The influence of body mass index on the accuracy of ultrasound and computed tomography in diagnosing appendicitis in children

Diagnostic Ultrasound for Acute Appendicitis: The Gold Standard

BACKGROUND

Acute appendicitis may present a diagnostic dilemma. The aim of this study was to review the accuracy of ultrasound in the diagnosis of paediatric acute appendicitis.

METHOD

Ultrasound studies performed for investigation of appendicitis during 2015-2021 were retrieved from a tertiary paediatric hospital database and reviewed. Medical records were reviewed to determine operative intervention, further imaging, and final diagnosis. Diagnostic accuracy was assessed by sensitivity, specificity, predictivity, and overall accuracy. All appendicectomy specimens underwent histopathological confirmation. This study was approved by the local Human Research Ethics Committee.

RESULTS

A total of 8555 consecutive ultrasound examinations were performed during the study period. Mean patient age was 10.8 years ( ± 3.7). Overall diagnostic accuracy was 96.1% (8221/8555) with a visualisation rate of 91.0%. Sensitivity and specificity were 96.2% (CI 95.3-97.0%) and 96.1% (CI 95.6-96.5%), respectively. When limited to positive/negative scans, sensitivity was 99.6% (CI 99.2-99.8%) and specificity 99.0% (CI 98.7-99.3%). Positive and negative predictive values were 96.9% and 99.9%, respectively. Repeat ultrasound following a non-diagnostic scan led to a definitive diagnosis in 76.1%. Negative appendicectomy rate was 5.5% overall in children who had undergone pre-operative ultrasound (107/1938), and 4.4% when other surgical pathologies were excluded.

CONCLUSION

Ultrasound examination provides gold-standard accuracy in the diagnosis of paediatric appendicitis and reduces rates of negative appendicectomy. Given the disadvantages of computed tomography and magnetic resonance imaging, ultrasound should be considered the first-line investigation of choice in the diagnosis of acute appendicitis in children.

LEVEL OF EVIDENCE

III.

Disparities in Ultrasound Use for Diagnosing Pediatric Appendicitis Across United States Emergency Departments

INTRODUCTION

An ultrasound (US)-first approach for evaluating appendicitis is recommended by the American College of Radiology. We sought to assess the access to and utilization of an US-first approach for children with acute appendicitis in United States Emergency Departments.

METHODS

Utilizing the 2019 Nationwide Emergency Department Sample, we performed a retrospective cohort study of patients <18 y with a primary diagnosis of acute appendicitis based on International Classification of Disease 10th Edition Diagnosis codes. Our primary outcome was the presentation to a hospital that does not perform US for children with acute appendicitis. Our secondary outcome was the receipt of a US at US-capable hospital. We developed generalized linear models with inverse-probability weighting to determine the association between patient characteristics and outcomes.

RESULTS

Of 49,703 total children, 24,102 (48%) received a US evaluation. The odds of presenting at a hospital with no US use were significantly higher for patients aged 11-17 compared to patients <6 y (adjusted odds ratio [aOR] [95% confidence interval (CI)]: 1.59, [1.19- 2.13], P = 0.002); lowest median household income quartile compared to highest (aOR [95% CI]: 2.50, [1.52-4.10], P < 0.001); rural locations compared to metropolitan (aOR [95% CI]: 8.36 [5.54-12.6], P < 0.001), and Hispanic compared to non-Hispanic White (aOR [95% CI]: 0.63 [0.45-0.90], P = 0.01). The odds of receiving a US at US-capable hospitals were significantly lower for patients >6 y, lowest median household income quartiles, and rural locations (P < 0.05).

CONCLUSIONS

Rural, older, and poorer children are more likely to present to hospitals that do not utilize US in the diagnosis of acute appendicitis and are less likely to undergo US at US-capable hospitals.

Diagnosis and treatment of appendicitis: systematic review and meta-analysis

BACKGROUND

The optimal diagnosis and treatment of appendicitis remains controversial. This systematic review details the evidence and current best practices for the evaluation and management of uncomplicated and complicated appendicitis in adults and children.

METHODS

Eight questions regarding the diagnosis and management of appendicitis were formulated. PubMed, Embase, CINAHL, Cochrane and clinicaltrials.gov/NLM were queried for articles published from 2010 to 2022 with key words related to at least one question. Randomized and non-randomized studies were included. Two reviewers screened each publication for eligibility and then extracted data from eligible studies. Random effects meta-analyses were performed on all quantitative data. The quality of randomized and non-randomized studies was assessed using the Cochrane Risk of Bias 2.0 or Newcastle Ottawa Scale, respectively.

RESULTS

2792 studies were screened and 261 were included. Most had a high risk of bias. Computerized tomography scan yielded the highest sensitivity (> 80%) and specificity (> 93%) in the adult population, although high variability existed. In adults with uncomplicated appendicitis, non-operative management resulted in higher odds of readmission (OR 6.10) and need for operation (OR 20.09), but less time to return to work/school (SMD - 1.78). In pediatric patients with uncomplicated appendicitis, non-operative management also resulted in higher odds of need for operation (OR 38.31). In adult patients with complicated appendicitis, there were higher odds of need for operation following antibiotic treatment only (OR 29.00), while pediatric patients had higher odds of abscess formation (OR 2.23). In pediatric patients undergoing appendectomy for complicated appendicitis, higher risk of reoperation at any time point was observed in patients who had drains placed at the time of operation (RR 2.04).

CONCLUSIONS

This review demonstrates the diagnosis and treatment of appendicitis remains nuanced. A personalized approach and appropriate patient selection remain key to treatment success. Further research on controversies in treatment would be useful for optimal management.

Factors contributing to uncertainty in paediatric abdominal ultrasound reports in the paediatric emergency department

BACKGROUND

Abdominal pain, which is a common cause of children presenting to the paediatric emergency department (PED), is often evaluated by ultrasonography (US). However, uncertainty in US reports may necessitate additional imaging.

OBJECTIVE

In this study, we evaluated factors contributing to uncertainty in paediatric abdominal US reports in the PED.

MATERIALS AND METHODS

This retrospective cohort study included children younger than 18 years of age who underwent abdominal US in the PED of the study hospital between January 2017 and December 2019. After exclusion, the researchers manually reviewed and classified all US reports as 'certain' or 'uncertain'. Univariate and multivariate logistic regression analyses were performed to identify the factors contributing to uncertain reports.

RESULTS

In total, 1006 patients were included in the final analysis., 796 patients were tagged as having certain reports, and 210 as having uncertain reports. Children with uncertain reports had a significantly higher rate of undergoing an additional computed tomography (CT) scan (31.0% vs. 2.5%, p < 0.001) and a longer PED median length of stay (321.0 (Interquartile range (IQR); 211.3-441.5) minutes vs. 284.5 (IQR; 191.8-439.5) minutes, p = 0.042). After logistic regression, US performed by a radiology resident (odds ratio, 5.01; 95% confidence interval, 3.63-7.15) was the most significant factor contributing to uncertainty in paediatric abdominal US reports followed by obesity and age.

