Periappendiceal Fat Stranding as a Specific Tomographic Sign of Inflammatory and Noninflammatory Appendicopathies

Periappendiceal Fat Stranding as a Specific Tomographic Sign of Inflammatory and Noninflammatory Appendicopathies | 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 Research Article Periappendiceal Fat Stranding as a Specific Tomographic Sign of Inflammatory and Noninflammatory Appendicopathies Ana Helena Leandro Cordeiro, Carlos Teixeira Brandt, Andy Petroianu - This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8888276/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 5 You are reading this latest preprint version Abstract Background Appendicopathies are still ongoing diagnostic challenges, with a rate of morphologically normal appendix removals exceeding 20% due to limitations of the diagnostic exams and scores. The objective of this study was to verify the efficacy of periappendiceal fat stranding identified on computed tomography as a complementary exam in differentiating appendicopathies, specifying inflammatory and noninflammatory disorders. Methods A single-center, cross-sectional observational study was conducted on 200 consecutive patients of varying ages and both sexes submitted to appendectomy due to diagnosis of acute appendicitis. Medical records and imaging exams were assessed, including the Alvarado score and the periappendiceal fat stranding ranking level. This study compared inflammatory and noninflammatory appendicopathies. Statistical significance was set at p < 0.05, with prevalence ratios calculated at a 95% CI and ROC curve analyses applied. Results The exams used in the Alvarado score failed in predicting appendiceal inflammation confirmed by the histopathologic exams. High periappendiceal fat stranding (grades 2 and 3) showed a prevalence ratio of 1.57 (95% CI: 1.31–1.87). The ROC curve's area was 0.924, with grade 3 sensitivity at 74.86% and specificity at 100%, indicating strong predictive level. Conclusion Periappendiceal fat stranding identified on computed tomography scans is efficacious in identifying appendicopathies and in the differential diagnosis of inflammatory and noninflammatory disorders. Appendicitis Appendicopathy Fat stranding Histology Computed tomography Figures Figure 1 BACKGROUND Acute appendicitis (AA) is the most common cause of acute abdomen requiring surgical treatment, accounting for 10% of hospital emergency care, and its complications are related to high morbidity and mortality. [ 1 ] AA has been diagnosed through the patient's clinical history, physical examination, laboratory tests, and imaging exams, in addition to clinical scores, developed with the aim of increasing the sensitivity and specificity of a precise diagnosis. [ 1 – 12 ] Imaging exams in cases of patients with suspected AA increase the sensitivity, specificity and, above all, the accuracy of this diagnosis. Among these exams, ultrasound (US) [ 13 – 22 ] and computed tomography (CT) are the most commonly used. CT signs of inflammatory and noninflammatory appendiceal disorders may increase specificity, although it still persists with a low sensitivity degree, with around 20% of morphologically normal appendices removal. [ 11 ] In this context, the degree of periappendiceal fat stranding has proven to be a relevant sign in the differentiation of inflammatory and noninflammatory forms of appendicopathies. [ 23 – 34 ] The purpose of this study was to investigate the efficacy and clinical aspects associated with inflammatory appendicopathies and to verify the efficacy of the periappendiceal fat stranding in improving precise diagnosis of inflammatory and noninflammatory appendiceal disorders. METHODS The study protocol was developed in accordance with the ethical guidelines stipulated in Resolution No. 466/2012 of the Brazilian National Health Council (Ministry of Health, Brazil, 2012) and was approved by the Research Ethics Committee (CAAE 51272121.2.0000.5175). Data collection began only after obtaining informed consent from patients participating in the study. Additionally, The project was registered on the Open Science Framework platform to enhance the methodology's replicability and integrity, under the digital object identifier https://doi.org/10.17605/OSF.IO/54ZF3 . All patients were invited to participate in this study, and included only after they agreed and signed the Free and Informed Consent Term including the consent for publication. Consecutive adult (> 18 years old) patients who underwent appendectomy were invited to participate in this study. The selection process consisted of 200 patients, distributed in two groups based on postoperative histopathological diagnosis: - inflammatory appendicopathy (n = 175) and - noninflammatory appendicopathy (n = 25). Eligibility criteria required that participants have presented to the hospital with suspected appendiceal pain, completed all stages of the initial clinical examination, undergone abdominal computed tomography (CT), and subsequently undergone an appendectomy. Data collection started after participants signed the informed consent form. Anamnesis, Alvarado scoring, and surgery were performed by hospital professionals without specific involvement in the research. Histopathological examinations were conducted by two pathologists to ensure accurate diagnosis of inflammatory versus noninflammatory cases. The CT images were reviewed by two radiologists. Histopathological classification was based on the presence and severity of inflammation. Specimens were categorized as inflammatory appendicopathy if they exhibited diffuse lymphoplasmacytic infiltrate with neutrophil exudate dissociating the muscular and serosal layers and a fibrinoleukocytic crust indicative of ulcerophlegmonous 4 suppuration. In cases showing diffuse infiltration with neutrophils and cellular debris, perforation or necrosis was diagnosed. Noninflammatory appendicopathy was classified by the presence of lymphocyte infiltration, lymphoid hyperplasia, and wall edema with preserved appendiceal wall integrity. Regarding CT findings, radiologists focused on the degree of periappendiceal fat stranding, applying precisely differential criteria outlined in Fig. 1 . Radiologists were blinded to the histopathological outcomes