Spectrum of computed tomography manifestations of appendiceal neoplasms: acute appendicitis and beyond.
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ABSTRACT:
SUBMITTER: Karande GY
PROVIDER: S-EPMC6482419 | biostudies-literature | 2019 Apr
REPOSITORIES: biostudies-literature
Publications
Spectrum of computed tomography manifestations of appendiceal neoplasms: acute appendicitis and beyond.
Karande Gita Yashwantrao GY Chua Wei Ming WM Yiin Raphael Shih Zhu RSZ Wong Kang Min KM Hedgire Sandeep S Tan Tien Jin TJ
Singapore medical journal 20190401 4
Appendiceal neoplasms are rare and often only discovered incidentally during surgery performed for acute appendicitis. Computed tomography (CT) has been demonstrated to be a reliable technique for accurately establishing the preoperative diagnosis of appendiceal neoplasms that manifest as acute appendicitis through the presence of certain imaging findings. Other manifestations of appendiceal neoplasms include appendiceal mass, mucocoele, localised abscess formation, ileus, increasing abdominal g ...[more]
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Project description:ObjectiveTo identify the CT findings associated with treatment failure after antibiotic therapy for acute appendicitis.Materials and methodsAltogether, 198 patients who received antibiotic therapy for appendicitis were identified by searching the hospital's surgery database. Selection criteria for antibiotic therapy were uncomplicated appendicitis with an appendiceal diameter equal to or less than 11 mm. The 86 patients included in the study were divided into a treatment success group and a treatment failure group. Treatment failure was defined as a resistance to antibiotic therapy or recurrent appendicitis during a 1-year follow-up period. Two radiologists independently evaluated the following CT findings: appendix-location, involved extent, maximal diameter, thickness, wall enhancement, focal wall defect, periappendiceal fat infiltration, and so on. For the quantitative analysis, two readers independently measured the CT values at the least attenuated wall of the appendix by drawing a round region of interest on the enhanced CT (HUpost) and non-enhanced CT (HUpre). The degree of appendiceal wall enhancement (HUsub) was calculated as the subtracted value between HUpost and HUpre. A logistic regression analysis was used to identify the CT findings associated with treatment failure.ResultsSixty-four of 86 (74.4%) patients were successfully treated with antibiotic therapy, with treatment failure occurring in the remaining 22 (25.5%). The treatment failure group showed a higher frequency of hypoenhancement of the appendiceal wall than the success group (31.8% vs. 7.8%; p = 0.005). Upon quantitative analysis, both HUpost (46.7 ± 21.3 HU vs. 58.9 ± 22.0 HU; p = 0.027) and HUsub (26.9 ± 17.3 HU vs. 35.4 ± 16.6 HU; p = 0.042) values were significantly lower in the treatment failure group than in the success group.ConclusionHypoenhancement of the appendiceal wall was significantly associated with treatment failure after antibiotic therapy for acute appendicitis.
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Project description:BackgroundUncomplicated and complicated acute appendicitis seem to be two different forms of this common abdominal emergency. The contribution of appendiceal microbiota to appendicitis pathogenesis has been suggested, but differences between uncomplicated and complicated appendicitis are largely unknown. We compared the appendiceal microbiota in uncomplicated and complicated acute appendicitis.MethodsThis prospective single-center clinical cohort study was conducted as part of larger multicenter MAPPAC trial enrolling adult patients with computed tomography or clinically confirmed uncomplicated or complicated acute appendicitis. The microbial composition of the appendiceal lumen was determined using 16S rRNA gene amplicon sequencing.ResultsBetween April 11, 2017, and March 29, 2019, 118 samples (41 uncomplicated and 77 complicated appendicitis) were available. After adjusting for age, sex, and BMI, alpha diversity in complicated appendicitis was higher (Shannon p = 0.011, Chao1 p = 0.006) compared to uncomplicated appendicitis. Microbial compositions were different between uncomplicated and complicated appendicitis (Bray-Curtis distance, P = 0.002). Species poor appendiceal microbiota composition with specific predominant bacteria was present in some patients regardless of appendicitis severity.ConclusionUncomplicated and complicated acute appendicitis have different appendiceal microbiome profiles further supporting the disconnection between these two different forms of acute appendicitis.Study registrationClinicalTrials.gov NCT03257423.