CONCLUSION

Several factors contribute to uncertainty in paediatric abdominal US reports. Uncertain radiological reports increase the likelihood of additional CT scans. Measures to improve the clarity of radiological reports must be considered to improve the quality of care for children visiting the PED.

Recent Trend of Using Computed Tomography to Diagnose Pediatric Appendicitis at the First Hospital Visit: A Descriptive Study Using a Medical Claims Database

OBJECTIVE

We recognize that computed tomography (CT) should not be used to diagnosis pediatric appendicitis due to radiation exposure. However, few studies have recently shown a trend in its use. This study aimed to investigate the annual use of CT for the diagnosis of pediatric appendicitis at the first hospital visit.

METHODS

This was a descriptive study using nationwide claims data. We extracted the data of children younger than 15 years who underwent imaging tests to diagnose acute and suspected appendicitis at the first visit between January 2008 and September 2018. We summarized the patient characteristics and the percentage of CT, ultrasonography (US), or CT/US utilization by year, age, and department.

RESULTS

We identified 6658 children who underwent CT (2349 [35.8%]), US (53,57 [54.5%]), and CT/US (634 [9.7%]). The annual CT use dropped from 43.1% in 2012 to 29.4% in 2018. According to age group, the highest percentage of CT use in 2018 was 84.6% in preschool children, followed by adolescents (40.3%), upper-grade (26.0%), and lower-grade (15.0%) children. Data of annual CT use by department revealed that CT usage was much higher in internal and emergency medicine than in pediatrics. Furthermore, adolescents accounted for approximately 50% of CT use in internal medicine.

CONCLUSIONS

The percentage of CT use for pediatric appendicitis at the first visit declined annually. However, CT use still tended to be higher in preschool- and adolescent-aged children, or in departments other than pediatrics. Further studies are required to clarify the clinical benefits of CT use to diagnose pediatric appendicitis.

Structured coaching as a means to improve sonographic visualization of the appendix: a quality improvement initiative

PURPOSE

Ultrasound of the right lower quadrant for appendicitis requires specific training and practice. Improved visualization of the appendix can result in decreased utilization of computed tomography. Increasing the sensitivity of ultrasound for appendicitis thus decreases radiation exposure, reduces cost, and improves the patient healthcare experience in accordance with the three principles of the triple aim designated by the Institute for Healthcare Improvement. The purpose of this study was to examine the effect of a structured training program supplemented by technologist feedback on sonographic visualization of the appendix in a large pediatric health system.

METHODS

The baseline ultrasound visualization frequency was computed for 20 ultrasound technologists in a large pediatric health system. Following this, technologists were informed of their individual and relative performance. Those with visualization frequencies less than 75% were provided structured training by a designated sonographer with an appendix visualization frequency above 75% while those with greater than 75% visualization continued to be monitored and informed of their monthly frequency. Following this structured training, appendix visualization frequencies were monitored over the next 5 months.

RESULTS

There was no significant effect of sonographer career experience on the baseline appendix visualization frequency. Fourteen of 20 technologists demonstrated improved visualization frequencies post-intervention. The composite visualization frequency among these 20 technologists improved from 66.55 to 69.14%. This resulted in a potential savings of 38 CT scans during the post-intervention period.

CONCLUSION

An appendix visualization rate monitoring program coupled with structured training was successful in improving the appendix visualization rate throughout a large pediatric health system. This program demonstrates the positive effect that monitoring and targeted intervention can have on a quality improvement program. The program continues to be carried out as part of a plan-study-do-act cycle.

A Standardized Diagnostic Pathway for Suspected Appendicitis in Children Reduces Unnecessary Imaging

Ultrasound (US) for the diagnosis of acute appendicitis is often nondiagnostic, and additional imaging is required. A standardized approach may reduce unnecessary imaging.

Body mass index as a predictor of sonographic visualization of the pediatric appendix

BACKGROUND

Appendicitis is a common condition that is often confirmed with imaging. Ultrasound (US) is recommended as the first radiologic test in the work-up of appendicitis in children. Increased body mass index (BMI) has been implicated as a limiting factor to the sensitivity of US. This has drastic public health ramifications, as pediatric obesity has been increasing at alarming rates.

OBJECTIVE

The purpose of this study is to compare age-adjusted BMI z-scores to the frequency of sonographic visualization of the appendix.

MATERIALS AND METHODS

A retrospective review of 500 consecutive reports of US exams ordered for appendicitis in patients with a documented BMI was performed. Patients were stratified by BMI z-score based on, and the visualization frequency of the appendix was compared to the BMI z-score group. A logistic regression analysis generated the odds of visualization of the appendix by BMI z-score group. Primary home language, ethnicity, sex and insurance status were included in the logistic regression model to assess these characteristics as potential effect modifiers.

RESULTS

Of the 500 patients, 52.4% were male, 56.4% were Hispanic and 62.0% had government insurance. BMI z-score distribution groups were as follows: 4.2% were <-2, 8.0% were -2 to -1, 49.8% were -1 to 1, 26.4% were 1 to 2 and 11.6% were >2. The visualization frequency was 61.1% for boys and 46.2% for girls (P<0.05). Visualization frequency by BMI z-score group was as follows: 85.7% for <2, 72.5% for -2 to -1, 57.4% for -1 to 1, 47.7% for 1 to 2 and 29.3% for >2. Children with a BMI z-score greater than 2 were less likely to have a US with visualization of the appendix compared to children with a BMI z-score between -1 and 1 (adjusted odds ratio [aOR]: 0.21, 95% CI: 0.11-0.40, P<0.0001). Boys were more likely than girls to have a US with visualization of the appendix (aOR: 1.90, 95% CI: 1.29-2.80, P=0.001). There was no effect from insurance status, ethnicity or primary home language.

CONCLUSION

Findings show that as the BMI z-score increased, sonographic visualization of the appendix decreased even after adjusting for demographic differences. These findings have implications for pediatric radiology practice in light of the worsening obesity epidemic.

Pre-Coronavirus Disease 2019 Pediatric Acute Appendicitis: Risk Factors Model and Diagnosis Modality in a Developing Low-Income Country

PURPOSE

Pediatric acute appendicitis has a stable incidence rate in Western countries with an annual change of -0.36%. However, a sharp increase was observed in the Asian region. The Indonesian Health Department reveals appendicitis as the fourth most infectious disease, with more than 64,000 patients annually. Hence, there is an urgent need to identify and evaluate the risk factors and diagnostic modalities for accurate diagnosis and early treatment. This study also clarifies the usage of pediatric appendicitis score (PAS) for children <5 years of age.

METHODS

The current study employed a cross-sectional design with purposive sampling through demographic and PAS questionnaires with ultrasound sonography (USG) results. The analysis was performed using the chi-square and Mann-Whitney tests and logistic regression.

RESULTS

This study included 21 qualified patients with an average age of 6.76±4.679 years, weighing 21.72±10.437 kg, and who had been hospitalized for 4.24±1.513 days in Siloam Teaching Hospital. Compared to the surgical gold standard, PAS and USG have moderate sensitivity and specificity. Bodyweight and stay duration were significant for appendicitis (p<0.05); however, all were confounders in the multivariate regression analysis. Incidentally, a risk prediction model was generated with an area under the curve of 72.73%, sensitivity of 100.0%, specificity of 54.5%, and a cut-off value of 151.

