A Systematic Review and Meta-Analysis of Diagnostic Performance of MRI for Evaluation of Acute Appendicitis

Acute abdomen in pediatric radiology

BACKGROUND

 Imaging is a common part of the workup for acute abdomen in childhood and adolescence. Rapid diagnosis is crucial for adequate therapy, especially in young children.

METHOD

 This review is intended to provide an overview of the typical causes of acute abdomen in children and adolescents and is specifically aimed at radiologists who do not regularly work in pediatric radiology.

RESULTS AND CONCLUSION

 Age-specific peculiarities make a division into three age groups useful: Newborns, infants and toddlers, and schoolchildren. Possible causes of acute abdomen in children range from congenital lesions, particularly in newborns, to entities well known in adult radiology, more commonly in school-aged children. Since younger children have a higher sensitivity to radiation and often a limited ability to cooperate, sonography and conventional X-ray are the primary imaging modalities used. Decisive advantages of sonography, especially in younger children, include its widespread availability, the lack of need for sedation, and the possibility of bedside examination. Supplementary cross-sectional imaging, usually MRI, is reserved for special clinical questions. Close interdisciplinary cooperation between attending clinicians and radiologists is essential for efficient diagnostics in this patient group.

KEY POINTS

  · Age-specific features must be observed. · Sonography and radiography are the most important modalities. · Both congenital and acquired pathologies play a role. · Good interdisciplinary cooperation is essential in this patient group.

CITATION FORMAT

· Lochbühler N, Bölle P, Müller-Abt P. Acute abdomen in pediatric radiology. Fortschr Röntgenstr 2024; 196: 451 - 462.

Referrals for Pediatric Appendicitis to a Tertiary Care Children's Hospital

OBJECTIVES

This study aimed to analyze pediatric referrals for definite or possible appendicitis, to compare clinical predictors and laboratory values between patients with and without a final diagnosis of appendicitis, and to determine the accuracy of prereferral diagnostic interpretations of computed tomography scans, ultrasound, and magnetic resonance imaging modalities.

METHODS

We conducted a retrospective analysis of pediatric patients referred from 2015 to 2019 to a tertiary care children's emergency department with definitive or possible appendicitis. Data abstracted included patient demographics, clinical symptoms, physical examination findings, laboratory results, and diagnostic imaging findings (by the referring center and the pediatric radiologist at the accepting center). An Alvarado and Appendicitis Inflammatory Response (AIR) score was calculated for each patient.

RESULTS

Analysis was performed on 381 patients; 226 (59%) had a final diagnosis of appendicitis. Patients with appendicitis were more likely to have symptoms of nausea ( P < 0.0001) and vomiting ( P < 0.0001), have a higher mean temperature ( P = 0.025), right lower quadrant abdominal pain to palpation ( P = <0.0001), rebound tenderness ( P < 0.0001), a higher mean Alvarado score [5.35 vs 3.45 ( P < 0.0001)], and a higher mean AIR score [4.02 vs 2.17 ( P < 0.0001)]. Of the 97 diagnostic images initially interpreted as appendicitis by the referring center, 10 (10.3%) were read as no evidence of appendicitis. Of the 62 diagnostic images initially interpreted as "possible appendicitis" by the referring center, 34 (54.8%) were read as no evidence of appendicitis. Of those diagnostic images initially interpreted as "appendicitis" or "possible appendicitis" by the referring center, 24/89 (27.0%) of computed tomography scans, 17/62 (27.4%) of ultrasounds, and 3/8 (37.5%) of magnetic resonance imaging results were read as no evidence of appendicitis.

CONCLUSIONS

Usage of established scoring algorithms, such as Alvarado and AIR, may decrease the unnecessary cost of diagnostic imaging and transfer to tertiary care. Virtual radiology consultations may be 1 potential solution to improve the referral process for pediatric appendicitis if initial interpretation is uncertain.

Comparison of the efficacy and safety of antibiotic treatment and appendectomy for acute uncomplicated appendicitis: a systematic review and meta-analysis

OBJECTIVE

This meta-analysis aimed to compare the efficacy and safety of antibiotic treatment and appendectomy for acute uncomplicated appendicitis.

METHODS

We searched the randomized controlled studies (RCTs) comparing appendectomy with antibiotic treatment for uncomplicated acute appendicitis in the electronic database including Pubmed, Embase, Cochrane, Web of Science, CNKI, VIP, and WanFang. The primary outcomes included complication-free treatment success at 1 year, complications, surgical complications, and the complicated appendicitis rates. Secondary outcomes included negative appendicitis, length of hospital stay, the quality of life at 1 month, and the impact of an appendicolith on antibiotic therapy.

RESULTS

Twelve randomized controlled studies were included. Compared with surgery group, the antibiotic group decreased the complication-free treatment success at 1 year (RR 0.81; 95% CI 0.73-0.91; z = 3.65; p = 0.000). Statistically significance was existed between antibiotic group and surgical group with both surgical types(open and laparoscopic) (RR 0.43; 95% CI 0.31-0.58; z = 5.36; p = 0.000), while no between the antibiotic treatment and laparoscopic surgery (RR 0.72; 95% CI 0.41-1.24; z = 1.19; p = 0.236). There was no statistically significant differences between two groups of surgical complications (RR 1.38; 95% CI 0.70-2.73; z = 0.93; p = 0.353), the complicated appendicitis rate (RR 0.71; 95% CI 0.36-1.42; z = 0.96; p = 0.338), negative appendectomy rate (RR 1.11; 95% CI 0.69-1.79; z = 0.43; p = 0.670), duration of hospital stay (SMD 0.08; 95%CI -0.11-0.27; z = 0.80; p = 0.422), and quality of life at 1 month (SMD 0.09; 95%CI -0.03-0.20; z = 1.53; p = 0.127). However, in the antibiotic treatment group, appendicolith rates were statistically higher in those whose symptoms did not improve (RR 2.94; 95% CI 1.28-6.74; z = 2.55; p = 0.011).

CONCLUSIONS

Although the cure rate of antibiotics is lower than surgery, antibiotic treatment is still a reasonable option for patients with uncomplicated acute appendicitis who do not want surgery without having to worry about complications or complicating the original illness.

Rapid MRI Abdomen for Assessment of Clinically Suspected Acute Appendicitis in the General Adult Population: a Systematic Review

OBJECTIVES

To perform a systematic review on the use of magnetic resonance imaging (MRI) of the abdomen to evaluate clinically suspected appendicitis in the general adult population. We examined the diagnostic accuracy, the reported trends of MRI use, and the factors that affect the utility of MRI abdomen, including study duration and cost-benefits.

METHODS

We conducted a systematic literature search on PubMed, MEDLINE, Embase, Web of Science, and Cochrane Library databases. We enrolled primary studies investigating the use of MRI in diagnosing appendicitis in the general adult population, excluding studies that predominantly reported on populations not representative of typical adult appendicitis presentations, such as those focusing on paediatric or pregnant populations.

RESULTS

Twenty-seven eligible primary studies and 6 secondary studies were included, totaling 2,044 patients from eight countries. The sensitivity and specificity of MRI for diagnosing appendicitis were 96% (95% CI: 93-97%) and 93% (95% CI: 80-98%), respectively. MRI can identify complicated appendicitis and accurately propose alternative diagnoses. The duration of MRI protocols in each primary study ranged between 2.26 and 30 minutes, and only one study used intravenous contrast agents in addition to the non-contrast sequences. Decision analysis suggests significant benefits for replacing computed tomography (CT) with MRI and a potential for cost reduction. Reported trends in MRI usage showed minimal utilisation in diagnostic settings even when MRI was available.

CONCLUSIONS

MRI accurately diagnoses appendicitis in the general adult population and improves the identification of complicated appendicitis or alternative diagnoses compared to other modalities using a single, rapid investigation.

Stump appendicitis in children: a systematic review

BACKGROUND

Stump appendicitis is a rare complication after primary appendectomy and is often not considered in the differential diagnosis of patients who have undergone an appendectomy. With this systematic review, the aim was to identify all cases of stump appendicitis in children in order to gain a better insight into the risk factors, clinical presentation, diagnostics, and treatment.

METHODS

Scopus and PubMed databases were searched. The search combinations used the following MeSH and free text terms: [(stump) OR (residual) OR (remaining) OR (retained) OR (recurrent)] AND (append*). Neither search filters nor text analysis tools were used. To be included, the report had to contain information about a patient between the age of 0 and 18 who was treated for stump appendicitis as a result of an inadequately performed appendectomy.

RESULTS

Out of the 19,976 articles, 29 of them, with a total of 34 cases, met the inclusion criteria. The mean age at the time of stump appendectomy was 13.32 ± 3.57 years, while the median time between primary and stump appendectomy was 7.5 (2.3 - 24.0) months. The ratio between boys and girls was 3.2: 1. Primary appendectomy was performed laparoscopically in a greater number of cases compared to the open approach (1.5: 1), and according to the available data, no higher proportion of complicated appendicitis was recorded during a primary appendectomy. The median duration of symptoms during stump appendicitis was 2 days, and in most cases, the pain was localized. Stump appendectomy in most cases was performed with an open approach, and in relation to the type of appendicitis, most of them were complicated. The mean value of the length of the stump was 2.79 ± 1.22 cm, and the smallest recorded length was 0.6 cm.

