Imaging Utilization for the Diagnosis of Appendicitis in Stand-Alone Children's Hospitals in the United States: Trends and Costs

Ultrasound Diagnosis of Acute Appendicitis in Pediatrics: A Community Hospital Network Experience

Background Ultrasound has emerged as the preferred initial imaging modality for diagnosing acute appendicitis in children, but most data supporting its use come from academic children's medical centers. The purpose of this investigation is to describe ultrasound utilization for diagnosing acute appendicitis in children at a large community hospital network. Methods This was a multicenter retrospective observational cohort study and chart review of pediatric patients with acute appendicitis diagnosed in the emergency department (ED). The primary outcome of this study was the proportion of patients diagnosed with ultrasound as the sole imaging modality, presented as a population proportion with a 95% confidence interval. Results There were 450 patients included. The mean age was 10 years (range 3-17). Among the 450 patients, there were a total of 713 imaging studies. Only 213 (47.3%) patients had a single imaging test ordered during the ED encounter, and only 52 patients (11.6%) had an ultrasound during the encounter as the only imaging modality. The initial study ordered was a CT scan in 184 (40.9%), an ultrasound in 172 (38.2%), and an X-ray in 94 (20.9%). Sixty-two of 172 (36.0%) ultrasounds were positive for appendicitis. Of the 62 positive studies, 11 (17.7%) had a confirmatory CT scan. Conclusion In this community hospital network, patients had multiple imaging modalities ordered to confirm the diagnosis of acute appendicitis. Less than half had an ultrasound ordered as the initial imaging modality, suggesting its use is not as widespread as academic data may indicate. Despite a positive diagnostic ultrasound, some patients went on to have a confirmatory CT scan, which provides further opportunity to improve.

Identification of children with a nondiagnostic ultrasound at a low appendicitis risk using a pediatric Appendicitis Risk Calculator

OBJECTIVES

Up to 50% of ultrasounds (USs) for suspected pediatric appendicitis are nondiagnostic. While the validated low-risk clinical pediatric Appendicitis Risk Calculator (pARC) score < 15% and the low-risk US with nonvisualized appendix and no periappendiceal inflammation carry relatively low appendicitis risks, the contribution of the combination of both characteristics to this risk has never been assessed. The primary objective was to determine the proportion of children with the low-risk US-low-risk pARC combination with appendicitis. We hypothesized that this proportion would be 2.5% (upper 95% CI ≤ 5%).

METHODS

A retrospective cohort study of 448 previously healthy children 4-17 years old at a pediatric ED with suspected appendicitis, nondiagnostic US, and persistent clinical concern about appendicitis. Two investigators abstracted demographic, clinical, and imaging data. Based on published criteria, USs were classified as low-risk or high-risk. The pARC includes seven demographic, clinical, and laboratory variables and is quantified according to the published formula. The primary outcome was appendicitis, based on the histological evidence. All nonoperated patients underwent a 1-month-follow-up to exclude delayed appendicitis diagnoses.

RESULTS

Sixty of the 448 (13.4%) patients had appendicitis; 269 (60%) had low-risk US, 262 (58.4%) had low-risk pARC, and 163 (36.4%) had both characteristics. The appendicitis rates with low-risk pARC alone and low-risk US alone were 14/262 (5.4%) and 21/269 (7.8%), respectively. A total of 2/163 children (1.2%) with low-risk pARC and low-risk US had appendicitis (95% CI 0%-4.4%). Higher-risk US increased the appendicitis odds 5 (95% CI 1.54-20.55) to 11 times (95% CI 2.41-51.10) across pARC levels. The low-risk combination had sensitivity of 96.7% (95% CI 88.5%-99.6%), specificity of 41.5%, positive predictive value of 20.4%, and negative predictive value of 98.8% (95% CI 95.6%-99.9%).

CONCLUSIONS

The children with low-risk pARC and low-risk US combination are unlikely to have appendicitis and can be discharged home. The presence of higher-risk US-pARC score combinations substantially increases the appendicitis risk and warrants reassessment or interval imaging.

Failure to Significantly Reduce Radiation Exposure in Children with Suspected Appendicitis in the United States

BACKGROUND

Ultrasound (US) or magnetic resonance imaging (MRI) is recommended over computed tomography (CT) as the initial imaging modality when considering a diagnosis of appendicitis in children. This reduces unnecessary radiation exposure and has excellent accuracy. We hypothesized a significant increase in US utilization and a reduction in CT utilization in hospitals across the United States.

METHODS

We retrospectively reviewed NSQIP-P data from 2015 to 2021 for patients <18 years undergoing appendectomy for acute appendicitis. Rates of US, CT, and MRI usage were compared between NSQIP-P hospitals and referring non-NSQIP-P hospitals.