of the resected appendices. Imaging was conducted on a Revolution Maxima CT scanner (GE Healthcare) with 64 channels and a 1.3 mm slice thickness. RadiAnt DICOM Viewer was used for image visualization. Preoperative CT scans of patients diagnosed with acute appendicitis, show four degrees of periappendiceal fat stranding. A - Grade 0 - cecal appendix within normal characteristics (*), and absence of periappendiceal fat stranding (arrow). B - Grade 1 - appendix increased in diameter and length (*), with low periappendiceal fat stranding (arrow). C - Grade 2 - appendix increased in diameter and length (*), with moderate periappendiceal fat stranding (arrows). D - Grade 3 - appendix increased in diameter and length (*), with high periappendiceal fat stranding and reticular shape (arrows). Following data collection, information was organized in Excel 2019, and statistical analyses were performed using Jamovi (1.6.21) with the psychoPDA – Psychometrics Post-Data Analysis package (1.0.5). Prevalence ratios with 95% confidence intervals were calculated to assess associations, with statistical significance defined as confidence intervals excluding 1. For association testing, fat stranding grades and Alvarado scores were dichotomized into high (grades 2 and 3 for fat stranding, related to scores 6 to 10 for Alvarado score) and low (grades 0 and 1 for fat stranding, related to scores 1 to 5 for Alvarado score). Group characteristics, such as age, hospital stay duration, and non-dichotomized Alvarado and fat stranding scores, were compared using the nonparametric Mann-Whitney test. Additionally, binomial regression analysis and ROC curve analysis were conducted to evaluate the diagnostic accuracy of the Alvarado score and periappendiceal fat stranding in relation to histopathological diagnosis, with inferential statistics considered significant at p < 0.05. RESULTS Patients characteristics, including clinical data, complementary exam results, Alvarado scores, and degrees of periappendiceal fat stranding, are summarized in Table 1. The periappendiceal fat stranding scores observed on CT scans ranged from 0 to 3, with a mean score of 2.05 ± 0.87 for patients diagnosed with inflammatory appendicopathy and 0.40 ± 0.50 for those with noninflammatory appendicopathy. A statistically significant association was found between the degree of periappendiceal fat stranding and histopathological classification (p < 0.001). Table 1 – Characteristics of patients operated on for acute appendicitis, their complementary exams, Alvarado score, and periappendiceal fat stranding criteria comparing distribution of histopathologic classification. PARAMETER APPENDICOPATHY Inflammatory (n = 175) Noninflammatory (n = 25) Male 103 15 Female 72 10 Age (years) 32.9 ± 14.5 28.6 ± 10.1 Fever 57 (32.6%) 12 (48.0%) Leukocytosis 141 (80.6%) 15 (60.0%) Left turn 84 (48.0%) 9 (36.0%) Hospitalization priod 1.75 ± 1.46 1.48 ± 0.82 Alvarado’s score 7.58 ± 1.68 7.36 ± 1.82 Degree of stranding 2.05 ± 0.87*** 0.40 ± 0.50*** Mean ± standard deviation of mean between groups; (%) = percentage of sample; *** = p < 0.001 (Mann-Whitney test). Given the cross-sectional design, a prevalence ratio analysis was conducted to examine associations between key variables and diagnostic accuracy for inflammatory versus noninflammatory cases. From the contingency table analysis presented in Table 2, histopathological classification was compared across variables such as sex, presence of leukocytosis, fever, left shift, degree of periappendiceal fat stranding, and Alvarado scores. In this study, no discrepancy occurred with the results of this parameter. A consensus was found in all included cases. The prevalence ratios with corresponding confidence intervals for these comparisons are present. To address the study's objective of supporting the diagnosis of appendiceal inflammation, the sensitivity and specificity of the degree of periappendiceal fat stranding. A strong predictive value of periappendiceal fat stranding, with grade 3 was identified as an optimal cut-off point, achieving 100% specificity and 74.86% sensitivity, with a positive predictive value of 100% and a negative predictive value of 36.23%. Patients with fat stranding grades of 2 to 3 (1.87, 95% confidence inervals) have a 1.57-fold higher prevalence ratio (PR) for an inflammatory profile compared to those with grades 0 and 1 (1.31, 95% confidence intervals). The PR of the other assessed parameters were not significant, as follows, sex (PR 1.10), leukocytosis (PR 1.17), fever (PR 1.09), left deviation (PR 1.06) and Alvarado score (PR 1.04). DISCUSSION This study, included only medical records with complete and undisputed data, even though records were prepared by different surgeons. Given this selective criterion, discrepancies between findings of this study and those in similarly designed studies may arise. [ 35 – 37 ] However, the thorough review of histopathological reports and tomographic image interpretations strengthens the reliability and standardization of the analyses of this work. Consequently, the findings regarding periappendiceal fat stranding serve as a dependable diagnostic criterion for AA. The clinical manifestations, complementary exams, and hospital stay duration observed in this study are consistent with existing literature on appendectomy patients. [ 37 ] However, it is noteworthy that the average age of patients with noninflammatory appendicopathy was lower than that of patients with appendicitis, although this difference was not significant. [ 8 ] The two groups compared in this study are uneven but the statistical results are reliable. While the mean age of patients in this study aligns with reported data in the literature, the incidence of male patients was higher than that of females and exceeded expected proportions. [ 24 ] Most clinical findings, including preoperative leukocytosis, also aligned with published data [ 2 , 38 ]. The incidence of pain upon sudden decompression at McBurney’s point diverged from the literature, although it is recognized that this sign can be absent in up to 70% of cases. [ 2 , 38 ] The findings regarding the Alvarado score in diagnosing AA contrast with the literature. [ 2 , 5 , 8 , 9 , 39 ] This study revealed that the