CONCLUSIONS

A non-specific clinical presentation with a history of appendectomy usually makes the diagnosis of stump appendicitis challenging for uninformed physicians, and due to untimely treatment, it usually results in complicated forms of stump appendicitis. Complete appendectomy remains the gold standard in the treatment of stump appendicitis.

How to Critically Appraise and Interpret Systematic Reviews and Meta-Analyses of Diagnostic Accuracy: A User Guide

Systematic reviews of diagnostic accuracy studies can provide the best available evidence to inform decisions regarding the use of a diagnostic test. In this guide, the authors provide a practical approach for clinicians to appraise diagnostic accuracy systematic reviews and apply their results to patient care. The first step is to identify an appropriate systematic review with a research question matching the clinical scenario. The user should evaluate the rigor of the review methods to evaluate its credibility (Did the review use clearly defined eligibility criteria, a comprehensive search strategy, structured data collection, risk of bias and applicability appraisal, and appropriate meta-analysis methods?). If the review is credible, the next step is to decide whether the diagnostic performance is adequate for clinical use (Do sensitivity and specificity estimates exceed the threshold that makes them useful in clinical practice? Are these estimates sufficiently precise? Is variability in the estimates of diagnostic accuracy across studies explained?). Diagnostic accuracy systematic reviews that are judged to be credible and provide diagnostic accuracy estimates with sufficient certainty and relevance are the most useful to inform patient care. This review discusses comparative, noncomparative, and emerging approaches to systematic reviews of diagnostic accuracy using a clinical scenario and examples based on recent publications.

Typical and Atypical Presentations of Appendicitis and Their Implications for Diagnosis and Treatment: A Literature Review

Appendicitis, an acute inflammation of the appendix, affects all demographic groups and exhibits various incidences and clinical manifestations. While acute appendicitis typically presents with colicky periumbilical abdominal pain that localizes to the right lower quadrant, atypical presentations are more common in children, geriatric, and pregnant patient populations, leading to delays in diagnosis. Clinical evaluation, clinical scoring systems, and inflammatory markers are commonly used, but their limitations have led to the increased use of diagnostic imaging in patients suspected of appendicitis. Acute appendicitis is managed by non-operative and operative management, depending on whether it is uncomplicated or complicated. Developing diagnostic pathways to improve outcomes and reduce complications is crucial. Although medical advancements have been made, diagnosing and managing appendicitis can be challenging, mainly when patients are present atypically. This literature review aims to comprehensively review typical and atypical presentations of appendicitis and their current implications for diagnosis and treatment modalities in pediatric, adult, pregnant, and geriatric patient populations.

A Review of Radiological Investigations in Cases of Acute Appendicitis in a Tertiary Care Hospital

INTRODUCTION

Acute appendicitis is the most common non-traumatic surgical emergency and early diagnosis and management are crucial to decrease morbidity and mortality. There is a variety of scoring systems and radiological investigations that have been used in the diagnosis of acute appendicitis. Hence, the aim of this study is to assess the diagnostic approach in patients with suspected appendicitis in a tertiary care hospital, focusing on the radiological burden.

METHODS

This is a cross-sectional study reviewing the electronic and manual medical records of all adult patients admitted with the diagnosis of acute appendicitis between January 2018 and December 2018 in Salmaniya Medical Complex, Manama, Bahrain. A review of the method of diagnosis (clinical, ultrasound, computed tomography, or others) was done, with a comparison to histopathological results in those that underwent surgical intervention to determine sensitivity and specificity.

RESULTS

In the study period, 488 patients were admitted with acute appendicitis; out of these, 461 underwent surgical intervention. A total of 66 CT scans and 148 ultrasounds were conducted for these patients, out of which 57% of ultrasounds and 86% of CT scans accurately diagnosed acute appendicitis based on histopathological diagnosis, resulting in a sensitivity of 65% and 92%, respectively, and a specificity of 56% and 25%, respectively.

CONCLUSION

The most accurate method of diagnosis of acute appendicitis (highest sensitivity) is CT scanning. However, a prospective study with a detailed assessment of complications of appendicitis is recommended.

MRI remains highly accurate in the diagnosis of appendicitis in pregnancy when read by radiologists of mixed specialty training and experience

PURPOSE

To audit the accuracy of magnetic resonance imaging (MRI) abdominal studies performed in the diagnosis of appendicitis in pregnant patients when read by radiologists of mixed experience.

METHODS

MRI reports from 45 pregnant women presenting to our emergency department for the investigation of appendicitis between 2009 and 2020 were retrospectively reviewed. Where available, these reports were correlated with surgical and pathology reports as well as follow-up clinical information. Following a review of literature, accuracy targets were set. Statistical analyses including sensitivity, specificity, positive, and negative predictive values were calculated.

RESULTS

A total of 18 radiology consultants read 45 MRI abdominal studies in the assessment of appendicitis during pregnancy with 62% (n = 28) of these read by specialist radiologists and the remainder by general radiologists. This yielded an accuracy in diagnosis of 99.8%, sensitivity of 80% (95% CI: 49-94.3%), and specificity of 100% (95% CI: 90-100%). The calculated negative predictive value was 94.6% (95% CI: 82.3-98.5%), and positive predictive value was 100% (95% CI: 90-100%). The appendix was not identified in 19 patients (42%). A statistically significant relationship between the presence of right iliac fossa stranding of the fat OR free fluid was associated with appendicitis (p = 0.01). Alternate diagnoses were identified in 8% (n = 4) of cases.

CONCLUSION

MRI is a highly accurate imaging modality for the assessment of appendicitis in pregnancy. Even with variable reader MRI experience, MRI demonstrates an accuracy of 99.8% and a positive predictive value for acute appendicitis of 100%. Double reading and the possible inclusion of DWI may help further improve accuracy and minimise false-negative rates.

Diagnostic value of 3D T1-weighted gradient-echo and 2D T1-weighted in-phase and out-of-phase gradient-echo sequences for appendicitis diagnosis in pregnant women

Objectives

This study compared the diagnostic value of 3D T1-weighted (T1W) gradient-echo (GRE) and 2D T1W in-phase and out-of-phase GRE sequences for appendicitis diagnosis in pregnant women.

Material and Methods

This retrospective study included 25 pregnant patients with suspected appendicitis who underwent 1.5 Tesla abdominal magnetic resonance imaging and had definitive diagnoses. Four doctors approached four separate imaging groups: A (only T2-weighted image [T2WI] sequences), B (T2WI and 3D T1W GRE sequences), C (T2WI and T1W in-phase and out-of-phase GRE sequences), and D (T2WI, 3D T1W GRE, and T1W in-phase and out-of-phase GRE sequences). The kappa (κ) index was used to compare the appendicitis diagnostic results between groups. The diagnostic value of these sequences in the diagnosis of pregnancy appendicitis was also evaluated.

Results

Groups A and C had average consistency with definitive diagnosis (κ = 0.6), lower than Groups B and D (κ = 0.865), indicating a high definite diagnosis consistency. Groups B and D had similarly high sensitivity (80%), specificity (100%), positive predictive value (100%), negative predictive value (95.2%), and accuracy (ACC) (96%), higher than Groups A and C (60%, 95%, 75%, 90.5%, and 88%, respectively).

Conclusion

3D T1W-GRE sequences improve appendicitis diagnosis in pregnancy compared to T2W sequences alone. Adding in and out phase GRE sequences do not increase diagnostic ACC.

The role of magnetic resonance imaging in acute abdominal pain in paediatric age group

Background

The purpose of this study is to evaluate the utility of magnetic resonance imaging in the assessment of acute atraumatic abdominal pain as the first line cross sectional modality in children, so as to prevent excessive radiation exposure from computed tomography scan and to review the magnetic resonance imaging features of common acute abdominal and pelvic conditions.

Results

30 patients (0–18 years) underwent rapid unenhanced magnetic resonance imaging. The results of our study indicated that for the diagnosis of causes for acute abdominal pain, magnetic resonance imaging had sensitivity of 92% (95% confidence interval 73.8–97.6%) and a specificity of 80% (95% confidence interval 28.4–99.5%). The positive predictive value was 95.8% (95% confidence interval 79.9–99.3%) and negative predictive value was 67% (95% confidence interval 33.1–89.0%) which had a highly significant statistical association (p < 0.001).

Conclusion

Unenhanced magnetic resonance imaging is an excellent option for the initial, detailed evaluation of acute abdominal emergencies in pediatric patients because it can diagnose the whole range of presenting abnormalities which include the causes of abdominal pain warranting surgical and nonsurgical management.