RESULTS

Of the 115,186 children included, 66,303 (57.6%) were imaged in NSQIP-P hospitals, 37,962 (33.0%) in non-NSQIP-P hospitals, and 7947 (6.9%) in both. US alone was used in 53.3%, followed by CT alone in 25.1%, both US + CT in 16.4%, and MRI ± CT/US in 2.6%. Non-NSIQP-P hospitals used less US than NSQIP-P centers (38.6% vs 90.8%, P < 0.0001) and more CT (74.0% vs 25.4%, P < 0.0001). From 2015 to 2021, overall US utilization increased from 68.5% to 72.3% (p < 0.0001) while CT utilization remained unchanged (43.1%-43.2%, P = 0.07). US use increased in non-NSQIP-P centers (18.8%-25.7%, P < 0.0001) but not in NSQIP-P (71.7% vs 70.9%, p = 0.28), while CT alone decreased in both (NSQIP-P: 10.1%-7.7%, P < 0.0001; non-NSQIP-P: 71.0%-59.8%, P < 0.0001).

CONCLUSION

US and MRI remain underutilized in diagnosing pediatric appendicitis, especially in non-NSQIP-P hospitals. Trends show modest increase in US utilization; however, CT alone remains a highly used modality in non-NSQIP-P hospitals. Adopting diagnostic strategies from NSQIP-P centers could optimize diagnostic imaging in children.

LEVEL OF EVIDENCE

III.

Imaging of Right Lower Quadrant Pain in Children and Adolescents: AJR Expert Panel Narrative Review

Right lower quadrant (RLQ) pain is a common clinical presentation in children, and accurate clinical diagnosis remains challenging given that this nonspecific presentation is associated with numerous surgical and nonsurgical conditions. The broad differential diagnosis varies by patient age and sex. Important considerations in the selection of a diagnostic imaging strategy include the sequencing, performance, and cost of tests. This article provides a comprehensive narrative review of the diagnostic imaging of RLQ pain in children and adolescents, including a discussion of the complementary roles of ultrasound, CT, and MRI; description of key imaging findings based on available evidence; and presentation of salient differential diagnoses. Subspecialized pediatric emergency medicine and surgical perspectives are also provided as further clinical insight into this common, but often challenging, scenario. Finally, the current status of imaging of RLQ pain in children and adolescents is summarized on the basis of expert consensus.

Advanced imaging use and payment trends in a large pediatric accountable care organization

BACKGROUND

Pediatric imaging use and payment trends in accountable care organizations (ACOs) are seldom studied but are important for health policy decisions and resource allocation.

OBJECTIVE

To evaluate patterns of advanced imaging use and associated payments over a 7-year period at a large ACO in the USA serving a Medicaid population.

MATERIALS AND METHODS

We reviewed paid claims data from 2011 through 2017 from an ACO, analyzing the MRI, CT and US use trends and payments from emergency department (ED) and outpatient encounters. We defined "utilization rate" as the number of advanced imaging procedures per 100 enrolled children per calendar year. Average yearly utilization and payments trends were analyzed using Pearson correlation.

RESULTS

Across 7 years, 186,552 advanced imaging procedures were performed. The average overall utilization rate was 6.99 (95% confidence interval [CI]: 6.9-7.1). In the ED this was 2.7 (95% CI: 2.6-2.8) and in outpatients 4.3 (95% CI: 4.2-4.3). The overall utilization rate grew by 0.7% yearly (P=0.077), with US growing the most at 4.0% annually (P=0.0005), especially in the ED in the US, where it grew 10.8% annually (P=0.000019). The overall payments were stable from 2011 to 2017, with outpatient MRI seeing the largest payment decrease at 1.8% (P=0.24) and ED US showing the most growth at 3.3% (P=0.00016). Head CT and abdominal US were the two most common procedures.

CONCLUSION

Over the study period, advanced imaging utilization at this large pediatric ACO serving the Medicaid population increased, especially with US use in the ED. Overall payments related to advanced imaging remained stable over this period.

Effect of Clinical Decision Support on Diagnostic Imaging for Pediatric Appendicitis: A Cluster Randomized Trial

IMPORTANCE

Appendicitis is the most common pediatric surgical emergency. Efforts to improve efficiency and quality of care have increased reliance on computed tomography (CT) and ultrasonography (US) in children with suspected appendicitis.

OBJECTIVE

To evaluate the effectiveness of an electronic health record-linked clinical decision support intervention, AppyCDS, on diagnostic imaging, health care costs, and safety outcomes for patients with suspected appendicitis.

DESIGN, SETTING, AND PARTICIPANTS

In this parallel, cluster randomized trial, 17 community-based general emergency departments (EDs) in California, Minnesota, and Wisconsin were randomized to the AppyCDS intervention group or usual care (UC) group. Patients were aged 5 to 20 years, presenting for an ED visit with right-sided or diffuse abdominal pain lasting 5 days or less. We excluded pregnant patients, those with a prior appendectomy, those with selected comorbidities, and those with traumatic injuries. The trial was conducted from October 2016 to July 2019.

INTERVENTIONS

AppyCDS prompted data entry at the point of care to estimate appendicitis risk using the pediatric appendicitis risk calculator (pARC). Based on pARC estimates, AppyCDS recommended next steps in care.

MAIN OUTCOMES AND MEASURES

Primary outcomes were CT, US, or any imaging (CT or US) during the index ED visit. Safety outcomes were perforations, negative appendectomies, and missed appendicitis. Costs were a secondary outcome. Ratio of ratios (RORs) for primary and safety outcomes and differences by group in cost were used to evaluate effectiveness of the clinical decision support tool.