Alvarado score lacks specificity and does not distinguish between inflammatory and noninflammatory appendicopathies. Therefore, the use of the Alvarado score in AA should be approached cautiously, especially given that it excludes imaging methods, which are the most sensitive and specific tools in diagnosing this condition. The semi-quantitative scoring of periappendiceal fat stranding observed via CT scans aids in differentiating inflammatory from noninflammatory appendiceal disorders more effectively. When combined with clinical findings and predictive risk scores, the degree of periappendiceal fat stranding enhances diagnostic accuracy, enabling a more precise assessment. [ 35 , 36 ] This method demonstrates high clinical reliability. Another advantage of periappendiceal fat stranding classification through CT imaging is its objectivity, with no variance between radiologists’ interpretations, which was easy and precisely defined. Routine application of this CT criterion may further reduce diagnostic inconsistencies among radiologists. In cases where conservative treatment is considered, it is critical to differentiate between inflammatory and noninflammatory appendicopathies due to the risk of severe complications in inflammatory cases. Imaging tests, particularly the periappendiceal fat stranding classification score, improve the risk prediction for recurrence following conservative treatment. According to previous studies, approximately 40% of patients receiving conservative treatment experience recurrence of AA. [ 1 , 2 , 3 , 36 , 37 , 40 ] As such, it is crucial to examine imaging findings when initially recommending conservative treatment and to correlate these findings with recurrence rates. The role of periappendiceal fat stranding in distinguishing between complicated and uncomplicated AA has been supported by prior studies. [ 35 , 36 , 41 ] The data of this study reinforce that higher fat stranding grades (2 and 3) are associated with inflammatory appendiceal diseases, while lower grades (0 and 1) are more commonly seen in noninflammatory appendiceal conditions, with high sensitivity and 100% specificity. This criterion is instrumental in achieving accurate diagnostic categorization and guiding clinical decision making for appropriate treatment. [ 17 , 38 , 42 ] This study had some limitations, the study was performed only on patients already chosen for an operation and did not consider patients who had abdominal pain but were treated without surgery. Based on the purpose of this study, correct diagnosis of the appendiceal disorder was pivotal to define the accuracy of the radiological sign. Given the limitations of this study, further research is needed to standardize clinical findings and surgical techniques in larger, more diverse populations. Such studies would further validate the degree of periappendiceal fat stranding as a routine assessment tool in deciding whether to proceed with appendectomies. CONCLUSION Periappendiceal fat stranding identified on computed tomography scans is efficacious in identifying appendicopathies and in the differential diagnosis of inflammatory and noninflammatory disorders. Declarations ETHICS APPROVAL AND CONSENT TO PARTICIPATE The study protocol was developed in accordance with the ethical guidelines stipulated in Resolution No. 466/2012 of the Brazilian National Health Council (Ministry of Health, Brazil, 2012) and was approved by the Research Ethics Committee (CAAE 51272121.2.0000.5175). Data collection began only after obtaining informed consent from patients participating in the study. Additionally, the project was registered on the Open Science Framework platform to enhance the methodology's replicability and integrity, under the digital object identifier https://doi.org/10.17605/OSF.IO/54ZF3. All patients were invited to participate in this study, and included only after they agreed and signed the Free and Informed Consent Term including the consent for publication. CONSENT FOR PUBLICATION All patients were invited to participate in this study, and included only after they agreed and signed the Free and Informed Consent Term including the consent for publication. All authors approved the final version of this manuscript and consent for publication of this article in the journal BMC Gastroenterology AVAILABILITY OF DATA AND MATERIALS The authors have full control of all data of this work, which are available for verification upon request. COMPETING AND CONFLICTING INTERESTS The authors declare no conflicting or competing interests with respect to the research, authorship and publication of this article. The authors have no financial relationship with any organization or institution. FUNDING This research and manuscript did not receive grants or financial support from funding agencies or institutions. AUTHORS’ CONTRIBUTIONS Ana Helena Leandro Cordeiro - was the radiologist who performed all exams of the patients and this study, she collected all data, performed the tomographic analyses and the statistical studies, and wrote the draft of the manuscript. Carlos Teixeira Brandt - participated from all steps of this work, participated of the surgeries included in this study, took responsibility for all aspects of this work and article, revised the manuscript and is responsible for the submission of this article for publication. Andy Petroianu - designed the study, participated from all steps of this work, wrote the draft of this manuscript, took responsibility for all aspects of this work and article, revised the manuscript and is responsible for the submission of this article for publication. ACKNOWLEDGMENTS The authors gratefully acknowledge all patients included in this study, and to the University Hospital of UNIFACISA for supporting us in data acquisition and preserving patient data confidentiality. The authors gratefully thank the Research Support Foundation of the State of Minas Gerais (FAPEMIG), the National Council for Scientific and Technological Development (CNPq) and the Dean’s Office for Post-graduate and Research (Pró-reitoria de Pós-graduação e Pesquisa) at UFMG for their financial support. References Di Saverio S, Podda M, De Simone B, et al. Diagnosis and treatment of acute appendicitis. World J Emerg Surg. 2020;15(1):27. 