ACR Appropriateness Criteria® Right Lower Quadrant Pain: 2022 Update

This document focuses on imaging in the adult and pregnant populations with right lower quadrant (RLQ) abdominal pain, including patients with fever and leukocytosis. Appendicitis remains the most common surgical pathology responsible for RLQ abdominal pain in the United States. Other causes of RLQ pain include right colonic diverticulitis, ureteral stone, and infectious enterocolitis. Appropriate imaging in the diagnosis of appendicitis has resulted in decreased negative appendectomy rate from as high as 25% to approximately 1% to 3%. Contrast-enhanced CT remains the primary and most appropriate imaging modality to evaluate this patient population. MRI is approaching CT in sensitivity and specificity as this technology becomes more widely available and utilization increases. Unenhanced MRI and ultrasound remain the diagnostic procedures of choice in the pregnant patient. MRI and ultrasound continue to perform best in the hands of the experts. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer-reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer-reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Pediatric Emergency MRI

There is an overall increase in the use of imaging in the pediatric emergency room setting, which is accompanied by a reduction in computed tomography examinations performed mainly due to the increased awareness of the risks of ionizing radiation. Advances in MRI technology have led to shortened scan time, decreased motion sensitivity, and improved spatial resolution. With increased access to MRI in the emergency room setting, the goal of this article is to review major applications of MR in pediatric emergency room patients.

MRI as First Line Imaging for Suspected Acute Appendicitis during Pregnancy: Diagnostic Accuracy and level of Inter-Radiologist Agreement

OBJECTIVE

Evaluation of acute appendicitis (AA) in pregnancy is supported with diagnostic imaging. Typically, ultrasound (US) is performed first, and then often followed by magnetic resonance imaging (MRI) due to continued diagnostic uncertainty. The purpose of our study was to evaluate the sensitivity, specificity, and accuracy of US as compared to MRI and to evaluate the inter-radiologist agreement amongst body Radiologists with varying levels of expertise.

MATERIALS AND METHODS

We performed a retrospective study of 364 consecutive pregnant patients with clinical suspicion of AA at a single center over a 6-year period. Sensitivity, Specificity, accuracy, positive and negative predictive values were calculated for US and MRI. Inter Radiologist agreement was determined using Cohen's Kappa analysis between original interpreting Radiologist and retrospective review by expert Radiologist.

RESULTS

Thirty-one of 364 patients (8.5%) underwent appendectomy based on preoperative diagnosis, with confirmation of acute appendicitis (AA) by pathology in 19. US was able to visualize the appendix in only 6 (1.65%), 5 of whom had appendicitis. 141 patients underwent MRI, and correctly diagnosed appendicitis in 9. No patient with a negative MRI diagnosis had AA. The sensitivity, and negative predictive value for diagnosing AA with MRI was 100%. The MRI inter-reader agreement for appendix visualization and overall accuracy were 87.9 and 98% with Cohen Kappa of 0.7 and 0.56 respectively.

CONCLUSIONS

Our data suggests that MRI should be considered the first line imaging modality in pregnant patients suspected of having AA. Body Radiologists with varied levels of experience in MRI readouts had substantial agreement.

Magnetic Resonance Imaging Availability Reduces Computed Tomography Use for Pediatric Appendicitis Diagnosis

OBJECTIVES

To determine if introducing magnetic resonance imaging (MRI) as an imaging option for children with suspected appendicitis and an inconclusive ultrasound reduces computed tomography (CT) use.

METHODS

This is a retrospective cohort study of patients aged 5 to 18 years who presented to a pediatric emergency department (ED) with suspected appendicitis. Rates of CT use 1 year before and 1 year after MRI availability are compared. Secondary outcomes include missed and negative appendectomies, imaging charges, time to antibiotics and surgery, time to radiology read, ED length of stay, and test characteristics of MRI and CT.

RESULTS

Of the 981 patients screened, 499 patients met inclusion criteria. There was an absolute reduction of CT use of 25% from 38% in year 1 to 13% in year 2 (95% confidence interval, 18% to 33%). Advanced imaging charges were $371 higher in year 2 (MRI) than year 1 (CT), and median time to radiologist reads was longer in MRIs than CTs (129 versus 62 minutes; difference 53 minutes, 95% confidence interval, 23 to 74 minutes). All other secondary outcomes, including ED length of stay and test characteristics, were statistically similar.

CONCLUSIONS

Introducing MRI for as an imaging option for children with suspected appendicitis and an inconclusive ultrasound markedly reduced CT use, but did result in a small increase in imaging charges and time to preliminary radiology read.

Low-Dose Abdominal CT for Evaluating Suspected Appendicitis in Adolescents and Young Adults: Review of Evidence

Due to its excellent diagnostic performance, CT is the mainstay of diagnostic test in adults with suspected acute appendicitis in many countries. Although debatable, extensive epidemiological studies have suggested that CT radiation is carcinogenic, at least in children and adolescents. Setting aside the debate over the carcinogenic risk of CT radiation, the value of judicious use of CT radiation cannot be overstated for the diagnosis of appendicitis, considering that appendicitis is a very common disease, and that the vast majority of patients with suspected acute appendicitis are adolescents and young adults with average life expectancies. Given the accumulated evidence justifying the use of low-dose CT (LDCT) of only 2 mSv, there is no reasonable basis to insist on using radiation dose of multi-purpose abdominal CT for the diagnosis of appendicitis, particularly in adolescents and young adults. Published data strongly suggest that LDCT is comparable to conventional dose CT in terms of clinical outcomes and diagnostic performance. In this narrative review, we will discuss such evidence for reducing CT radiation in adolescents and young adults with suspected appendicitis.

Magnetic resonance imaging (MRI) for diagnosis of acute appendicitis

BACKGROUND

Appendicitis remains a difficult disease to diagnose, and imaging adjuncts are commonly employed. Magnetic resonance imaging (MRI) is an imaging test that can be used to diagnose appendicitis. It is not commonly regarded as a first-line imaging test for appendicitis, but the reported diagnostic accuracy in some studies is equivalent to computed tomography (CT) scans. As it does not expose patients to radiation, it is an attractive imaging modality, particularly in women and children.

OBJECTIVES

The primary objective was to determine the diagnostic accuracy of MRI for detecting appendicitis in all patients. Secondary objectives: To investigate the accuracy of MRI in subgroups of pregnant women, children, and adults. To investigate the potential influence of MRI scanning variables such as sequences, slice thickness, or field of view.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and Embase until February 2021. We searched the references of included studies and other systematic reviews to identify further studies. We did not exclude studies that were unpublished, published in another language, or retrospective.

SELECTION CRITERIA

We included studies that compared the outcome of an MRI scan for suspected appendicitis with a reference standard of histology, intraoperative findings, or clinical follow-up. Three study team members independently filtered search results for eligible studies.

DATA COLLECTION AND ANALYSIS

We independently extracted study data and assessed study quality using the Quality Assessment of Studies of Diagnostic Accuracy - Revised (QUADAS-2) tool. We used the bivariate model to calculate pooled estimates of sensitivity and specificity.

MAIN RESULTS

We identified 58 studies with sufficient data for meta-analysis including a total of 7462 participants (1980 with and 5482 without acute appendicitis). Estimates of sensitivity ranged from 0.18 to 1.0; estimates of specificity ranged from 0.4 to 1.0. Summary sensitivity was 0.95 (95% confidence interval (CI) 0.94 to 0.97); summary specificity was 0.96 (95% CI 0.95 to 0.97). Sensitivity and specificity remained high on subgroup analysis for pregnant women (sensitivity 0.96 (95% CI 0.88 to 0.99); specificity 0.97 (95% CI 0.95 to 0.98); 21 studies, 2282 women); children (sensitivity 0.96 (95% CI 0.95 to 0.97); specificity 0.96 (95% CI 0.92 to 0.98); 17 studies, 2794 children); and adults (sensitivity 0.96 (95% CI 0.93 to 0.97); specificity 0.93 (95% CI 0.80 to 0.98); 9 studies, 1088 participants), as well as different scanning techniques. In a hypothetical cohort of 1000 patients, there would be 12 false-positive results and 30 false-negative results. Methodological quality of the included studies was poor, and the risk of bias was high or unclear in 53% to 83% of the QUADAS-2 domains.

AUTHORS' CONCLUSIONS

MRI appears to be highly accurate in confirming and excluding acute appendicitis in adults, children, and pregnant women regardless of protocol. The methodological quality of the included studies was generally low due to incomplete and low standards of follow-up, so summary estimates of sensitivity and specificity may be biased. We could not assess the impact and direction of potential bias given the very low number of high-quality studies. Studies comparing MRI protocols were few, and although we found no influence of MRI protocol variables on the summary estimates of accuracy, our results do not rule out that some MRI protocols are more accurate than others.

Abbreviated MRI in patients with suspected acute appendicitis in emergency: a prospective study

PURPOSE

To determine the diagnostic performance of an abbreviated non-contrast MRI protocol in diagnosing acute appendicitis.

