis of Perianal Abscess: A Single-center Retrospective Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-26 17:08:32","doi":"10.21203/rs.3.rs-4621204/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"3b1ce3d0-7f00-4234-90f4-96593738c821","owner":[],"postedDate":"July 26th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":34802664,"name":"Health sciences/Medical research"},{"id":34802665,"name":"Health sciences/Signs and symptoms"}],"tags":[],"updatedAt":"2024-08-26T05:50:42+00:00","versionOfRecord":[],"versionCreatedAt":"2024-07-26 17:08:32","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4621204","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4621204","identity":"rs-4621204","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}