10.1186/s13017-020-00306-3 . 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A meta-analysis and trial sequential analysis comparing nonoperative versus operative management for uncomplicated appendicitis. World J Emerg Surg. 2024;19(1):2. 10.1186/s13017-023-00531-6 . Iamwat J, Teerasamit W, Apisarnthanarak P, Noppakunsomboon N, Kaewlai R. Predictive ability of CT findings in the differentiation of complicated and uncomplicated appendicitis. Insights Imaging. 2021;12(1):143. 10.1186/s13244-021-01086-3 . Mikwar Z, ALSaleh N, Hafez Mousa A, Alsuayri R. Role of preoperative computed tomography in the diagnosis of acute appendicitis and reduction of negative appendectomy rates. Ann Med Surg. 2022;77:103609. 10.1016/j.amsu.2022.103609 . Table 2 Table 2 is available in the Supplementary Files section. Additional Declarations No competing interests reported. Supplementary Files Table2.docx Cite Share Download PDF Status: Under Review Version 1 posted Reviewers invited by journal 02 Apr, 2026 Editor invited by journal 17 Feb, 2026 Editor assigned by journal 16 Feb, 2026 Submission checks completed at journal 16 Feb, 2026 First submitted to journal 15 Feb, 2026 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-8888276","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":617452638,"identity":"2c9900a8-270e-45f9-a7d4-ab0e3aba31be","order_by":0,"name":"Ana Helena Leandro Cordeiro","email":"","orcid":"","institution":"Universidade Federal de Minas Gerais","correspondingAuthor":false,"prefix":"","firstName":"Ana","middleName":"Helena Leandro","lastName":"Cordeiro","suffix":""},{"id":617452639,"identity":"3b27f21e-8e7d-4f91-ad26-dd42dae8c8a8","order_by":1,"name":"Carlos Teixeira Brandt","email":"","orcid":"","institution":"Universidade Federal de Minas Gerais","correspondingAuthor":false,"prefix":"","firstName":"Carlos","middleName":"Teixeira","lastName":"Brandt","suffix":""},{"id":617452640,"identity":"9275b66f-f49a-44cc-b723-a1093b081180","order_by":2,"name":"Andy Petroianu -","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzUlEQVRIiWNgGAWjYNACAwYGfhCdUECUcmaIFskGkBYDorWAdB2AWkcQmLP3H/vwocAuz/j86sQPDwwY5PnFDuDXYtlzmHnmDIPkYrMbbzdLAB1mOHN2An4tBjeSmZl5DJgTt904uwGkJcHgNiEt9x+DtNQnbp5xdvMP4rTcYAZpOZy4gb93G3G2WPYkGzPOMDieOOMG7zaLBAMJwn4xZz/4mOHDn+rE/v6zm2/+qLCR55cm5DA4SwKsUgK/clQt/AcIqx4Fo2AUjIKRCQDJLUIN+tneJQAAAABJRU5ErkJggg==","orcid":"","institution":"Universidade Federal de Minas Gerais","correspondingAuthor":true,"prefix":"","firstName":"Andy","middleName":"Petroianu","lastName":"-","suffix":""}],"badges":[],"createdAt":"2026-02-15 20:23:36","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8888276/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8888276/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":106405113,"identity":"1223ad06-2b2d-4553-8090-2c2b5fd18faf","added_by":"auto","created_at":"2026-04-08 09:21:52","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":521386,"visible":true,"origin":"","legend":"\u003cp\u003ePreoperative CT scans of patients diagnosed with acute appendicitis, showing the four degrees of periappendiceal fat stranding.\u003c/p\u003e\n\u003cp\u003eA - Grade 0 - cecal appendix within normal characteristics (*), and absence of periappendiceal fat stranding (arrow).\u003c/p\u003e\n\u003cp\u003eB - Grade 1 - appendix increased in diameter and length (*), with low periappendiceal fat stranding (arrow).\u003c/p\u003e\n\u003cp\u003eC - Grade 2 - appendix increased in diameter and length (*), with moderate periappendiceal fat stranding (arrows).\u003c/p\u003e\n\u003cp\u003eD - Grade 3 - appendix increased in diameter and length (*), with high periappendiceal fat stranding and reticular shape (arrows).\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8888276/v1/999dfbc60911fd691ffa2561.png"},{"id":106407091,"identity":"119d4f20-d988-41e8-8b4a-d09c590f82c1","added_by":"auto","created_at":"2026-04-08 09:35:22","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":960629,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8888276/v1/59cd4000-3723-4863-a845-5f0c428a7f7f.pdf"},{"id":106382703,"identity":"26ef5f77-1861-4e31-a232-57b74d396f6e","added_by":"auto","created_at":"2026-04-08 05:30:18","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":17681,"visible":true,"origin":"","legend":"","description":"","filename":"Table2.docx","url":"https://assets-eu.researchsquare.com/files/rs-8888276/v1/d7ba94d8ba1dfaa77825ea9e.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003ePeriappendiceal Fat Stranding as a Specific Tomographic Sign of Inflammatory and Noninflammatory Appendicopathies\u003c/p\u003e","fulltext":[{"header":"BACKGROUND","content":"\u003cp\u003eAcute appendicitis (AA) is the most common cause of acute abdomen requiring surgical treatment, accounting for 10% of hospital emergency care, and its complications are related to high morbidity and mortality. [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] AA has been diagnosed through the patient's clinical history, physical examination, laboratory tests, and imaging exams, in addition to clinical scores, developed with the aim of increasing the sensitivity and specificity of a precise diagnosis. [\u003cspan additionalcitationids=\"CR2 CR3 CR4 CR5 CR6 CR7 CR8 CR9 CR10 CR11\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eImaging exams in cases of patients with suspected AA increase the sensitivity, specificity and, above all, the accuracy of this diagnosis. Among these exams, ultrasound (US) [\u003cspan additionalcitationids=\"CR14 CR15 CR16 CR17 CR18 CR19 CR20 CR21\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e] and computed tomography (CT) are the most commonly used. CT signs of inflammatory and noninflammatory appendiceal disorders may increase specificity, although it still persists with a low sensitivity degree, with around 20% of morphologically normal appendices removal. [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] In this context, the degree of periappendiceal fat stranding has proven to be a relevant sign in the differentiation of inflammatory and noninflammatory forms of appendicopathies. [\u003cspan additionalcitationids=\"CR24 CR25 CR26 CR27 CR28 CR29 CR30 CR31 CR32 CR33\" citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eThe purpose of this study was to investigate the efficacy and clinical aspects associated with inflammatory appendicopathies and to verify the efficacy of the periappendiceal fat stranding in improving precise diagnosis of inflammatory and noninflammatory appendiceal disorders.