METHODS

Prospectively, a total of 67 consenting consecutive patients with clinical suspicion of acute appendicitis (Alvarado score ≥ 5) were evaluated with an abbreviated three-sequence non-contrast MRI protocol (axial T2WI, coronal T2WI, axial DWI) at a single tertiary care center. MRI was interpreted by two radiologists blinded to the clinical details, other investigations, and outcome of the patients. Diagnostic performance of MRI was determined using either histopathological examination (HPE) results as the reference standard in surgical cases (n = 39), or final clinical diagnosis at discharge and 3-months follow-up in non-operatively managed cases (n = 28).

RESULTS

Sixty-seven patients comprising 42 males, 25 females including 1 pregnant patient were enrolled (median age 24 years; age range 6-70 years). The median acquisition duration of the MRI protocol was 12.5 min. In the analysis of the complete cohort including both surgical and non-operatively managed cases (n = 67), MRI showed sensitivity of 93.3% (95% CI 81.7-98.6%), specificity of 86.4% (95% CI 65.1-97.1%), and diagnostic accuracy of 91.0% (95% CI 81.5-96.6%) (p < 0.001). In the subset of surgical cases with HPE as the reference standard (n = 39), MRI showed sensitivity of 97.1% (95% CI 84.7-99.9%), specificity of 100% (95% CI 47.8-100%), and diagnostic accuracy of 98% (95% CI 87.5-100%) (p < 0.001).

CONCLUSION

MRI may be performed to diagnose acute appendicitis or alternative causes of right iliac fossa pain. An abbreviated MRI protocol consisting of only three sequences without IV contrast, patient preparation, or antiperistaltic agents could shorten the examination duration while retaining diagnostic accuracy.

WSES/GAIS/SIS-E/WSIS/AAST global clinical pathways for patients with intra-abdominal infections

Intra-abdominal infections (IAIs) are common surgical emergencies and have been reported as major contributors to non-trauma deaths in hospitals worldwide. The cornerstones of effective treatment of IAIs include early recognition, adequate source control, appropriate antimicrobial therapy, and prompt physiologic stabilization using a critical care environment, combined with an optimal surgical approach. Together, the World Society of Emergency Surgery (WSES), the Global Alliance for Infections in Surgery (GAIS), the Surgical Infection Society-Europe (SIS-E), the World Surgical Infection Society (WSIS), and the American Association for the Surgery of Trauma (AAST) have jointly completed an international multi-society document in order to facilitate clinical management of patients with IAIs worldwide building evidence-based clinical pathways for the most common IAIs. An extensive non-systematic review was conducted using the PubMed and MEDLINE databases, limited to the English language. The resulting information was shared by an international task force from 46 countries with different clinical backgrounds. The aim of the document is to promote global standards of care in IAIs providing guidance to clinicians by describing reasonable approaches to the management of IAIs.

Comparison of MRI appendix biometrics in children with and without acute appendicitis

OBJECTIVES

The goal of this study is to improve MRI-specific diagnostic criteria for pediatric appendicitis through comparison of normal and abnormal appendix-related imaging features.

METHODS

A retrospective multireader-multicase design was used, including non-contrast MRI performed for suspected pediatric appendicitis following non-diagnostic US from January 2014 to December 2017. Positive diagnosis was defined by surgical pathology or symptom resolution after antibiotics. Four pediatric radiologists independently graded study biometrics while blinded to clinical data. Balanced complete block design was used to determine performance characteristics.

RESULTS

Global diagnosis of appendicitis (208 studies) had sensitivity 90.6% and specificity 97.7%. Median appendix diameter was 10.4 mm among positive cases and 5.8 mm among negative cases (p < 0.001) with an optimal diagnostic cutoff of 7.5 mm (sensitivity 89.4%, specificity 86.5%). Median appendix wall thickness was 2.6 mm among positive cases and 1.7 mm among negative cases (p < 0.001) with an optimal diagnostic cutoff of 2.3 mm (sensitivity 63.1%, specificity 82.9%). Performance characteristics for qualitative appendix features included distinguishable appendix luminal signal (sensitivity 89.6%, specificity 83.7%), intraluminal fluid-signal intensity (sensitivity 63.6%; specificity 52.3%), intraluminal signal intermediate between fluid and bowel wall (sensitivity 91.0%; specificity 37.1%), appendicolith (sensitivity 34.9%; specificity 100.0%), intraluminal layering (sensitivity 25.9%; specificity 100.0%), hyperintense appendix wall signal (sensitivity 31.7%; specificity 100.0%), periappendiceal fluid (sensitivity 66.8%; specificity 72.5%), periappendiceal fatty edema (sensitivity 91.3%; specificity 94.5%), and free pelvic fluid (sensitivity 88.5%; specificity 26.0).

CONCLUSIONS

This study provides MRI-specific performance of pediatric appendicitis quantitative and qualitative biometrics with peri-appendiceal fatty edema, appendix diameter > 7.5 mm, and distinguishable appendix luminal signal demonstrating the highest overall accuracy.

KEY POINTS

• This retrospective multireader-multicase study characterized magnetic resonance imaging-specific diagnostic accuracy of quantitative and qualitative biometrics for pediatric appendicitis. • The optimal quantitative diagnostic thresholds for an abnormal pediatric appendix at MRI included diameter and wall thickness of 7.5 mm and 2.3 mm, respectively. • Qualitative imaging biometrics with high specificity for pediatric appendicitis on MRI included the presence of distinguishable appendix lumen signal from wall signal, appendicolith, intraluminal fluid-fluid layer, appendix wall hyperintensity, and peri-appendiceal fatty edema.

Acute appendicitis and pregnancy: diagnostic performance of magnetic resonance imaging

BACKGROUND

The aim of this study was to evaluate the performance of magnetic resonance imaging (MRI) in the diagnosis of acute appendicitis in pregnant women.

METHODS

The study was conducted in 2 referral centers in Brussels, Belgium, between March 1st 2009 and January 31st 2017. Pregnant women who presented with abdominal pain and underwent MRI were included. Baseline characteristics, clinical, laboratory, and ultrasound test results were extracted retrospectively from the electronic medical charts. MRI exams were prospectively reevaluated by an experienced radiologist blinded to patient outcome and MRI findings. Visualization of the appendix and assessment of gastrointestinal, genitourinary, and vascular systems were recorded. The diagnosis of acute appendicitis was confirmed by pathology exam.

RESULTS

In total, 85 patients were included. The appendix was identified in all patients on MRI and acute appendicitis was suspected in 7. The diagnosis was confirmed in 6 patients. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of MRI were 100% (95% confidence interval [95% CI]: 54.1%-100%), 98.7% (95% CI: 93.2-99.9%), 85.7% (95% CI: 46.1-97.7%), and 100%, respectively. In contrast, the sensitivity, specificity, PPV, and NPV of the combination of clinical exam, laboratory findings and/or ultrasound were 100% (95% CI: 54.1%-100%), 62% (95% CI: 50.4-72.7%), 16.7% (95% CI: 13.1-20.96%), and 100%, respectively.

CONCLUSION

MRI is reliable in confirming or excluding acute appendicitis during pregnancy, with a rate of visualization of the appendix approaching 100%. Efforts should be focused on the implementation of MRI as a first-line imaging exam in the workup of suspected acute appendicitis during pregnancy.

Abdominal fellowship-trained versus generalist radiologist accuracy when interpreting MR and CT for the diagnosis of appendicitis

OBJECTIVES

To compare the diagnostic accuracy of generalist radiologists working in a community setting against abdominal radiologists working in an academic setting for the interpretation of MR when diagnosing acute appendicitis among emergency department patients.

METHODS

This observational study examined MR image interpretation (non-contrast MR with diffusion-weighted imaging and intravenous contrast-enhanced MR) from a prospectively enrolled cohort at an academic hospital over 18 months. Eligible patients had an abdominopelvic CT ordered to evaluate for appendicitis and were > 11 years old. The reference standard was a combination of surgery and pathology results, phone follow-up, and chart review. Six radiologists blinded to clinical information, three each from community and academic practices, independently interpreted MR and CT images in random order. We calculated test characteristics for both individual and group (consensus) diagnostic accuracy then performed Chi-square tests to identify any differences between the subgroups.

RESULTS

Analysis included 198 patients (114 women) with a mean age of 31.6 years and an appendicitis prevalence of 32.3%. For generalist radiologists, the sensitivity and specificity (95% confidence interval) were 93.8% (84.6-98.0%) and 88.8% (82.2-93.2%) for MR and 96.9% (88.7-99.8%) and 91.8% (85.8-95.5%) for CT. For fellowship-trained radiologists, the sensitivity and specificity were 96.9% (88.2-99.5%) and 89.6% (82.8-94%) for MR and 98.4% (90.5-99.9%) and 93.3% (87.3-96.7%) for CT. No statistically significant differences were detected between radiologist groups (p = 1.0, p = 0.53, respectively) or when comparing MR to CT (p = 0.21, p = 0.17, respectively).

CONCLUSIONS

MR is a reliable, radiation-free imaging alternative to CT for the evaluation of appendicitis in community-based generalist radiology practices.