CONCLUSION

PAS outperforms USG in the sensitivity of diagnosing appendicitis, whereas USG outperforms PAS in terms of specificity. This study demonstrates the use of PAS in children under 5 years old. Meanwhile, no risk factors were significant in multivariate pediatric acute appendicitis risk factors.

Applying the Pediatric Appendicitis Score to predict complicated appendicitis in children

BACKGROUND

This study aimed to investigate the efficacy of the Pediatric Appendicitis Score (PAS) and other indicators to enable the prediction of complicated appendicitis (CA) in children.

METHODS

This retrospective cohort study evaluated children (n = 161) aged ≤16 years with acute appendicitis between 2008 and 2020. Demographic data, symptoms, physical findings, laboratory data, and PASs were collected. Multivariate analysis was performed to identify predictors for CA. Receiver operating characteristic (ROC) curves were constructed. The diagnostic performance of each predictor was evaluated.

RESULTS

Multivariate analysis identified three predictors for CA: duration of symptoms >1 day, C-reactive protein (CRP) level > 4 mg/dL, and PAS ≥ 8. The ROC curve of the combined three predictors showed an area under the curve of 0.91. The multivariate ROC curve revealed that the presence of a PAS contributed to a significant improvement in the diagnosis of CA compared to the absence of PAS. When combined, the three predictors had a high specificity of 99% and positive predictive value of 98%.

CONCLUSIONS

A symptom duration >1 day, CRP > 4 mg/dL, and PAS ≥ 8 were predictors for CA. The PAS can be useful for prediction of CA when combined with the duration of symptoms, CRP, or both.

Diagnostic Applications of Point-of-Care Ultrasound in Pediatric Emergency Medicine

Point-of-care ultrasound has become an essential part of pediatric emergency medicine training and practice. It can have significant clinical benefits, including improving diagnostic accuracy and decreasing length of stay, and does not require radiation exposure for patients. In this review, we summarize the current diagnostic point-of-care ultrasound applications in pediatric emergency medicine, their evidence, and techniques.

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.

Evaluating Changes in Diagnostic Accuracy of Ultrasound for Appendicitis: Does Practice Make Perfect?

BACKGROUND

Ultrasound (US) is the preferred method of initial evaluation for appendicitis in pediatrics. However, limited accuracy of US for appendicitis is an obstacle to implementation of US-first protocols at facilities less experienced with US.

OBJECTIVES

The primary objective was to demonstrate changes in diagnostic accuracy of US for appendicitis over time, after implementation of an US-first protocol. Secondary objectives included evaluating trends in utilization and factors associated with accuracy of US.

METHODS

We reviewed 5 years of pediatric emergency department encounters that included US evaluations for appendicitis. The primary outcome was conclusive US (fully visualized normal appendix or unequivocal appendicitis) vs. equivocal US (partially visualized or nonvisualized appendix). We also analyzed rates of conclusive US over time; accuracy, sensitivity, and specificity of US for appendicitis; and associations of US accuracy with patient gender, body mass index, and ultrasonographer's experience.

RESULTS

A conclusive US report was found in 267 of 1058 encounters (25.2%); overall accuracy rate was 24.5%. Over 5 years, the diagnostic accuracy of US for appendicitis improved significantly from 13.9% to 31.5% (p = 0.001). Overall sensitivity was 80.7% and specificity was 77.6%. Male gender and dedicated US of the appendix were significantly associated with conclusive US (ps < 0.001). Higher body mass index was significantly associated with equivocal US (p < 0.001). Ultrasonographer experience was not significantly associated with conclusive US (p = 0.22).

CONCLUSIONS

An US-first imaging protocol for appendicitis in children shows chronologic improvement in diagnostic accuracy. This may provide encouragement to facilities using computed tomography-based diagnostic protocols to implement US-first protocols to reduce childhood radiation exposure.

Decreasing Accuracy of the eFAST Examination—Another Challenge Due to Morbid Obesity

The extended focused assessment with sonography for trauma (eFAST) ultrasound examination is an essential step in the initial assessment of trauma patients. Its accuracy depends on the ability to acquire high-quality ultrasound images, and we hypothesized that increasing BMI was associated with increased odds for incorrect eFAST. All adult blunt trauma activations at a high-volume urban trauma center in 2016 that underwent eFAST and CT chest, abdomen, and pelvis were included (n = 446). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the eFAST were calculated with CT results as reference. The association of BMI and eFAST accuracy was determined using univariate analyses. Sensitivity and specificity of the eFASTexamination were 27.1 per cent and 91.7 per cent, respectively, with an overall 76.2 per cent accuracy. At BMI 36 kg/m2, the odds of having incorrect eFAST results increased to odds ratio (OR) = 1.85 (95% confidence interval, 1.03–3.32; P = 0.05). For those with BMI > 40 kg/m2, the OR increased to OR = 3.12 (95% confidence interval, 1.45–6.69; P = 0.01). One-third of patients in this study were obese or morbidly obese. The latter was associated with increased odds for incorrect eFAST results, particularly the abdominal examination component.

Correlating Abdominal Wall Thickness and Body Mass Index to Predict Usefulness of Right Lower Quadrant Ultrasound for Evaluation of Pediatric Appendicitis

OBJECTIVES

To inform selective and efficient use of appendix ultrasound (US) beyond adult parameters of body mass index (BMI) of less than 25 kg/m, we correlate abdominal wall thickness (AWT) with age and BMI to generate parameters for male and female children. Information presented in chart format can aid in the decision to utilize US for the evaluation of appendicitis.

METHODS

In this observational study, 1600 pediatric computed tomography scans of the abdomen and pelvis were analyzed to obtain measurements of AWT in the right lower quadrant. Measurements were correlated by patient age, BMI, and sex. Results and consensus-based recommendations were presented in chart format with color-coded groupings to allow for convenient referencing in the clinical setting.

RESULTS

One thousand four hundred eighty-eight computed tomography scans and AWT measurements were included. All age groups with BMI of less than 25 kg/m and all male and female groups younger than 6 years regardless of BMI had median AWT of less than 4 cm resulting in strong recommendation for US. Males older than 6 years and all female age groups with BMI of greater than 30 kg/m and female older than 15 years and BMI of greater than 25 kg/m had AWT of more than 5 cm resulting in low recommendation for US.

CONCLUSIONS

While the BMI cutoff standard of less than 25 kg/m for usefulness of appendix US holds in the adult population, our data expand the acceptable range in children younger than 9 years regardless of BMI and male children with BMI up to 30 kg/m. Female children younger than 15 years with a BMI up to 30 kg/m may also be amenable to right lower quadrant US based on AWT. These parameters inform selective and efficient use of US for appendix evaluation.

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.