\u003c/p\u003e"},{"header":"METHODS","content":"\u003cp\u003e The study protocol was developed in accordance with the ethical guidelines stipulated in Resolution No. 466/2012 of the Brazilian National Health Council (Ministry of Health, Brazil, 2012) and was approved by the Research Ethics Committee (CAAE 51272121.2.0000.5175). Data collection began only after obtaining informed consent from patients participating in the study. Additionally, The project was registered on the Open Science Framework platform to enhance the methodology's replicability and integrity, under the digital object identifier \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.17605/OSF.IO/54ZF3\u003c/span\u003e\u003cspan address=\"10.17605/OSF.IO/54ZF3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. All patients were invited to participate in this study, and included only after they agreed and signed the Free and Informed Consent Term including the consent for publication.\u003c/p\u003e \u003cp\u003eConsecutive adult (\u0026gt;\u0026thinsp;18 years old) patients who underwent appendectomy were invited to participate in this study. The selection process consisted of 200 patients, distributed in two groups based on postoperative histopathological diagnosis:\u003c/p\u003e \u003cp\u003e- inflammatory appendicopathy (n\u0026thinsp;=\u0026thinsp;175) and\u003c/p\u003e\n\u003cp\u003e- noninflammatory appendicopathy (n\u0026thinsp;=\u0026thinsp;25).\u003c/p\u003e\u003cp\u003eEligibility criteria required that participants have presented to the hospital with suspected appendiceal pain, completed all stages of the initial clinical examination, undergone abdominal computed tomography (CT), and subsequently undergone an appendectomy. Data collection started after participants signed the informed consent form.\u003c/p\u003e \u003cp\u003eAnamnesis, Alvarado scoring, and surgery were performed by hospital professionals without specific involvement in the research. Histopathological examinations were conducted by two pathologists to ensure accurate diagnosis of inflammatory versus noninflammatory cases. The CT images were reviewed by two radiologists.\u003c/p\u003e \u003cp\u003eHistopathological classification was based on the presence and severity of inflammation. Specimens were categorized as inflammatory appendicopathy if they exhibited diffuse lymphoplasmacytic infiltrate with neutrophil exudate dissociating the muscular and serosal layers and a fibrinoleukocytic crust indicative of ulcerophlegmonous 4 suppuration. In cases showing diffuse infiltration with neutrophils and cellular debris, perforation or necrosis was diagnosed. Noninflammatory appendicopathy was classified by the presence of lymphocyte infiltration, lymphoid hyperplasia, and wall edema with preserved appendiceal wall integrity.\u003c/p\u003e \u003cp\u003eRegarding CT findings, radiologists focused on the degree of periappendiceal fat stranding, applying precisely differential criteria outlined in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Radiologists were blinded to the histopathological outcomes of the resected appendices. Imaging was conducted on a Revolution Maxima CT scanner (GE Healthcare) with 64 channels and a 1.3 mm slice thickness. RadiAnt DICOM Viewer was used for image visualization.\u003c/p\u003e \u003cp\u003ePreoperative CT scans of patients diagnosed with acute appendicitis, show four degrees of periappendiceal fat stranding.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eA - Grade 0 - cecal appendix within normal characteristics (*), and absence of periappendiceal fat stranding (arrow).\u003c/p\u003e \u003cp\u003eB - Grade 1 - appendix increased in diameter and length (*), with low periappendiceal fat stranding (arrow).\u003c/p\u003e \u003cp\u003eC - Grade 2 - appendix increased in diameter and length (*), with moderate periappendiceal fat stranding (arrows).\u003c/p\u003e \u003cp\u003eD - Grade 3 - appendix increased in diameter and length (*), with high periappendiceal fat stranding and reticular shape (arrows).\u003c/p\u003e \u003cp\u003eFollowing data collection, information was organized in Excel 2019, and statistical analyses were performed using Jamovi (1.6.21) with the psychoPDA \u0026ndash; Psychometrics Post-Data Analysis package (1.0.5). Prevalence ratios with 95% confidence intervals were calculated to assess associations, with statistical significance defined as confidence intervals excluding 1.\u003c/p\u003e \u003cp\u003eFor association testing, fat stranding grades and Alvarado scores were dichotomized into high (grades 2 and 3 for fat stranding, related to scores 6 to 10 for Alvarado score) and low (grades 0 and 1 for fat stranding, related to scores 1 to 5 for Alvarado score). Group characteristics, such as age, hospital stay duration, and non-dichotomized Alvarado and fat stranding scores, were compared using the nonparametric Mann-Whitney test. Additionally, binomial regression analysis and ROC curve analysis were conducted to evaluate the diagnostic accuracy of the Alvarado score and periappendiceal fat stranding in relation to histopathological diagnosis, with inferential statistics considered significant at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e"},{"header":"RESULTS","content":"\u003cp\u003ePatients characteristics, including clinical data, complementary exam results, Alvarado scores, and degrees of periappendiceal fat stranding, are summarized in Table 1. The periappendiceal fat stranding scores observed on CT scans ranged from 0 to 3, with a mean score of 2.05 ± 0.87 for patients diagnosed with inflammatory appendicopathy and 0.40 ± 0.50 for those with noninflammatory appendicopathy. A statistically significant association was found between the degree of periappendiceal fat stranding and histopathological classification (p \u0026lt; 0.001). \u0026nbsp;\u003c/p\u003e\n\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv\u003eTable 1\u003c/div\u003e\n \u003cdiv\u003e\n \u003cp\u003e– Characteristics of patients operated on for acute appendicitis, their complementary exams, Alvarado score, and periappendiceal fat stranding criteria comparing distribution of histopathologic classification.