KEY POINTS

• There was no significant difference in MR image interpretation accuracy between generalist and abdominal fellowship-trained radiologists when evaluating sensitivity (p = 1.0) and specificity (p = 0.53). • There was no significant difference in accuracy comparing MR to CT imaging for diagnosing appendicitis for either sensitivity (p = 0.21) or specificity (p = 0.17). • With experience, generalist radiologists enhanced their MR interpretation accuracy as demonstrated by improved interpretation sensitivity (OR 2.89 CI 1.44-5.77, p = 0.003) and decreased mean interpretation time (5 to 3.89 min).

Adult appendicitis: Clinical practice guidelines from the French Society of Digestive Surgery and the Society of Abdominal and Digestive Imaging

INTRODUCTION

The French Society of Digestive Surgery (SFCD) and the Society of Abdominal and Digestive Imaging (SIAD) have collaborated to propose recommendations for clinical practice in the management of adult appendicitis.

METHODS

An analysis of the literature was carried out according to the methodology of the French National Authority for Health (HAS). A selection was performed from collected references and then a manual review of the references listed in the selected articles was made in search of additional relevant articles. The research was limited to articles whose language of publication was English or French. Articles focusing on the pediatric population were excluded. Based on the literature review, the working group proposed recommendations whenever possible. These recommendations were reviewed and approved by a committee of experts.

RESULTS

Recommendations about appendicitis in adult patients were proposed with regard to clinical, laboratory and radiological diagnostic modalities, treatment strategy for uncomplicated and complicated appendicitis, surgical technique, and specificities in the case of macroscopically healthy appendix, terminal ileitis and appendicitis in the elderly and in pregnant women.

CONCLUSION

These recommendations for clinical practice may be useful to the surgeon in optimizing the management of acute appendicitis in adults.

Role of MRI in the Evaluation of Thoracoabdominal Emergencies

Thoracic and abdominal pathology are common in the emergency setting. Although computed tomography is preferred in many clinical situations, magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) have emerged as powerful techniques that often play a complementary role to computed tomography or may have a primary role in selected patient populations in which radiation is of specific concern or intravenous iodinated contrast is contraindicated. This review will highlight the role of MRI and MRA in the emergent imaging of thoracoabdominal pathology, specifically covering acute aortic pathology (acute aortic syndrome, aortic aneurysm, and aortitis), pulmonary embolism, gastrointestinal conditions such as appendicitis and Crohn disease, pancreatic and hepatobiliary disease (pancreatitis, choledocholithiasis, cholecystitis, and liver abscess), and genitourinary pathology (urolithiasis and pyelonephritis). In each section, we will highlight the specific role for MRI, discuss basic imaging protocols, and illustrate the MRI features of commonly encountered thoracoabdominal pathology.

Diagnosis of Uncomplicated and Complicated Appendicitis in Adults

Background:

Diagnostic work-up of acute appendicitis remains challenging. While some guidelines advise to use a risk stratification based on clinical parameters, others use standard imaging in all patients. As non-operative management of uncomplicated appendicitis has been identified as feasible and safe, differentiation between uncomplicated and complicated appendicitis is of paramount importance. We reviewed the literature to describe the optimal strategy for diagnosis of acute appendicitis.

Methods:

A narrative review about the diagnosis of acute appendicitis in adult patients was conducted. Both diagnostic strategies and goals were analyzed.

Results:

For diagnosing acute appendicitis, both ruling in and ruling out the disease are important. Clinical and laboratory findings individually do not suffice, but when combined in a diagnostic score, a better risk prediction can be made for having acute appendicitis. However, for accurate diagnosis imaging seems obligatory in patients suspected for acute appendicitis. Scoring systems combining clinical and imaging features may differentiate between uncomplicated and complicated appendicitis and may enable ruling out complicated appendicitis. Within conservatively treated patients with uncomplicated appendicitis, predictive factors for non-responsiveness to antibiotics and recurrence of appendicitis need to be defined in order to optimize treatment outcomes.

Conclusion:

Standard imaging increases the diagnostic power for both ruling in and ruling out acute appendicitis. Incorporating imaging features in clinical scoring models may provide better differentiation between uncomplicated and complicated appendicitis. Optimizing patient selection for antibiotic treatment of appendicitis may minimize recurrence rates, resulting in better treatment outcomes.

Performance of overnight on-call radiology residents in interpreting unenhanced abdominopelvic magnetic resonance imaging studies performed for pediatric right lower quadrant abdominal pain

BACKGROUND

Abdominopelvic magnetic resonance imaging (MRI) is increasingly being used to evaluate children with abdominal pain suspected of having acute appendicitis. At our institution, these examinations are preliminarily interpreted by radiology residents, especially when performed after hours.

OBJECTIVE

To determine the accuracy of preliminary reports rendered by radiology residents in this setting.

MATERIALS AND METHODS

Three hundred seventy-seven pediatric abdominopelvic MRI examinations were included. The preliminary (resident) and final (attending) radiology reports were coded as diagnosing acute appendicitis or no acute appendicitis. The concordance between resident and attending radiologist interpretations was calculated. Additionally, both resident and attending reports were compared to available surgical pathology or clinical follow-up data.

RESULTS

Overall concordance rate for the diagnosis of acute appendicitis was 97.1%. Concordance for verified cases of acute appendicitis was 93.4%. Concordance rates did not differ by residents' postgraduate year levels. When compared against surgical pathology or clinical follow-up data, residents demonstrated 91.2% sensitivity and 97.6% specificity. There was no statistically significant difference in the sensitivity or specificity of resident or attending radiologist interpretations.

CONCLUSION

Radiology residents demonstrate high concordance with attending pediatric radiologists in their interpretations of pediatric abdominopelvic MRI for acute appendicitis. The diagnostic performances of residents and attendings were comparable.

Discriminating complicated from uncomplicated appendicitis by ultrasound imaging, computed tomography or magnetic resonance imaging: systematic review and meta-analysis of diagnostic accuracy

Background

Discriminating complicated from uncomplicated appendicitis is crucial. Patients with suspected complicated appendicitis are best treated by emergency surgery, whereas those with uncomplicated appendicitis may be treated with antibiotics alone. This study aimed to obtain summary estimates of the accuracy of ultrasound imaging, CT and MRI in discriminating complicated from uncomplicated appendicitis

Methods

A systematic literature review was conducted by an electronic search in PubMed, Embase and the Cochrane Library for studies describing the diagnostic accuracy of complicated versus uncomplicated appendicitis. Studies were included if the population comprised adults, and surgery or pathology was used as a reference standard. Risk of bias and applicability were assessed with QUADAS-2. Bivariable logitnormal random-effect models were used to estimate mean sensitivity and specificity.

Results

Two studies reporting on ultrasound imaging, 11 studies on CT, one on MRI, and one on ultrasonography with conditional CT were included. Summary estimates for sensitivity and specificity in detecting complicated appendicitis could be calculated only for CT, because of lack of data for the other imaging modalities. For CT, mean sensitivity was 78 (95 per cent c.i. 64 to 88) per cent, and mean specificity was 91 (85 to 99) per cent. At a median prevalence of 25 per cent, the positive predictive value of CT for complicated appendicitis would be 74 per cent and its negative predictive value 93 per cent.

Conclusion

Ultrasound imaging, CT and MRI have limitations in discriminating between complicated and uncomplicated appendicitis. Although CT has far from perfect sensitivity, its negative predictive value for complicated appendicitis is high.

The diagnostic accuracy of ultrasound in the diagnosis of acute appendicitis in pregnancy

Objective: Clinically suspected appendicitis is the most common nonobstetric surgical problem encountered in pregnancy. The diagnosis of appendicitis is hampered by equivocal symptoms during pregnancy. Ultrasonography (US) remains, as a rule, the imaging test of choice for the diagnosis of clinically suspected appendicitis during pregnancy and other imaging tools such as computed tomography (CT) or magnetic resonance imaging (MRI) are usually avoided. We evaluated the accuracy of US in the diagnosis of appendicitis during pregnancy.Methods: The clinical and sonographic findings of all pregnant women (n = 90), who underwent appendectomy between January 2005 and December 2017 at our institution, were retrospectively reviewed, analyzed, and compared to the clinical and sonographic findings similarly obtained for a control group of nonpregnant women matched for age and date of surgery (±6 months). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of ultrasonic findings were calculated and compared between groups as well as within the three pregnancy trimesters.Results: The mean age of the patients was 31.3 ± 0.4. Right lower quadrant pain was present in almost all patients (99%). The sole imaging modality used in our study cohort was US. Among nonpregnant controls, CT scan was primarily used on more occasions (53.3%) compared to US (45.6%). Nonpregnant women underwent significantly more laparoscopies compared to pregnant women (83.3 versus 45.6%, p < .001). The rate of negative appendectomy was higher in pregnant women (31.1 versus 10%, p = .002). Among pregnant women operated there was a higher rate of inconclusive or negative imaging (43.3 versus 11.1%, p < .001). The rate of perforated appendix at surgery was similar in both groups (6.7 and 4.4%, respectively, p = .75).Conclusions: Ultrasonography (US) is of mediocre accuracy for the diagnosis of acute appendicitis in pregnant patients beyond the first trimester of pregnancy. Thirty percent of pregnant women with suspected appendicitis are futilely operated. Given the low yield of US, a second-line imaging should be considered in cases of inconclusive US before surgery.