Falling through the worm hole: an exploration of the imaging workup of the vermiform appendix in the pediatric population

Despite the thousands of articles discussing appendicitis in the literature, the dilemma of how to best diagnosis and manage pediatric appendicitis remains unsettled. Over the past decade, evidence has been mounting about the use of antibiotics as the sole therapy in uncomplicated appendicitis in the adult population. This debate has even recently bled over into the lay press. While this change in practice pattern is still in its infancy for the pediatric population, radiologists should be aware of this change in therapy and how it can impact the imaging work-up and relevant findings. This article concisely summarizes the imaging findings and various imaging pathways to arrive at the diagnose of appendicitis with an emphasis of how to best be of use to our surgical colleagues in this evolving paradigm. It also highlights venues for further research, namely increasing accuracy of differentiating complicated from uncomplicated appendicitis.

Suspected appendicitis pathway continues to lower CT rates in children two years after implementation

BACKGROUND

We implemented a protocol to evaluate pediatric patients with suspected appendicitis using ultrasound as the initial imaging modality. CT utilization rates and diagnostic accuracy were evaluated two years after pathway implementation.

METHODS

This was a retrospective observational study of patients <18 years evaluated for suspected appendicitis. CT rates were compared before and after implementation of the protocol, and monthly CT rates were calculated to assess trends in CT utilization.

RESULTS

CT use decreased significantly following pathway implementation from 94.2% (130/138) to 27.5% (78/284; p < 0.001). Linear regression of monthly CT utilization demonstrated that CT rates continued to trend down two years after pathway implementation. Adherence to the pathway was 89.8% (255/284). Negative appendectomy rate was 2.4% (2/85) in the post-pathway period.

CONCLUSIONS

Adherence to a pathway designed to evaluate pediatric patients with suspected appendicitis using ultrasound as the primary imaging modality has led to a sustained decrease in CT use without compromising diagnostic accuracy.

National Trends in Diagnostic Imaging for Appendicitis: A Cross-Sectional Analysis Using NSQIP

Prior studies elucidate a high predictive value of imaging to diagnose appendicitis in small, regional cohorts. This cross-sectional study uniquely analyzes diagnostic imaging in a national appendectomy population. Using the 2016 ACS NSQIP database, positive predictive values (PPVs) for CT, ultrasound (US), and MRI were evaluated using chi-squared tests. Univariate and multivariate analyses considered patient-specific factors. Imaging was performed in 94.63 per cent of 11,841 appendectomy cases; most frequently via CT (78.69%), then combination CT and US (7.52%), US (7.15%), and MRI (0.30%). CT PPV was higher in overweight (98.70%) versus underweight patients (94.85%) ( P = 0.01). Gender and age did not impact CT PPV. Imaging from a referral site did not change CTor US PPV. Our study describes imaging frequencies and confirms high PPV. We found imaging equally predictive in women of childbearing age and elderly individuals compared with the general population. Furthermore, repeat scanning is unnecessary with prior positive imaging at outside sites.

Accuracy of Right Upper Quadrant Ultrasound in Estimating Gallbladder Wall Thickness

OBJECTIVE

Ultrasound (US) evaluation of biliary pathology can be influenced by a variety of factors. This study examines the effect of patient specific factors on the accuracy of sonographic evaluation of gallbladder wall thickness (GBW).

METHODS

We performed a retrospective review of all patients who underwent cholecystectomy at a single institution from November 2012 to October 2015. GBW measured on US was compared with pathology results. Results were analyzed in relation to patient specific factors to include BMI, age, presence of diabetes, sex, and urgent versus elective cases.

RESULTS

In total 601 patients underwent cholecystectomy, 484 of which had paired preoperative US GBW measurement and postoperative pathologic specimen measurement. No significant difference in accuracy or precision of US measurement of the GBW based on BMI was found. Accuracy was not related to age, sex, urgency, or diabetes. Precision decreased with pathologic thickening, age, male sex, and urgent case performance.

CONCLUSIONS

US is accurate in measuring GB wall thickness regardless of patient specific factors. A nonsignificant trend exists with decreased precision with pathologic thickening, age, male sex, and urgently performed cases.

Diagnostic accuracy of surgeon performed ultrasound (SPU) for appendicitis in children

AIM

Compare the diagnostic accuracy of surgeon performed ultrasound to radiology performed ultrasound in children presenting with suspected appendicitis to a tertiary care pediatric hospital in Australia.

METHODS

Children under 16 presenting to the emergency department of The Children's Hospital at Westmead were considered for the study. Patients with obvious signs of appendicitis not requiring ultrasound and those with established ultrasound diagnosis of appendicitis were excluded. Ultrasound was performed by a Pediatric Surgeon (SPU) after obtaining consent. The treating team was blinded to the results. Patient underwent formal ultrasound in radiology (RPU) and treatment was based on the formal report. SPU result was reviewed by a radiologist blinded to results of RPU. The results were compared.

RESULTS

65 children underwent ultrasound. 35 were male. Median age was 10 (range3-15). Median weight was 36 kg (range 12.6-76.2 kg), z-score median 0.21 (-1.83 to 2.74). Symptom duration ranged from few hours to 2 weeks but majority (45) had symptoms for less than 48 h. Prevalence of appendicitis was 45%. Thirty two underwent surgery. Negative appendicectomy rate was 9.4%. Thirty three did not have surgery. 8 represented but only one proceeded to appendicectomy. SPU was done earlier than RPU (median 12 h vs 14.15 h) p = 0.088. Diagnostic accuracy using ROC did not reveal significant difference.

CONCLUSION

SPU can be performed earlier than RPU with reliable accuracy. Training surgical trainees will enable early diagnosis and management of appendicitis.

Practical Imaging Strategies for Acute Appendicitis in Children

OBJECTIVE

Diagnosing pediatric appendicitis is difficult because clinical findings are nonspecific. Improved accuracy can be obtained with ultrasound (US), CT, or MRI, despite considerable variation in their use at different institutions. This article reviews the evidence for best practices in imaging pediatric appendicitis.

CONCLUSION

When each modality is optimally used, a stepwise imaging approach that begins with graded compression US and proceeds to CT or MRI in select cases is currently best practice.

Diagnostic performance of emergency physician-performed point-of-care ultrasonography for acute appendicitis: A meta-analysis

OBJECTIVE

To assess the sensitivity and specificity of emergency physician-performed point-of-care ultrasonography (EP-POCUS) for diagnosing acute appendicitis (AA).

MATERIAL AND METHODS

The PubMed and EMBASE databases were searched, and the diagnostic performance of EP-POCUS was evaluated using bivariate modeling and hierarchical summary receiver operating characteristic curves. Subgroup analysis was performed for pediatric patients to compare EP-POCUS and radiologist-performed ultrasonography (RADUS). Meta-regression analyses were performed according to patient and study characteristics.

RESULTS

In 17 studies (2385 patients), EP-POCUS for diagnosing AA exhibited a pooled sensitivity of 84% (95% confidence interval [CI]: 72%-92%) and a pooled specificity of 91% (95% CI: 85%-95%), with even better diagnostic performance for pediatric AA (sensitivity: 95%, 95% CI: 75%-99%; specificity: 95%, 95% CI: 85%-98%). A direct comparison revealed no significant differences (p = 0.18-0.85) between the diagnostic performances of EP-POCUS (sensitivity: 81%, 95% CI: 61%-90%; specificity: 89%, 95% CI: 77%-95%) and RADUS (sensitivity: 74%, 95% CI: 65%-81%; specificity: 97%, 95% CI: 93%-98%). The meta-regression analyses revealed that study location, AA proportion, and mean age were sources of heterogeneity. Higher sensitivity and specificity tended to be associated with an appendix diameter cut-off value of 7 mm and the EP as the initial operator.