\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003ePARAMETER\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003eAPPENDICOPATHY\u003c/p\u003e\n \u003cp\u003eInflammatory\u003c/p\u003e\n \u003cp\u003e(n = 175)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003eNoninflammatory\u003c/p\u003e\n \u003cp\u003e(n = 25)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eMale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003e103\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eFemale\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003e72\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eAge (years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003e32.9 ± 14.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e28.6 ± 10.1\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eFever\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003e57 (32.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e12 (48.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eLeukocytosis\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003e141 (80.6%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e15 (60.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eLeft turn\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003e84 (48.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e9 (36.0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eHospitalization priod\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003e1.75 ± 1.46\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e1.48 ± 0.82\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eAlvarado’s score\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003e7.58 ± 1.68\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e7.36 ± 1.82\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" colname=\"c1\"\u003e\n \u003cp\u003eDegree of stranding\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c2\"\u003e\n \u003cp\u003e2.05 ± 0.87***\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\" colname=\"c3\"\u003e\n \u003cp\u003e0.40 ± 0.50***\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eMean ± standard deviation of mean between groups; (%) = percentage of sample; *** = p \u0026lt; 0.001 (Mann-Whitney test).\u003c/p\u003e\n\u003cp\u003eGiven the cross-sectional design, a prevalence ratio analysis was conducted to examine associations between key variables and diagnostic accuracy for inflammatory versus noninflammatory cases. From the contingency table analysis presented in Table 2, histopathological classification was compared across variables such as sex, presence of leukocytosis, fever, left shift, degree of periappendiceal fat stranding, and Alvarado scores. In this study, no discrepancy occurred with the results of this parameter. A consensus was found in all included cases. The prevalence ratios with corresponding confidence intervals for these comparisons are present.\u003c/p\u003e \u003cp\u003eTo address the study's objective of supporting the diagnosis of appendiceal inflammation, the sensitivity and specificity of the degree of periappendiceal fat stranding. A strong predictive value of periappendiceal fat stranding, with grade 3 was identified as an optimal cut-off point, achieving 100% specificity and 74.86% sensitivity, with a positive predictive value of 100% and a negative predictive value of 36.23%. Patients with fat stranding grades of 2 to 3 (1.87, 95% confidence inervals) have a 1.57-fold higher prevalence ratio (PR) for an inflammatory profile compared to those with grades 0 and 1 (1.31, 95% confidence intervals). The PR of the other assessed parameters were not significant, as follows, sex (PR 1.10), leukocytosis (PR 1.17), fever (PR 1.09), left deviation (PR 1.06) and Alvarado score (PR 1.04).\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eThis study, included only medical records with complete and undisputed data, even though records were prepared by different surgeons. Given this selective criterion, discrepancies between findings of this study and those in similarly designed studies may arise. [\u003cspan additionalcitationids=\"CR36\" citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e] However, the thorough review of histopathological reports and tomographic image interpretations strengthens the reliability and standardization of the analyses of this work. Consequently, the findings regarding periappendiceal fat stranding serve as a dependable diagnostic criterion for AA.\u003c/p\u003e \u003cp\u003eThe clinical manifestations, complementary exams, and hospital stay duration observed in this study are consistent with existing literature on appendectomy patients. [\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e] However, it is noteworthy that the average age of patients with noninflammatory appendicopathy was lower than that of patients with appendicitis, although this difference was not significant. [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] The two groups compared in this study are uneven but the statistical results are reliable.\u003c/p\u003e \u003cp\u003eWhile the mean age of patients in this study aligns with reported data in the literature, the incidence of male patients was higher than that of females and exceeded expected proportions. [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e] Most clinical findings, including preoperative leukocytosis, also aligned with published data [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]. The incidence of pain upon sudden decompression at McBurney\u0026rsquo;s point diverged from the literature, although it is recognized that this sign can be absent in up to 70% of cases. [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eThe findings regarding the Alvarado score in diagnosing AA contrast with the literature. [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e] This study revealed that the Alvarado score lacks specificity and does not distinguish between inflammatory and noninflammatory appendicopathies. Therefore, the use of the Alvarado score in AA should be approached cautiously, especially given that it excludes imaging methods, which are the most sensitive and specific tools in diagnosing this condition.