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Project description:BackgroundComputed tomography is widely used to diagnose acute appendicitis. Many adolescents and young adults are exposed to the associated radiation. A recent single-institution trial has reported promising results for low-dose computed tomography; however, this technique has not yet been widely adopted. LOCAT (low-dose computed tomography for appendicitis trial), a multi-institution randomized controlled non-inferiority trial, aims to compare low-dose computed tomography and standard-dose computed tomography as the first-line imaging tests for adolescents and young adults, and therefore to test the generalizability of the previous single-institution trial results.Methods/designParticipants with suspected appendicitis are randomly assigned to either the low-dose group (with a typical effective dose of 2 mSv) or the standard-dose group (as used in normal practice at each participating site, typically 8 mSv). The primary end point is the negative appendectomy rate (the percentage of the number of uninflamed appendices that were removed among all non-incidental appendectomies), which is a consequence of false-positive diagnoses, with a non-inferiority margin of 4.5 percentage points. The key secondary end point is the appendiceal perforation rate, which is a consequence of delayed (or false-negative) diagnoses. Participant recruitment will be continued until the number of non-incidental appendectomies for each group exceeds 444. The total number of expected participants approximates 3,000, including those not undergoing appendectomy.DiscussionIn addition to the study protocol, we elaborate on several challenging or potentially debatable components of the study design, including the broad eligibility criteria, choice of the primary end point, potential effect of using advanced imaging techniques on study results, determining and adjusting the radiation doses, ambiguities in reference standards, rationale for the non-inferiority margin, use of the intention-to-treat approach and difficulties in defining adverse events.Trial registrationClinicalTrials.gov NCT01925014.
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Project description:The molecular basis for the development of appendiceal mucinous tumours, which can be a cause of pseudomyxoma peritonei, remains largely unknown.Thirty-five appendiceal mucinous neoplasms were analysed for GNAS and KRAS mutations. A functional analysis of mutant GNAS was performed using a colorectal cancer cell line.A mutational analysis identified activating GNAS mutations in 16 of 32 low-grade appendiceal mucinous neoplasms (LAMNs) but in none of three mucinous adenocarcinomas (MACs). KRAS mutations were found in 30 LAMNs and in all MACs. We additionally analysed a total of 186 extra-appendiceal mucinous tumours and found that GNAS mutations were highly prevalent in intraductal papillary mucinous tumours of the pancreas (88%) but were rare or absent in mucinous tumours of the colorectum, ovary, lung and breast (0-9%). The prevalence of KRAS mutations was quite variable among the tumours. The introduction of the mutant GNAS into a colorectal cancer cell line markedly induced MUC2 and MUC5AC expression, but did not promote cell growth either in vitro or in vivo.Activating GNAS mutations are a frequent and characteristic genetic abnormality of LAMN. Mutant GNAS might play a direct role in the prominent mucin production that is a hallmark of LAMN.
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Project description:ObjectivesTo determine the prevalence of clinically relevant unrequested extra-cardiac imaging findings on cardiac Computed Tomography (CT) and explanatory factors thereof.MethodsA systematic review of studies drawn from online electronic databases followed by meta-analysis with meta-regression was performed. The prevalence of clinically relevant unrequested findings and potentially explanatory variables were extracted (proportion of smokers, mean age of patients, use of full FOV, proportion of men, years since publication).ResultsNineteen radiological studies comprising 12922 patients met the inclusion criteria. The pooled prevalence of clinically relevant unrequested findings was 13% (95% confidence interval 9-18, range: 3-39%). The large differences in prevalence observed were not explained by the predefined (potentially explanatory) variables.ConclusionsClinically relevant extra-cardiac findings are common in patients undergoing routine cardiac CT, and their prevalence differs substantially between studies. These differences may be due to unreported factors such as different definitions of clinical relevance and differences between populations. We present suggestions for basic reporting which may improve the interpretability and comparability of future research.
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Project description:IntroductionThe increasing incidence of acute appendicitis in sub-Saharan Africa emphasizes the need for accurate and reliable diagnostic tools. However, the variability in the diagnostic performance of computed tomography for suspected acute appendicitis coupled with comparatively higher negative appendectomy rates in this setting highlight a possible concern regarding the diagnostic accuracy. This study evaluated the diagnostic accuracy of a computed tomography scan for suspected acute appendicitis at the emergency department in Tanzania.MethodsA retrospective diagnostic accuracy study was conducted from July to October 2020. All patients above 14 years of age who presented at the emergency department with right iliac fossa abdominal pain of fewer than ten days and underwent computed tomography for suspected acute appendicitis were evaluated, and the Alvarado score was computed. Histological diagnosis and clinical follow-up of 14 days were considered the reference standard. Ethical clearance was sought from the Aga Khan University Ethical review committee.Results176 patients were included in this study. The sensitivity, specificity, and diagnostic accuracy were 100% (95% CI 91.8-100), 96.9% (95% CI 92.2-99.1), and 96.9% (95% CI 93.1-98.3), respectively. The mean Alvarado score in those without acute appendicitis was 4 (95% CI 3.7-4.3) compared to a mean score of 6.6 (95% CI 6.0-7.2) amongst those with acute appendicitis. The area under the receiver operator characteristics curve of computed tomography was 98.4%, and that of the Alvarado score was 84.1%.ConclusionsThe diagnostic performance of computed tomography in this study is similar to that established elsewhere. However, the Alvarado score is not routinely used for the initial screening of suspected acute appendicitis patients. A threshold of Alvarado score of 4 as a guide to conduct computed tomography for suspected acute appendicitis would have decreased computed tomography use by 50%, and missed 4 cases. Implementation studies that address Alvarado score use should be conducted.
| S-EPMC9612457 | biostudies-literature