CONCLUSION

The diagnostic performances of EP-POCUS and RADUS were excellent for AA, with EP-POCUS having even better performance for pediatric AA. Accurate diagnoses may be achieved when the attending EP is the initial POCUS operator and uses a 7-mm cut-off value.

Diagnostic performance of CT for pediatric patients with suspected appendicitis in various clinical settings: a systematic review and meta-analysis

OBJECTIVE

To assess the diagnostic performance of CT for pediatric patients with suspected appendicitis in various clinical settings and the proportion of acute appendicitis on final diagnosis among equivocal CT findings.

METHODS

MEDLINE and EMBASE databases were searched until October 21, 2017, for studies investigating diagnostic performance of CT for acute appendicitis in pediatric patients confirmed by histopathologic findings and/or clinical follow-up. Pooled estimates of sensitivity and specificity were calculated using a hierarchical logistic regression modeling. The proportion of true appendicitis among patients with inconclusive CT results was obtained using fixed and random effects meta-analyses.

RESULTS

Twenty-two articles with 3396 patients were included. The pooled sensitivity and specificity were 95% (95% CI, 93-97%) and 94% (95% CI, 90-96%), respectively, and the area under the hierarchical summary receiver operating characteristic (HSROC) curve was 0.98 (95% CI, 0.96-0.99). Subgroup analyses revealed a comparable diagnostic performance in the low-dose CT group (sensitivity, 97%; specificity, 96%) and the unenhanced group (sensitivity, 95%; specificity, 95%). Other subgroups (publication year, study design, enrolled population, true appendicitis proportion, CT channel number, and slice thickness) also showed good diagnostic performance. Six studies reporting the true appendicitis proportion among patients with equivocal CT findings had pooled proportion of 17% (95% CI, 9-29%).

CONCLUSIONS

CT showed good performance for suspected appendicitis in pediatric patients under various clinical settings, including in cases with dose reduction or absence of IV contrast. The prevalence of true appendicitis among patients with equivocal appendicitis results on CTs was not low; therefore, clinical attention should not be disregarded in this population.

Point-of-Care Ultrasound Integrated Into a Staged Diagnostic Algorithm for Pediatric Appendicitis

OBJECTIVES

We hypothesized that point-of-care ultrasound (POCUS) is as accurate as radiology-performed ultrasound in evaluating children with clinical concern for appendicitis. As part of a staged approach, we further hypothesized that POCUS could ultimately decrease computed tomography (CT) utilization.

METHODS

This was a prospective, convenience sampling of patients aged 2 to 18 years presenting with abdominal pain to a pediatric emergency department. Those patients with prior abdominal imaging, pregnant, or unable to tolerate the examination were excluded. An algorithm was followed: POCUS was first performed, followed by a radiology-performed ultrasound, and then a CT as necessary. The main outcome measure was the accuracy of the POCUS in diagnosing of appendicitis. This was compared with radiology-performed ultrasound. We also examined whether certain patient or clinical characteristics influenced the performance of POCUS. Lastly, we determined the amount by which CT scans were decreased through this staged algorithm.

RESULTS

Forty patients were enrolled and underwent a POCUS examination. A total of 16 (40%) had pathology-confirmed appendicitis. Point-of-care ultrasound had a sensitivity of 93.8% (95% confidence interval [CI], 69.7%-98.9%) and specificity of 87.5% (95% CI, 67.6%-97.2%). Radiology-performed ultrasound had a sensitivity of 81.25% (95% CI, 54.3%-95.7%) and specificity of 100% (95% CI, 85.6%-100%). The radiology-performed and POCUS examinations had very good agreement (κ = 0.83, P < 0.0005). Patient characteristics including body mass index did not have an affect on the POCUS. However, POCUS identified all patients with an Alvarado score higher than 6. Overall, the reduction in CT examinations was 55%.

CONCLUSIONS

In pediatric patients presenting with clinical concern for acute appendicitis, a staged algorithm that incorporates POCUS is accurate and has the potential to decrease CT scan utilization.

Differentiating perforated from non-perforated appendicitis on contrast-enhanced magnetic resonance imaging

BACKGROUND

The role of magnetic resonance imaging (MRI) in pediatric appendicitis is increasing; MRI findings predictive of appendiceal perforation have not been specifically evaluated.

OBJECTIVE

To assess the performance of MRI in differentiating perforated from non-perforated appendicitis.

MATERIALS AND METHODS

A retrospective review of pediatric patients undergoing contrast-enhanced MRI and subsequent appendectomy was performed, with surgicopathological confirmation of perforation. Appendiceal diameter and the following 10 MRI findings were assessed: appendiceal restricted diffusion, wall defect, appendicolith, periappendiceal free fluid, remote free fluid, restricted diffusion within free fluid, abscess, peritoneal enhancement, ileocecal wall thickening and ileus. Two-sample t-test and chi-square tests were used to analyze continuous and discrete data, respectively. Sensitivity and specificity for individual MRI findings were calculated and optimal thresholds for measures of accuracy were selected.

RESULTS

Seventy-seven patients (mean age: 12.2 years) with appendicitis were included, of whom 22 had perforation. The perforated group had a larger mean appendiceal diameter and mean number of MRI findings than the non-perforated group (12.3 mm vs. 8.6 mm; 5.0 vs. 2.0, respectively). Abscess, wall defect and restricted diffusion within free fluid had the greatest specificity for perforation (1.00, 1.00 and 0.96, respectively) but low sensitivity (0.36, 0.25 and 0.32, respectively). The receiver operator characteristic curve for total number of MRI findings had an area under the curve of 0.92, with an optimal threshold of 3.5. A threshold of any 4 findings had the best ability to accurately discriminate between perforated and non-perforated cases, with a sensitivity of 82% and specificity of 85%.

CONCLUSION

Contrast-enhanced MRI can differentiate perforated from non-perforated appendicitis. The presence of multiple findings increases diagnostic accuracy, with a threshold of any four findings optimally discriminating between perforated and non-perforated cases. These results may help guide management decisions as MRI assumes a greater role in the work-up of pediatric appendicitis.

Evaluating the risk of appendiceal perforation when using ultrasound as the initial diagnostic imaging modality in children with suspected appendicitis

BACKGROUND

Ultrasound scan has gained attention for diagnosing appendicitis due to its avoidance of ionizing radiation. However, studies show that ultrasound scan carries inferior sensitivity to computed tomography scan. A non-diagnostic ultrasound scan could increase the time to diagnosis and appendicectomy, particularly if follow-up computed tomography scan is needed. Some studies suggest that delaying appendicectomy increases the risk of perforation.

OBJECTIVE

To investigate the risk of appendiceal perforation when using ultrasound scan as the initial diagnostic imaging modality in children with suspected appendicitis.