\u003c/p\u003e \u003cp\u003eThe semi-quantitative scoring of periappendiceal fat stranding observed via CT scans aids in differentiating inflammatory from noninflammatory appendiceal disorders more effectively. When combined with clinical findings and predictive risk scores, the degree of periappendiceal fat stranding enhances diagnostic accuracy, enabling a more precise assessment. [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e] This method demonstrates high clinical reliability.\u003c/p\u003e \u003cp\u003eAnother advantage of periappendiceal fat stranding classification through CT imaging is its objectivity, with no variance between radiologists\u0026rsquo; interpretations, which was easy and precisely defined. Routine application of this CT criterion may further reduce diagnostic inconsistencies among radiologists.\u003c/p\u003e \u003cp\u003eIn cases where conservative treatment is considered, it is critical to differentiate between inflammatory and noninflammatory appendicopathies due to the risk of severe complications in inflammatory cases. Imaging tests, particularly the periappendiceal fat stranding classification score, improve the risk prediction for recurrence following conservative treatment. According to previous studies, approximately 40% of patients receiving conservative treatment experience recurrence of AA. [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e] As such, it is crucial to examine imaging findings when initially recommending conservative treatment and to correlate these findings with recurrence rates.\u003c/p\u003e \u003cp\u003eThe role of periappendiceal fat stranding in distinguishing between complicated and uncomplicated AA has been supported by prior studies. [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e, \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e41\u003c/span\u003e] The data of this study reinforce that higher fat stranding grades (2 and 3) are associated with inflammatory appendiceal diseases, while lower grades (0 and 1) are more commonly seen in noninflammatory appendiceal conditions, with high sensitivity and 100% specificity. This criterion is instrumental in achieving accurate diagnostic categorization and guiding clinical decision making for appropriate treatment. [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e, \u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eThis study had some limitations, the study was performed only on patients already chosen for an operation and did not consider patients who had abdominal pain but were treated without surgery. Based on the purpose of this study, correct diagnosis of the appendiceal disorder was pivotal to define the accuracy of the radiological sign. Given the limitations of this study, further research is needed to standardize clinical findings and surgical techniques in larger, more diverse populations. Such studies would further validate the degree of periappendiceal fat stranding as a routine assessment tool in deciding whether to proceed with appendectomies.\u003c/p\u003e"},{"header":"CONCLUSION","content":"\u003cp\u003ePeriappendiceal fat stranding identified on computed tomography scans is efficacious in identifying appendicopathies and in the differential diagnosis of inflammatory and noninflammatory disorders.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eETHICS APPROVAL AND CONSENT TO PARTICIPATE\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study protocol was developed in accordance with the ethical guidelines stipulated in Resolution No. 466/2012 of the Brazilian National Health Council (Ministry of Health, Brazil, 2012) and was approved by the Research Ethics Committee (CAAE 51272121.2.0000.5175). Data collection began only after obtaining informed consent from patients participating in the study. Additionally, the project was registered on the Open Science Framework platform to enhance the methodology\u0026apos;s replicability and integrity, under the digital object identifier https://doi.org/10.17605/OSF.IO/54ZF3. All patients were invited to participate in this study, and included only after they agreed and signed the Free and Informed Consent Term including the consent for publication.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCONSENT FOR PUBLICATION\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll patients were invited to participate in this study, and included only after they agreed and signed the Free and Informed Consent Term including the consent for publication.\u003c/p\u003e\n\u003cp\u003eAll authors approved the final version of this manuscript and consent for publication of this article in the journal BMC Gastroenterology\u003c/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eAVAILABILITY OF DATA AND MATERIALS\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors have full control of all data of this work, which are available for verification upon request.\u003c/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eCOMPETING AND CONFLICTING INTERESTS\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no conflicting or competing interests with respect to the research, authorship and publication of this article. The authors have no financial relationship with any organization or institution.\u003c/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eFUNDING\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research and manuscript did not receive grants or financial support from funding agencies or institutions. \u003c/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eAUTHORS\u0026rsquo; CONTRIBUTIONS\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAna Helena Leandro Cordeiro - was the radiologist who performed all exams of the patients and this study, she collected all data, performed the tomographic analyses and the statistical studies, and wrote the draft of the manuscript.\u003c/p\u003e\n\u003cp\u003eCarlos Teixeira Brandt - participated from all steps of this work, participated of the surgeries included in this study, took responsibility for all aspects of this work and article, revised the manuscript and is responsible for the submission of this article for publication.