Unenhanced MRI of the Abdomen and Pelvis in the Comprehensive Evaluation of Acute Atraumatic Abdominal Pain in Children

OBJECTIVE. The purpose of this study is to show the utility of rapid unenhanced MRI in the comprehensive assessment of acute atraumatic abdominal pain in children, including appendicitis and alternate diagnoses, and to review the MRI features of common acute abdominal and pelvic conditions in a large, single-institution cohort. CONCLUSION. Rapid unenhanced MRI is an excellent option for the initial, comprehensive evaluation of acute abdominal emergencies in pediatric patients because it can diagnose the full range of presenting abnormalities, including causes of abdominal pain warranting surgical and nonsurgical management.

ACR Appropriateness Criteria® Suspected Appendicitis-Child

Acute appendicitis represents the most common abdominal surgical urgency/emergency in children. Imaging remains a central tool in the diagnosis of acute appendicitis and has been shown to facilitate management and decrease the rate of negative appendectomies. The initial consideration for imaging in a child with suspected acute appendicitis is based on clinical assessment, which can be facilitated with published scoring systems. The level of clinical risk (low, intermediate, high) and the clinical scenario (suspicion for complication) define the need for imaging and the optimal imaging modality. In some situations, no imaging is required, while in others ultrasound, CT, or MRI may be appropriate. This review frames the presentation of suspected acute appendicitis in terms of the clinical risk and also discusses the unique situations of the equivocal or nondiagnostic initial ultrasound examination and suspected appendicitis with suspicion for complication (eg, bowel obstruction). The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Acute Appendicitis Review: Background, Epidemiology, Diagnosis, and Treatment

Appendicitis is a common occurrence in both the adult and pediatric populations. The condition most commonly occurs between the ages of 10 and 20 years with a lifetime risk of 8.6% and 6.7% for males and females respectively. Its diagnosis focuses on clinical presentation and imaging modalities classified according to scoring systems such as the Alvarado scoring system. A number of imaging modalities can be used, with CT being the most common one. For acute appendicitis, surgical intervention is considered to be the gold standard of treatment. However, recent research has focused on other modalities of treatment including antibiotics and endoscopic retrograde appendicitis therapy (ERAT) to avoid surgical complications.

Is the platelet to lymphocyte ratio a promising biomarker to distinguish acute appendicitis? Evidence from a systematic review with meta-analysis

Background

Although several previous studies have examined the association between the platelet to lymphocyte ratio (PLR) and acute appendicitis (AA), findings have been controversial. We aimed to systematically assess the available evidence to elucidate the overall relationship between the PLR and AA.

Methods

Pubmed and Embase databases were searched for all available published literature before August, 2019 by two independent investigators for observational studies reporting the association between the PLR and AA. Random effects models were applied for all meta-analyses. Pooled standardized mean difference (SMD) and 95% confidence interval (CI) were calculated as effect estimates.

Results

Eleven articles met the inclusion criteria and included in this study. Meta-analysis showed that the level of PLR in the AA group was significantly higher than that in the control group (SMD: 1.19, 95% CI: 0.75 to 1.62, P<0.001). A series of subgroup analyses were conducted to investigate the heterogeneity, showing a significant increase in PLV levels in adults with age ≥30 years (SMD: 1.46, 95% CI: 0.89 to 2.02),compared to those in adult <30 years(SMD: 0.58, 95% CI: 0.12 to 1.04) or in children (SMD: 1.03, 95% CI: 0.51 to 1.56). Compared to non-AA controls, a significant increased PLR level was also observed in non-perforated AA (SMD: 1.23, 95% CI: 0.88 to 1.59) and in AA patients during pregnancy (SMD: 0.70, 95% CI: 0.36 to 1.04), while not in perforated AA (SMD: 2.28, 95% CI: -1.72 to 6.28).

Conclusions

A significant increase in PLR level is found in patients with AA, indicating that PLR is a promising biomarker for AA. PLR provides a convenient option for emergency department to quickly screen for clinically or radiologically confirmed AA awaiting appendectomy, especially for pregnant women suspected of having AA. More high-quality evidence is needed to further confirm the diagnostic accuracy of PLR for AA.

[Antibiotics alone as an alternative to appendectomy for uncomplicated acute appendicitis in adults: Changes in treatment modalities related to the COVID-19 health crisis]

La saturation intrahospitalière liée à l’arrivée massive de patients atteints du COVID-19 nécessitant une prise en charge urgente conduit à reconsidérer la prise en charge des autres patients. Différer au maximum les hospitalisations et les opérations chirurgicales non urgentes est un des objectifs des chirurgiens afin de désengorger autant que possible le système de soins. Alors que la majorité des opérations programmées sont annulées, la réduction de la chirurgie d’urgence est évidemment compliquée à proposer sans altérer la qualité de la prise en charge et conduire à une perte de chance pour le patient. Cependant, l’appendicite aiguë constitue une situation spécifique bien particulière et la fréquence de cette pathologie conduit à considérer ce cas particulier. En effet, tandis que le traitement recommandé de l’appendicite aiguë non compliquée est chirurgical, l’alternative non chirurgicale par antibiothérapie seule a été largement évaluée dans la littérature au cours de travaux de qualité. Dans la mesure où la limite principale du traitement médical exclusif de l’appendicite aiguë non compliquée est le risque de récidive à distance, cette option thérapeutique représente une alternative de choix pour réduire la surcharge intrahospitalière dans ce contexte de crise sanitaire. L’objectif de ce travail est donc de mettre à disposition des médecins et des chirurgiens un guide pratique issu d’une analyse de la littérature sur le traitement médical de l’appendicite aiguë non compliquée de l’adulte afin de pouvoir proposer ce traitement alternatif aux bons patients et dans des bonnes conditions, notamment lorsque l’accès au bloc opératoire est impossible.

Antibiotics alone as an alternative to appendectomy for uncomplicated acute appendicitis in adults: Changes in treatment modalities related to the COVID-19 health crisis

The massive inflow of patients with COVID-19 requiring urgent care has overloaded hospitals in France and impacts the management of other patients. Deferring hospitalization and non-urgent surgeries has become a priority for surgeons today in order to relieve the health care system. It is obviously not simple to reduce emergency surgery without altering the quality of care or leading to a loss of chance for the patient. Acute appendicitis is a very specific situation and the prevalence of this disease leads us to reconsider this particular disease in the context of the COVID-19 crisis. Indeed, while the currently recommended treatment for uncomplicated acute appendicitis is surgical appendectomy, the non-surgical alternative of medical management by antibiotic therapy alone has been widely evaluated by high-quality studies in the literature. Insofar as the main limitation of exclusively medical treatment of uncomplicated acute appendicitis is the risk of recurrent appendicitis, this treatment option represents an alternative of choice to reduce the intra-hospital overload in this context of health crisis. The aim of this work is therefore to provide physicians and surgeons with a practical guide based on a review of the literature on the medical treatment of uncomplicated acute appendicitis in adults, to offer this alternative treatment to the right patients and under good conditions, especially when access to the operating room is limited or impossible.

Diagnosis and treatment of acute appendicitis: 2020 update of the WSES Jerusalem guidelines

BACKGROUND AND AIMS

Acute appendicitis (AA) is among the most common causes of acute abdominal pain. Diagnosis of AA is still challenging and some controversies on its management are still present among different settings and practice patterns worldwide. In July 2015, the World Society of Emergency Surgery (WSES) organized in Jerusalem the first consensus conference on the diagnosis and treatment of AA in adult patients with the intention of producing evidence-based guidelines. An updated consensus conference took place in Nijemegen in June 2019 and the guidelines have now been updated in order to provide evidence-based statements and recommendations in keeping with varying clinical practice: use of clinical scores and imaging in diagnosing AA, indications and timing for surgery, use of non-operative management and antibiotics, laparoscopy and surgical techniques, intra-operative scoring, and peri-operative antibiotic therapy.

METHODS

This executive manuscript summarizes the WSES guidelines for the diagnosis and treatment of AA. Literature search has been updated up to 2019 and statements and recommendations have been developed according to the GRADE methodology. The statements were voted, eventually modified, and finally approved by the participants to the consensus conference and by the board of co-authors, using a Delphi methodology for voting whenever there was controversy on a statement or a recommendation. Several tables highlighting the research topics and questions, search syntaxes, and the statements and the WSES evidence-based recommendations are provided. Finally, two different practical clinical algorithms are provided in the form of a flow chart for both adults and pediatric (< 16 years old) patients.

CONCLUSIONS

The 2020 WSES guidelines on AA aim to provide updated evidence-based statements and recommendations on each of the following topics: (1) diagnosis, (2) non-operative management for uncomplicated AA, (3) timing of appendectomy and in-hospital delay, (4) surgical treatment, (5) intra-operative grading of AA, (6) ,management of perforated AA with phlegmon or abscess, and (7) peri-operative antibiotic therapy.