METHODS

We retrospectively reviewed 1411 charts of children ≤17 years old diagnosed with appendicitis at two urban academic medical centers. Patients who underwent ultrasound scan first were compared to those who underwent computed tomography scan first. In the sub-group analysis, patients who only received ultrasound scan were compared to those who received initial ultrasound scan followed by computed tomography scan. Main outcome measures were appendiceal perforation rate and time from triage to appendicectomy.

RESULTS

In 720 children eligible for analysis, there was no significant difference in perforation rate between those who had initial ultrasound scan and those who had initial computed tomography scan (7.3% vs. 8.9%, p = 0.44), nor in those who had ultrasound scan only and those who had initial ultrasound scan followed by computed tomography scan (8.0% vs. 5.6%, p = 0.42). Those patients who had ultrasound scan first had a shorter triage-to-incision time than those who had computed tomography scan first (9.2 (IQR: 5.9, 14.0) vs. 10.2 (IQR: 7.3, 14.3) hours, p = 0.03), whereas those who had ultrasound scan followed by computed tomography scan took longer than those who had ultrasound scan only (7.8 (IQR: 5.3, 11.6) vs. 15.1 (IQR: 10.6, 20.6), p < 0.001). Children < 12 years old receiving ultrasound scan first had lower perforation rate (p = 0.01) and shorter triage-to-incision time (p = 0.003).

CONCLUSION

Children with suspected appendicitis receiving ultrasound scan as the initial diagnostic imaging modality do not have increased risk of perforation compared to those receiving computed tomography scan first. We recommend that children <12 years of age receive ultrasound scan first.

Body Mass Index is a Poor Predictor of Bedside Appendix Ultrasound Success or Accuracy

Introduction

The objective of this study was to determine whether there is a relationship between body mass index (BMI) and success or accuracy rate of beside ultrasound (BUS) for the diagnosis of appendicitis.

Methods

Patients four years of age and older presenting to the emergency department with suspected appendicitis were eligible. Enrollment was by convenience sampling. After informed consent, BUS was performed by trained emergency physicians who had undergone a minimum of one-hour didactic training on the use of BUS to diagnose appendicitis. We ascertained subject outcomes by a combination of medical record review and telephone follow up. Calculated BMI for adults and children were divided into four categories (underweight, normal, overweight, obese) according to Centers for Disease Control and Prevention classifications.

Results

A total of 125 subjects consented for the study, and 116 of them had adequate image data for final analysis. Seventy (60%) of the subjects were children. Prevalence of appendicitis was 39%. Fifty-two (45%) of the BUS studies were diagnostic (successful). Overall accuracy rate was 75%. Analysis by chi-square test or Mann-Whitney U test did not find any significant correlation between BMI category and BUS success. Similarly, there was no significant correlation between BMI category and BUS accuracy. The same conclusion was reached when children and adults were analyzed separately, or when subjects were dichotomized into underweight/normal and overweight/obese categories.

Conclusion

BMI category alone is a poor predictor of appendix BUS success or accuracy.

Diagnostic imaging practices for children with suspected appendicitis evaluated at definitive care hospitals and their associated referral centers

PURPOSE

The purpose of this study was to compare rates of ultrasound (US) and computed tomography (CT) for suspected appendicitis at hospitals able to provide definitive surgical care with those from their associated referral hospitals.

METHODS

A retrospective cohort study of children undergoing appendectomy using the Pediatric NSQIP Appendectomy Pilot Database (1/1/2013-8/31/2014) was performed. Imaging rates at the initial hospital of presentation were compared between groups after adjusting for differences in demographic characteristics.

RESULTS

We identified 4859 patients from 28 definitive care hospitals, of which 35% underwent diagnostic imaging at a referral hospital prior to transfer (range: 20.3-70.4%). The overall odds of receiving a CT scan was 10.9-times greater (95% CI: 9.4-12.5) at referring hospitals compared to definitive care hospitals, and the odds were significantly higher for referral hospitals in 96% (27/28) of the geographic regions represented. The overall odds of an initial attempt at US prior to CT was 11.1 times greater (95% CI: 9.09-14.28), and the odds of receiving any ultrasound was 6.25-times greater (95% CI: 5.26-7.14) at definitive care hospitals compared to referral hospitals.

CONCLUSIONS

Children initially evaluated for suspected appendicitis at referring hospitals are much more likely to receive a diagnostic CT, and those imaged with CT are much less likely to receive an US as the initial diagnostic test.

Lower Abdominal Pain

Although most frequently presenting with lower abdominal pain, appendicitis, colitis, and diverticulitis can cause pain throughout the abdomen and can cause peritoneal and retroperitoneal symptoms. Evaluation and management of lower intestinal disease requires a nuanced approach by the emergency physician, sometimes requiring computed tomography, ultrasonography, MRI, layered imaging, shared decision making, serial examination, and/or close follow-up. Once a presumed or confirmed diagnosis is made, appropriate treatment is initiated, and may include surgery, antibiotics, and/or steroids. Appendicitis patients should be admitted. Diverticulitis and inflammatory bowel disease can frequently be managed on an outpatient basis, but may require admission and surgical consultation.

Revival of the use of ultrasound in screening for appendicitis in young adult men

PURPOSE

Our primary aim was to evaluate the use of ultrasound (US) as an initial screening test for diagnosing appendicitis in young adult men. Secondary exploratory analyses included the effects of using US for initial screening in these patients, compared with the use of CT, on radiation exposure, length of stay (LOS), and cost of imaging.

METHODS

We retrospectively gathered data from the records of male patients 18-39 years old who had been admitted with appendicitis between June 2006 and September 2011. We investigated the diagnostic tests performed, the patients' characteristics, and the pathologic testing findings and compared the results obtained on US with those obtained on CT.

RESULTS

Of 451 included patients, 86 had undergone US initially. Its sensitivity was only 57% (95% confidence interval, 46-67.6), but its positive predictive value was 98% (95% confidence interval, 93.8-100). The mean LOS was significantly shorter for patients who had undergone US only (214 minutes) than it was for those who had undergone CT only (276 minutes; p < 0.001). We estimated a 57% reduction in CT use and radiation exposure if US were to be performed initially; this would lead to a 45% decrease in imaging costs at our institution.

CONCLUSIONS

Screening US should be considered first for diagnosing appendicitis because of its high positive predictive value, but even if US results are negative for appendicitis, one should not exclude the possible existence of pathology because US has poor sensitivity in this situation. We speculate that the use of screening US can decrease radiation exposure, imaging costs, and LOS.

The influence of underweight and obesity on the diagnosis and treatment of appendicitis in children

PURPOSE

The impact of lower body mass index (BMI) on appendicitis has never been addressed. We investigated whether different BMIs affect the diagnosis and treatment of appendicitis in children.

METHODS

The correlation between BMI and diagnosis accuracy and treatment quality was evaluated by retrospective analysis of 457 children diagnosed with appendicitis. Based on BMI percentiles, patients were classified as either underweight (n = 36), normal weight (n = 346), overweight (n = 59), or obese (n = 16). Diagnosis accuracy was measured by negative appendectomy rate, perforation rate, and number of consultations. Treatment quality was measured by complication rate and length of hospital stay.