\u003c/p\u003e\n\u003cp\u003eAndy Petroianu - designed the study, participated from all steps of this work, wrote the draft of this manuscript, took responsibility for all aspects of this work and article, revised the manuscript and is responsible for the submission of this article for publication. \u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eACKNOWLEDGMENTS\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors gratefully acknowledge all patients included in this study, and to the University Hospital of UNIFACISA for supporting us in data acquisition and preserving patient data confidentiality. The authors gratefully thank the Research Support Foundation of the State of Minas Gerais (FAPEMIG), the National Council for Scientific and Technological Development (CNPq) and the Dean\u0026rsquo;s Office for Post-graduate and Research (Pr\u0026oacute;-reitoria de P\u0026oacute;s-gradua\u0026ccedil;\u0026atilde;o e Pesquisa) at UFMG for their financial support.\u003c/p\u003e\n\n"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eDi Saverio S, Podda M, De Simone B, et al. Diagnosis and treatment of acute appendicitis. World J Emerg Surg. 2020;15(1):27. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s13017-020-00306-3\u003c/span\u003e\u003cspan address=\"10.1186/s13017-020-00306-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhang D, Wang S, Li H, Fu Z, Zhang J, Liu Z, Li S. 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Predictive ability of CT findings in the differentiation of complicated and uncomplicated appendicitis. Insights Imaging. 2021;12(1):143. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s13244-021-01086-3\u003c/span\u003e\u003cspan address=\"10.1186/s13244-021-01086-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMikwar Z, ALSaleh N, Hafez Mousa A, Alsuayri R. Role of preoperative computed tomography in the diagnosis of acute appendicitis and reduction of negative appendectomy rates. Ann Med Surg. 2022;77:103609. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.amsu.2022.103609\u003c/span\u003e\u003cspan address=\"10.1016/j.amsu.2022.103609\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"},{"header":"Table 2","content":"\u003cp\u003eTable 2 is available in the Supplementary Files section.\u003c/p\u003e\n"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"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":"bmc-gastroenterology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmge","sideBox":"Learn more about [BMC Gastroenterology](http://bmcgastroenterol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bmge/default.aspx","title":"BMC Gastroenterology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Appendicitis, Appendicopathy, Fat stranding, Histology, Computed tomography","lastPublishedDoi":"10.21203/rs.3.rs-8888276/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8888276/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cb\u003eBackground\u003c/b\u003e\u003c/p\u003e \u003cp\u003eAppendicopathies are still ongoing diagnostic challenges, with a rate of morphologically normal appendix removals exceeding 20% due to limitations of the diagnostic exams and scores. The objective of this study was to verify the efficacy of periappendiceal fat stranding identified on computed tomography as a complementary exam in differentiating appendicopathies, specifying inflammatory and noninflammatory disorders.\u003c/p\u003e\u003cp\u003e\u003cb\u003eMethods\u003c/b\u003e\u003c/p\u003e \u003cp\u003eA single-center, cross-sectional observational study was conducted on 200 consecutive patients of varying ages and both sexes submitted to appendectomy due to diagnosis of acute appendicitis. Medical records and imaging exams were assessed, including the Alvarado score and the periappendiceal fat stranding ranking level. This study compared inflammatory and noninflammatory appendicopathies. Statistical significance was set at p\u0026thinsp;\u0026lt;\u0026thinsp;0.05, with prevalence ratios calculated at a 95% CI and ROC curve analyses applied.\u003c/p\u003e\u003cp\u003e\u003cb\u003eResults\u003c/b\u003e\u003c/p\u003e \u003cp\u003eThe exams used in the Alvarado score failed in predicting appendiceal inflammation confirmed by the histopathologic exams. High periappendiceal fat stranding (grades 2 and 3) showed a prevalence ratio of 1.57 (95% CI: 1.31\u0026ndash;1.87). The ROC curve's area was 0.924, with grade 3 sensitivity at 74.86% and specificity at 100%, indicating strong predictive level.\u003c/p\u003e\u003cp\u003e\u003cb\u003eConclusion\u003c/b\u003e\u003c/p\u003e \u003cp\u003ePeriappendiceal fat stranding identified on computed tomography scans is efficacious in identifying appendicopathies and in the differential diagnosis of inflammatory and noninflammatory disorders.\u003c/p\u003e","manuscriptTitle":"Periappendiceal Fat Stranding as a Specific Tomographic Sign of Inflammatory and Noninflammatory Appendicopathies","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-08 05:30:14","doi":"10.21203/rs.3.rs-8888276/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewersInvited","content":"","date":"2026-04-02T05:45:25+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-02-17T07:23:24+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-02-17T04:54:20+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-02-17T04:52:24+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Gastroenterology","date":"2026-02-15T20:16:30+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-gastroenterology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bmge","sideBox":"Learn more about [BMC Gastroenterology](http://bmcgastroenterol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bmge/default.aspx","title":"BMC Gastroenterology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"36e21c96-fcf8-4278-9146-b1db7af6f317","owner":[],"postedDate":"April 8th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-08T05:30:14+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-08 05:30:14","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8888276","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8888276","identity":"rs-8888276","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}