Appendicitis risk prediction models in children presenting with right iliac fossa pain (RIFT study): a prospective, multicentre validation study

BACKGROUND

Acute appendicitis is the most common surgical emergency in children. Differentiation of acute appendicitis from conditions that do not require operative management can be challenging in children. This study aimed to identify the optimum risk prediction model to stratify acute appendicitis risk in children.

METHODS

We did a rapid review to identify acute appendicitis risk prediction models. A prospective, multicentre cohort study was then done to evaluate performance of these models. Children (aged 5-15 years) presenting with acute right iliac fossa pain in the UK and Ireland were included. For each model, score cutoff thresholds were systematically varied to identify the best achievable specificity while maintaining a failure rate (ie, proportion of patients identified as low risk who had acute appendicitis) less than 5%. The normal appendicectomy rate was the proportion of resected appendixes found to be normal on histopathological examination.

FINDINGS

15 risk prediction models were identified that could be assessed. The cohort study enrolled 1827 children from 139 centres, of whom 630 (34·5%) underwent appendicectomy. The normal appendicectomy rate was 15·9% (100 of 630 patients). The Shera score was the best performing model, with an area under the curve of 0·84 (95% CI 0·82-0·86). Applying score cutoffs of 3 points or lower for children aged 5-10 years and girls aged 11-15 years, and 2 points or lower for boys aged 11-15 years, the failure rate was 3·3% (95% CI 2·0-5·2; 18 of 539 patients), specificity was 44·3% (95% CI 41·4-47·2; 521 of 1176), and positive predictive value was 41·4% (38·5-44·4; 463 of 1118). Positive predictive value for the Shera score with a cutoff of 6 points or lower (72·6%, 67·4-77·4) was similar to that of ultrasound scan (75·0%, 65·3-83·1).

INTERPRETATION

The Shera score has the potential to identify a large group of children at low risk of acute appendicitis who could be considered for early discharge. Risk scoring does not identify children who should proceed directly to surgery. Medium-risk and high-risk children should undergo routine preoperative ultrasound imaging by operators trained to assess for acute appendicitis, and MRI or low-dose CT if uncertainty remains.

FUNDING

None.

Cost Comparison of Ultrasound Versus MRI to Diagnose Adolescent Female Patients Presenting with Acute Abdominal/Pelvic Pain Using Time-Driven Activity-Based Costing

RATIONALE AND OBJECTIVES

To compare the cost of ultrasound (US) versus magnetic resonance imaging (MRI) using time-driven activity-based costing in adolescent female patients with suspected appendicitis.

MATERIALS AND METHODS

Process maps were created using data from electronic medical record review and patient shadowing for adolescent female patients undergoing US or noncontrast MRI exams of the abdomen and pelvis for suspected appendicitis. Capacity cost rates for all personnel, equipment, facilities, and supplies in each exam pathway were established from institutional accounting data. The cost of each process step was determined by multiplying step-specific capacity cost rates by the mean time required to complete the step. Total pathway costs for US and MRI were computed by summing the costs of all steps through each pathway, and a direct cost comparison was made between the two modalities.

RESULTS

Process maps for US and MRI pathways were generated from 231 and 52 patient encounters, respectively. Patients undergoing US exams followed one of six pathways depending on exam order (abdomen versus pelvis performed first) and whether additional time was needed for bladder filling. Mean total US pathway time was 91 minutes longer than for MRI (US = 166 minutes; MRI = 75 minutes). Total MRI pathway cost was $209.97 compared to a mean US cost of $258.33 (range = $163.21-$293.24).

CONCLUSION

MRI can be a faster and less costly alternative to US for evaluating suspected appendicitis in adolescent female patients. While precise costs will vary by institution, MRI may be a viable and at times preferable alternative to US in this patient population.

Computed tomography for diagnosis of acute appendicitis in adults

BACKGROUND

Diagnosing acute appendicitis (appendicitis) based on clinical evaluation, blood testing, and urinalysis can be difficult. Therefore, in persons with suspected appendicitis, abdominopelvic computed tomography (CT) is often used as an add-on test following the initial evaluation to reduce remaining diagnostic uncertainty. The aim of using CT is to assist the clinician in discriminating between persons who need surgery with appendicectomy and persons who do not.

OBJECTIVES

Primary objective Our primary objective was to evaluate the accuracy of CT for diagnosing appendicitis in adults with suspected appendicitis. Secondary objectives Our secondary objectives were to compare the accuracy of contrast-enhanced versus non-contrast-enhanced CT, to compare the accuracy of low-dose versus standard-dose CT, and to explore the influence of CT-scanner generation, radiologist experience, degree of clinical suspicion of appendicitis, and aspects of methodological quality on diagnostic accuracy.

SEARCH METHODS

We searched MEDLINE, Embase, and Science Citation Index until 16 June 2017. We also searched references lists. We did not exclude studies on the basis of language or publication status.

SELECTION CRITERIA

We included prospective studies that compared results of CT versus outcomes of a reference standard in adults (> 14 years of age) with suspected appendicitis. We excluded studies recruiting only pregnant women; studies in persons with abdominal pain at any location and with no particular suspicion of appendicitis; studies in which all participants had undergone ultrasonography (US) before CT and the decision to perform CT depended on the US outcome; studies using a case-control design; studies with fewer than 10 participants; and studies that did not report the numbers of true-positives, false-positives, false-negatives, and true-negatives. Two review authors independently screened and selected studies for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently collected the data from each study and evaluated methodological quality according to the Quality Assessment of Studies of Diagnostic Accuracy - Revised (QUADAS-2) tool. We used the bivariate random-effects model to obtain summary estimates of sensitivity and specificity.

MAIN RESULTS

We identified 64 studies including 71 separate study populations with a total of 10,280 participants (4583 with and 5697 without acute appendicitis). Estimates of sensitivity ranged from 0.72 to 1.0 and estimates of specificity ranged from 0.5 to 1.0 across the 71 study populations. Summary sensitivity was 0.95 (95% confidence interval (CI) 0.93 to 0.96), and summary specificity was 0.94 (95% CI 0.92 to 0.95). At the median prevalence of appendicitis (0.43), the probability of having appendicitis following a positive CT result was 0.92 (95% CI 0.90 to 0.94), and the probability of having appendicitis following a negative CT result was 0.04 (95% CI 0.03 to 0.05). In subgroup analyses according to contrast enhancement, summary sensitivity was higher for CT with intravenous contrast (0.96, 95% CI 0.92 to 0.98), CT with rectal contrast (0.97, 95% CI 0.93 to 0.99), and CT with intravenous and oral contrast enhancement (0.96, 95% CI 0.93 to 0.98) than for unenhanced CT (0.91, 95% CI 0.87 to 0.93). Summary sensitivity of CT with oral contrast enhancement (0.89, 95% CI 0.81 to 0.94) and unenhanced CT was similar. Results show practically no differences in summary specificity, which varied from 0.93 (95% CI 0.90 to 0.95) to 0.95 (95% CI 0.90 to 0.98) between subgroups. Summary sensitivity for low-dose CT (0.94, 95% 0.90 to 0.97) was similar to summary sensitivity for standard-dose or unspecified-dose CT (0.95, 95% 0.93 to 0.96); summary specificity did not differ between low-dose and standard-dose or unspecified-dose CT. No studies had high methodological quality as evaluated by the QUADAS-2 tool. Major methodological problems were poor reference standards and partial verification primarily due to inadequate and incomplete follow-up in persons who did not have surgery.

AUTHORS' CONCLUSIONS

The sensitivity and specificity of CT for diagnosing appendicitis in adults are high. Unenhanced standard-dose CT appears to have lower sensitivity than standard-dose CT with intravenous, rectal, or oral and intravenous contrast enhancement. Use of different types of contrast enhancement or no enhancement does not appear to affect specificity. Differences in sensitivity and specificity between low-dose and standard-dose CT appear to be negligible. The results of this review should be interpreted with caution for two reasons. First, these results are based on studies of low methodological quality. Second, the comparisons between types of contrast enhancement and radiation dose may be unreliable because they are based on indirect comparisons that may be confounded by other factors.

Nonfetal Imaging During Pregnancy: Acute Abdomen/Pelvis

Abdominal pain is a common occurrence in pregnant women and may have a variety of causes, including those that are specific to pregnancy (eg, round ligament pain in the first trimester) and the wide range of causes of abdominal pain that affect men and women who are not pregnant (eg, appendicitis, acute cholecystitis). Noncontrast magnetic resonance (MR) imaging is increasingly performed to evaluate pregnant women with abdominal pain, either as the first-line test or as a second test following ultrasonography. The imaging appearance of causes of abdominal pain in pregnant women are reviewed with an emphasis on noncontrast MR imaging.