RESULTS

Underweight patients had the highest negative appendectomy (OR 3.00, P = 0.008) and complication (OR 2.75, P = 0.041) rate. BMI did not influence perforation rate or number of consultations. Both underweight and obese patients stayed in the hospital longer than normal weight patients (regression coefficient 2.34, P = 0.001, and regression coefficient 9.40, P < 0.001, respectively). Furthermore, in obese patients, the hospital stay after open appendectomy was prolonged compared to laparoscopic appendectomy (P < 0.001). No such differences were observed in patients with lower BMI.

CONCLUSIONS

Underweight children are misdiagnosed more often, stay in hospital longer, and experience more postoperative complications than children of normal weight. Obesity is associated with longer hospital stays. Laparoscopic appendectomy might shorten the length of hospital stays in these patients. We conclude that in addition to obesity, underweight should also be considered a risk factor for children with appendicitis.

Pediatric appendiceal ultrasound: accuracy, determinacy and clinical outcomes

BACKGROUND

Ultrasonography is considered the most appropriate initial imaging study in the evaluation of acute appendicitis in children but has recently come under criticism with reports of low specificity and high indeterminate study rates, particularly when used in obese patients and patients early in the course of their disease, or when performed by sonographers with limited experience.

OBJECTIVE

To (1) assess the impact of patient factors (gender, age, body mass index, and symptom duration) and system factors (call status or year of exam) on pediatric appendiceal US accuracy and indeterminate study rate, (2) assess the impact of indeterminate study results on follow-up CT and negative laparotomy rates and (3) present strategies to reduce the rate of indeterminate US studies and improve accuracy.

MATERIALS AND METHODS

We retrospectively reviewed all US reports performed for the assessment of acute appendicitis in children <18 years old at Mayo Clinic Rochester from January 2010 to June 2014.

RESULTS

A total of 790 US examinations were performed in 452 girls (57%) and 338 boys (43%). The prevalence of appendicitis was 18.5% (146/790). There were 109 true-positive, 440 true-negative, 17 false-positive, 6 false-negative, 218 equivocal and 41 technically inadequate US studies. A definitive interpretation was made in 72% of the studies, with an accuracy, sensitivity and specificity of 0.960, 0.948 and 0.963, respectively. No patient or system factors significantly affected US accuracy. Indeterminate studies (28%) had significantly higher CT utilization (46% vs. 11%) and normal appendectomy rates (6.9% vs. 3.5%).

CONCLUSION

US should be the initial imaging study of choice for pediatric appendicitis. When a definitive interpretation was given, the accuracy was 96%, was independent of patient and system factors and resulted in reduced follow-up CTs and negative laparotomies. Accuracy can be increased by requiring the presence of periappendiceal inflammatory changes prior to interpreting a mildly distended appendix as positive for acute appendicitis. The indeterminate study rate can be reduced by not requiring visualization of the normal appendix for the exclusion of acute appendicitis.

To CT or not to CT? The influence of computed tomography on the diagnosis of appendicitis in obese pediatric patients

BACKGROUND

Appendicitis is a common pediatric query. However, obesity often results in nondiagnostic ultrasounds and increased likelihood of abdominal computed tomography (CT). Concern regarding radiation exposure led the Canadian Association of Radiologists to recommend foregoing CT when ultrasounds are nondiagnostic and clinical suspicion is high. We evaluated this recommendation by quantifying the influence of CT on the diagnosis of pediatric appendicitis.

METHODS

We performed a 2-year retrospective case series of children presenting with suspected appendicitis. We stratified patients by weight (obese v. nonobese) and pediatric appendicitis score (PAS) and examined how often they received abdominal CT, why they received it, and its influence on diagnosis.

RESULTS

Of 223 patients (84 obese, 139 nonobese), 54 received CT. Obese patients received CTs more frequently than nonobese patients (29% v. 22%). The most common reason for CT was a nondiagnostic ultrasound (75% in obese, 80% in nonobese patients). Sixty-five percent of CTs obtained after nondiagnostic ultrasounds confirmed the initial diagnosis, but the rates were 80% and 50%, respectively, when only obese and only nonobese patients were considered. Obese patients were 4 times more likely to have a CT confirming their initial appendicitis diagnosis.

CONCLUSION

Because obese patients are more likely than nonobese patients to have a CT that confirms appendicitis, when treating an obese pediatric patient with suspected appendicitis and a nondiagnostic ultrasound, surgeons with a high clinical suspicion should strongly consider foregoing CT and proceeding with treatment.

Abdominal wall thickness is not useful to predict appendix visualization on sonography in adult patients with suspected appendicitis

PURPOSE

To evaluate clinical and imaging factors for potential use in predicting appendix visualization on sonography (US) of adult patients with suspected appendicitis.

METHODS

All adult patients who underwent appendiceal US from January through June 2010 were included in this retrospective study. Clinicopathological records were reviewed for age, sex, weight, body mass index, symptom duration, Alvarado score, surgicopathologic diagnosis, and disposition. Imaging records were collated for abdominal thicknesses, appendix visualization, and impression. The definitive diagnosis was made on pathologic evaluation.

RESULTS

Eighty-six patients (68 women; median age, 35.5 years; age range, 16-86 years) met the inclusion criteria. The patients' mean weight was 56 kg; body mass index, 22.4; duration of symptoms, 24 hours; and Alvarado score, 6.5. Of the 86 patients, 37 (43%) had appendicitis. The appendix was visualized on US in 27 patients, of whom 25 had appendicitis; the appendix was not visualized in 59 patients, of whom 12 had appendicitis. There was no correlation between the clinical factors studied, the abdominal fat thickness (10.9 versus 10.7 mm; p = 0.90), or the abdominal wall thickness (16.9 versus 17.3 mm; p = 0.76) between patients with a US-visualized appendix and those whose appendix was not visualized on US.

CONCLUSIONS

Abdominal thicknesses and other factors are not predictive of appendix visualization on US examination of adults with suspected appendicitis.

Integration of ultrasound findings and a clinical score in the diagnostic evaluation of pediatric appendicitis

OBJECTIVE

To determine the predictive value of ultrasonography (US) for appendicitis in children when combined with clinical assessment based on the Pediatric Appendicitis Score (PAS).

STUDY DESIGN

Observational study of children aged 3-18 years who had an US examination for possible appendicitis. A PAS was calculated on the basis of historical elements, examination, and laboratory studies and was used to classify patients into 3 risk groups (low, medium, high). The predictive value of the PAS for appendicitis was calculated and stratified by the result of the US (positive, negative, or equivocal).

RESULTS

A total of 728 children with a median age 11.7 (IQR 7.8-14.9) years were studied; 29% had appendicitis. The negative predictive value of US decreased with increasing PAS-based risk assignment: low risk 1.00 (95% CI, 0.97-1.00), medium risk 0.94 (0.91-0.97), and high risk 0.81 (0.73-0.89). With increasing PAS, the positive predictive value increased: low risk 0.73 (0.47-0.99), medium risk 0.90 (0.82-0.98), and high risk 0.97 (0.95-1.0). Among children with equivocal ultrasound results, the proportion with appendicitis ranged from 0.09 (0.0-0.19) for low-risk patients to 0.47 (0.33-0.61) among for high-risk patients.