The Pooled Diagnostic Accuracy of Neuroimaging, General Movements, and Neurological Examination for Diagnosing Cerebral Palsy Early in High-Risk Infants: A Case Control Study

Introduction: Clinical guidelines recommend using neuroimaging, Prechtls’ General Movements Assessment (GMA), and Hammersmith Infant Neurological Examination (HINE) to diagnose cerebral palsy (CP) in infancy. Previous studies provided excellent sensitivity and specificity for each test in isolation, but no study has examined the pooled predictive power for early diagnosis. Methods: We performed a retrospective case-control study of 441 high-risk infants born between 2003 and 2014, from three Italian hospitals. Infants with either a normal outcome, mild disability, or CP at two years, were matched for birth year, gender, and gestational age. Three-month HINE, GMA, and neuroimaging were retrieved from medical records. Logistic regression was conducted with log-likelihood and used to determine the model fit and Area Under the Curve (AUC) for accuracy. Results: Sensitivity and specificity for detecting CP were 88% and 62% for three-month HINE, 95% and 97% for absent fidgety GMs, and 79% and 99% for neuroimaging. The combined predictive power of all three assessments gave sensitivity and specificity values of 97.86% and 99.22% (PPV 98.56%, NPV 98.84%). Conclusion: CP can be accurately detected in high-risk infants when these test findings triangulate. Clinical implementation of these tools is likely to reduce the average age when CP is diagnosed, and intervention is started.

Sepsis in Pregnancy: Recognition and Resuscitation

The normal physiologic changes of pregnancy complicate evaluation for sepsis and subsequent management. Previous sepsis studies have specifically excluded pregnant patients. This narrative review evaluates the presentation, scoring systems for risk stratification, diagnosis, and management of sepsis in pregnancy. Sepsis is potentially fatal, but literature for the evaluation and treatment of this condition in pregnancy is scarce. While the definition and considerations of sepsis have changed with large, randomized controlled trials, pregnancy has consistently been among the exclusion criteria. The two pregnancy-specific sepsis scoring systems, the modified obstetric early warning scoring system (MOEWS) and Sepsis in Obstetrics Score (SOS), present a number of limitations for application in the emergency department (ED) setting. Methods of generation and subsequently limited validation leave significant gaps in identification of septic pregnant patients. Management requires consideration of a variety of sources in the septic pregnant patient. The underlying physiologic nature of pregnancy also highlights the need to individualize resuscitation and critical care efforts in this unique patient population. Pregnant septic patients require specific considerations and treatment goals to provide optimal care for this particular population. Guidelines and scoring systems currently exist, but further studies are required.

Pregnancy and appendicitis: a systematic review and meta-analysis on the clinical use of MRI in diagnosis of appendicitis in pregnant women

Background

The aim of this systematic review and meta-analysis was to evaluate the clinical use of MRI for the evaluation of acute appendicitis during pregnancy.

Methods

The searches were conducted by two independent researchers (MK, MS) to find the relevant studies published from 1/1/2009 until end of 30/12/2018. We searched for published literature in the English language in MEDLINE via PubMed, EMBASETM via Ovid, The Cochrane Library, and Trip database. For literature published in other languages, we searched national databases (Magiran and SID), KoreaMed, and LILACS. The keywords used in the search strategy are Pregnancy [MeSH], Pregnant [MeSH] OR-Magnetic resonance imaging [MeSH] OR-Appendicitis [MeSH] OR-Ultrasound, [MeSH] OR, imaging, MRI [MeSH] OR"،" and Right lower quadrant pain [MeSH]. The risk of bias of every article was evaluated by using QUADAS-2. On the basis of the results from the 2 × 2 tables, pooled measures for sensitivity, specificity, diagnostic odds ratio (DOR), and area under the curves (AUC) along with their 95% confidence intervals (CIs) were calculated using the DerSimonian Lair methodology.

Results

As many as 1164 studies were selected. After analyzing the correspondence of the studies with the required criteria, 19 studies were selected for the final review. For appendicitis in pregnancy, the MRI sensitivity was 91.8% at the 95% confidence interval of (95% CI 87.7-94.9%). At the confidence interval of 95%, the specificity was 97.9% (95% CI 0.97.2-100%). The risk of bias in the studies conducted was measured using the QUADAS-2 tool.

Conclusion

MRI has high sensitivity and specificity (91.8%, 97.9% respectively) for the diagnosis of acute appendicitis in pregnant patients with clinically suspected appendicitis. It is an excellent imaging technique in many instances, which does not expose a fetus, or the mother, to ionizing radiation, making it an excellent option for pregnant patients with suspected acute appendicitis.

Absolute neutrophil count as a diagnostic guide for the use of MRI in the workup of suspected appendicitis in children

BACKGROUND/PURPOSE

To assess the additive value of magnetic resonance imaging (MRI) in the setting of an equivocal US (Eq-US) with or without an elevated absolute neutrophil count (ANC).

METHODS

Single-institution, retrospective review of children ages 5-18 years who presented to the ER with suspected appendicitis from 9/2015 to 8/2016. US, ANC, and MRI results were reviewed. Imaging was identified as positive/suspicious, normal, or equivocal and ANC <8000/mm³ was defined as normal.

RESULTS

738 patients with a median age of 11 years (IQR 8-14) met inclusion criteria. US was equivocal in 61.4%. Among 304 (67.1%) patients with an Eq-US and normal ANC, only 5 (1.6%) had acute appendicitis. In contrast, 28 of 149 patients (18.8%) with Eq-US and elevated ANC had appendicitis. MRI was performed in 125 patients with Eq-US and was positive/suspicious in 2.9% (2/69) with normal ANC and 25.0% (14/56) with elevated ANC. MRI had 94.7% sensitivity and 100% specificity for acute appendicitis in patients with an Eq-US.

CONCLUSIONS

MRI has high sensitivity and specificity for diagnosing acute appendicitis in children. Patients with Eq-US plus a normal ANC have a very low likelihood of appendicitis and do not typically require further imaging. MRI may have utility for children with Eq-US and elevated ANC.

LEVEL OF EVIDENCE

Level III.

ACR Appropriateness Criteria® Right Lower Quadrant Pain-Suspected Appendicitis

Appendicitis remains the most common surgical pathology responsible for right lower quadrant (RLQ) abdominal pain presenting to emergency departments in the United States, where the incidence continues to increase. Appropriate imaging in the diagnosis of appendicitis has resulted in decreased negative appendectomy rate from as high as 25% to approximately 1% to 3%. Contrast-enhanced CT remains the primary and most appropriate imaging modality to evaluate this patient population. MRI is approaching CT in sensitivity and specificity as this technology becomes more widely available and utilization increases. Unenhanced MRI and ultrasound remain the diagnostic procedures of choice in the pregnant patient. MRI and ultrasound continue to perform best in the hands of experts. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Prospective evaluation of MRI compared with CT for the etiology of abdominal pain in emergency department patients with concern for appendicitis

BACKGROUND

Computed tomography (CT) is commonly used in the Emergency Department (ED) to evaluate patients with abdominal pain, but exposes them to ionizing radiation, a possible carcinogen. MRI does not utilize ionizing radiation and may be an alternative.

PURPOSE

To compare the sensitivity of MRI and CT for acute abdominopelvic ED diagnoses.

STUDY TYPE

Prospective, observational cohort.

POPULATION

ED patients ≥12 years old and undergoing CT for possible appendicitis.

FIELD STRENGTH/SEQUENCE

1.5 T MRI, including T₁ -weighted, T₂ -weighted, and diffusion-weighted imaging sequences.

ASSESSMENT

Three radiologists independently interpreted each MRI and CT image set separately and blindly, using a standard case report form. Assessments included likelihood of appendicitis, presence of an alternative diagnosis, and likelihood that the alternative diagnosis was causing the patient's symptoms. An expert panel utilized chart review and follow-up phone interviews to determine all final diagnoses. Times to complete image acquisition and image interpretation were also calculated.

STATISTICAL TESTS

Sensitivity was calculated for each radiologist and by consensus (≥2 radiologists in agreement) and are reported as point estimates with 95% confidence intervals. Two-sided hypothesis tests comparing the sensitivities of the three image types were conducted using Pearson's chi-squared test with the traditional significance level of P = 0.05.

RESULTS

There were 15 different acute diagnoses identified on the CT/MR images of 113 patients. Using individual radiologist interpretations, the sensitivities of noncontrast-enhanced MRI (NCE-MR), contrast-enhanced MR (CE-MR), and CT for any acute diagnosis were 77.0% (72.6-81.4%), 84.2% (80.4-88.0%), and 88.7% (85.5-92.1%). Sensitivity of consensus reads was 82.0% (74.9-88.9%), 87.1% (81.0-93.2%), 92.2% (87.3-97.1%), respectively. There was no difference in sensitivities between CE-MR and CT by individual (P = 0.096) or consensus interpretations (P = 0.281), although NCE-MR was inferior to CT in both modes of analysis (P < 0.001, P = 0.031, respectively).

DATA CONCLUSION

The sensitivity of CE-MR was similar to CT when diagnosing acute, nontraumatic abdominopelvic pathology in our cohort.

LEVEL OF EVIDENCE

2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:1651-1658.