CONCLUSION

Ultrasound findings in children with possible appendicitis should be integrated with clinical assessment, such as a clinical score, to determine next steps in management. Rates of false-negative US increase with increasing PAS, and false-positive US results occur more often with lower PAS. When discordance exists between US results and the clinical assessment, serial examinations or further imaging are warranted.

Pediatric CT dose reduction for suspected appendicitis: a practice quality improvement project using artificial gaussian noise--part 2, clinical outcomes

OBJECTIVE. The purpose of this study was to determine the effect of a nominal 50% reduction in median absorbed radiation dose on sensitivity, specificity, and negative appendectomy rate of CT for acute appendicitis in children. MATERIALS AND METHODS. On the basis of a departmental practice quality improvement initiative using computer-generated gaussian noise for CT dose reduction, we applied a nominal dose reduction of 50% to abdominal CT techniques used for bowel imaging. This retrospective study consisted of 494 children who underwent a CT for suspected acute appendicitis before (n = 244; mean age, 133 months) and after (n = 250; mean age, 145 months) the nominal 50% dose reduction. Test performance characteristics of CT for acute appendicitis and impact on the negative appendectomy rate were compared for both time periods. Primary analyses were performed with histologic diagnosis as the outcome standard. Volume CT dose index and dose-length product were recorded from dose reports and size-specific dose estimates were calculated. RESULTS. The nominal 50% dose reduction resulted in an actual 39% decrease in median absorbed radiation dose. Sensitivity of CT for diagnosis of acute appendicitis was 98% (95% CI, 91-100%) versus 97% (91-100%), and specificity was 93% (88-96%) versus 94% (90-97%) before and after dose reduction, respectively. The negative appendectomy rate was 4.5% (0.8-10.25%) before dose reduction and 4.0% (0.4-7.6%) after dose reduction. CONCLUSION. The negative appendectomy rate and performance characteristics of the CT-based diagnosis of acute appendicitis were not affected by a 39% reduction in median absorbed radiation dose.

Use and accuracy of diagnostic imaging in the evaluation of pediatric appendicitis

BACKGROUND

There are safety concerns about the use of radiation-based imaging (computed tomography [CT]) to diagnose appendicitis in children. Factors associated with CT use remain to be determined.

METHODS

For patients ≤18 years old undergoing appendectomy, we evaluated diagnostic imaging performed, patient characteristics, hospital type, and imaging/pathology concordance (2008-2012) using data from Washington State's Surgical Care and Outcomes Assessment Program.

RESULTS

Among 2538 children, 99.7% underwent pre-operative imaging. 52.7% had a CT scan as their first study. After adjustment, age >10 years (OR 2.9 (95% CI 2.2-4.0), Hispanic ethnicity (OR 1.7, 95% CI 1.5-1.9), and being obese (OR 1.7, 95% CI 1.4-2.1) were associated with CT use first. Evaluation at a non-children's hospital was associated with higher odds of CT use (OR 7.9, 95% CI 7.5-8.4). Ultrasound concordance with pathology was higher for males (72.3 vs. 66.4%, p=.03), in perforated appendicitis (75.9 vs. 67.5%, p=.009), and at children's hospitals compared to general adult hospitals (77.3 vs. 62.2%, p<.001). CT use has decreased yearly statewide.

CONCLUSIONS

Over 50% of children with appendicitis had radiation-based imaging. Understanding factors associated with CT use should allow for more specific QI interventions to reduce radiation exposure. Site of care remains a significant factor in radiation exposure for children.

Point-of-care ultrasound in a patient with perforated appendicitis

We present the case of an 8-year-old girl with two emergency department visits for constipation and abdominal pain. Her medical history and physical examination noted by the emergency physician did not reveal a clear etiology of her symptoms until the second visit, when a point-of-care ultrasound was performed. The sonographic findings were consistent with a fecalith surrounded by fluid concerning for appendiceal rupture. A computerized tomographic scan of the abdomen confirmed these findings in addition to two large abscesses in the lower pelvis, which subsequently required percutaneous drainage. This case illustrates the utility of point-of-care ultrasound in the evaluation of the pediatric patient with abdominal pain when appendicitis is a concern, as well as the ability of the emergency physician to use this technology to guide treatment and care of pediatric patients.

False-negative appendicitis at ultrasound: nature and association

The objective was to describe nature and factors associated with false-negative ultrasound (US) for adult appendicitis. Patients with pathologically proven appendicitis and pre-operative US from January 2011 to May 2013 were included in this retrospective case-control study. They were divided into true-positive and false-negative groups, matched by age and gender. There were 112 patients (40 men, mean age = 40 y, 56 true positives) included. Two factors were found differ significantly: abdominal wall thickness and pain score. Greater abdominal wall thickness (18.6 mm vs. 14.9 mm, p = 0.001) and lower pain score (6.6 vs. 7.5, p = 0.018) were statistically associated with false negativity. The two groups did not differ significantly in terms of weight, height, body mass index, symptom duration, Alvarado score, US examination time, appendix position/size, perforation rate and operator. In conclusion, lower pain score and increased abdominal wall thickness are associated with false negativity in US examinations.

Does computed tomography have any additional value after sonography in patients with suspected acute appendicitis?

OBJECTIVES

The purpose of this study was to evaluate the additional value of supplementary computed tomography (CT) after sonography for diagnosing acute appendicitis.

METHODS

Among 140 consecutive patients with suspected acute appendicitis who underwent both initial sonography and supplementary CT within 12 hours, 88 patients whose appendices could not be visualized on sonography were excluded. The remaining 52 patients (mean age, 37.3 years; range, 15-98 years) were enrolled in this study. Two radiologists retrospectively reviewed the findings of 52 sonographic and CT examinations, and the appendix of each patient was classified as normal, equivocal appendicitis, nonperforated acute appendicitis, or perforated appendicitis. Causes of right lower quadrant pain other than appendicitis were also recorded. The additional value of supplementary CT was evaluated by performing head-to-head comparisons between CT and sonographic results.

RESULTS

No patients with a normal appendix on sonography showed appendicitis on CT. In addition, there were no patients with a sonographic diagnosis of appendicitis who had a normal appendix on CT. Ten patients (19.2%) were determined to have additional value gained from CT. Among these 10 patients, however, the additional information from CT affected treatment modality decisions in only 5.

CONCLUSIONS

Initial sonography can be as effective as CT in patients with suspected acute appendicitis when the results are definite. Supplementary CT should only be performed when sonography is inconclusive.

Appendicitis in obese children

During the past two decades, the incidence of childhood obesity has increased at alarming rates throughout the world. Obesity is associated with a variety of physiological changes that may impair a patient's response to surgery. With the rising rates of childhood obesity, pediatric surgeons must appreciate differences in the management and outcomes of these patients. Difficult physical examination, elevated inflammatory blood markers, and negative influence of obesity on the detection rate of the appendix on ultrasound have been reported causing diagnostic challenging of appendicitis in obese children. Moreover, obesity is associated with longer hospital stay and higher morbidity and minimal invasive techniques' superior outcomes over open technique in children undergoing appendectomy.