RESULTS

We enrolled 3161 patients at intervention EDs and 2779 patients at UC EDs. The mean age of patients was 11.9 (4.6) years and 2614 (44.0%) were boys or young men. RORs for CT (0.94; 95% CI, 0.75-1.19), US (0.98; 95% CI, 0.84-1.14), and any imaging (0.96; 95% CI, 0.86-1.07) did not differ by study group. In an exploratory analysis conducted in 1 health system, AppyCDS was associated with a reduction in any imaging (ROR, 0.82; 95% CI, 0.73- 0.93) for patients with pARC score of 15% or less and a reduction in CT (ROR, 0.58; 95% CI, 0.45-0.74) for patients with a pARC score of 16% to 50%. Perforations, negative appendectomies, and cases of missed appendicitis by study phase did not differ significantly by study group. Costs did not differ overall by study group.

CONCLUSIONS AND RELEVANCE

In this study, AppyCDS was not associated with overall reductions in diagnostic imaging; exploratory analysis revealed more appropriate use of imaging in patients with a low pARC score.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02633735.

Trends in Use of Advanced Imaging in Pediatric Emergency Departments, 2009-2018

Importance

There is increased awareness of radiation risks from computed tomography (CT) in pediatric patients. In emergency departments (EDs), evidence-based guidelines, improvements in imaging technology, and availability of nonradiating modalities have potentially reduced CT use.

Objective

To evaluate changes over time and hospital variation in advanced imaging use.

Design, Setting, and Participants

This cross-sectional study assessed 26 082 062 ED visits by children younger than 18 years from the Pediatric Health Information System administrative database from January 1, 2009, through December 31, 2018.

Exposures

Imaging.

Main Outcomes and Measures

The primary outcome was the change in CT, ultrasonography, and magnetic resonance imaging (MRI) rates from January 1, 2009, to December 31, 2018. Imaging for specific diagnoses was examined using all patient-refined diagnosis related groups. Secondary outcomes were hospital admission and 3-day ED revisit rates and ED length of stay.

Results

There were a total of 26 082 062 visits by 9 868 406 children (mean [SD] age, 5.59 [5.15] years; 13 842 567 [53.1%] male; 9 273 181 [35.6%] non-Hispanic white) to 32 US pediatric EDs during the 10-year study period, with 1 or more advanced imaging studies used in 1 919 283 encounters (7.4%). The proportion of ED encounters with any advanced imaging increased from 6.4% (95% CI, 6.2%-6.2%) in 2009 to 8.7% (95% CI, 8.7%-8.8%) in 2018. The proportion of ED encounters with CT decreased from 3.9% (95% CI, 3.9%-3.9%) to 2.9% (95% CI, 2.9%-3.0%) (P < .001 for trend), with ultrasonography increased from 2.5% (95% CI, 2.5%-2.6%) to 5.8% (95% CI, 5.8%-5.9%) (P < .001 for trend), and with MRI increased from 0.3% (95% CI, 0.3%-0.4%) to 0.6% (95% CI, 0.6%-0.6%) (P < .001 for trend). The largest decreases in CT rates were for concussion (-23.0%), appendectomy (-14.9%), ventricular shunt procedures (-13.3%), and headaches (-12.4%). Factors associated with increased use of nonradiating imaging modalities included ultrasonography for abdominal pain (20.3%) and appendectomy (42.5%) and MRI for ventricular shunt procedures (17.9%) (P < .001 for trend). Across the study period, EDs varied widely in the use of ultrasonography for appendectomy (median, 57.5%; interquartile range [IQR], 40.4%-69.8%) and MRI (median, 15.8%; IQR, 8.3%-35.1%) and CT (median, 69.5%; IQR, 54.5%-76.4%) for ventricular shunt procedures. Overall, ED length of stay did not change, and hospitalization and 3-day ED revisit rates decreased during the study period.

Conclusions and Relevance

This study found that use of advanced imaging increased from 2009 to 2018. Although CT use decreased, this decrease was accompanied by a greater increase in the use of ultrasonography and MRI. There appears to be substantial variation in practice and a need to standardize imaging practices.

Value Assessment of Evolving Pediatric Appendicitis Imaging Strategies Between 2004 and 2018

OBJECTIVE

To assess diagnostic imaging utilization and the proportion of negative appendectomies for pediatric appendicitis at US children's hospitals between 2004 and 2018.

METHODS

This was a retrospective study using data from the Pediatric Health Information System (PHIS) database. Pediatric patients (age: 0-17 years) who underwent an appendectomy at one of 32 children's hospitals from January 1, 2004, through September 30, 2018, were included. Patients were identified based on International Classification of Diseases, 9th revision and International Classification of Diseases, 10th revision procedure codes. Patient demographics, imaging performed, and the frequency of negative appendectomy were analyzed.

RESULTS

The final study population consisted of 104,033 children. From 2004 to 2018, CT utilization decreased from 56.8% (2,951 of 5,198) to 18.6% (1,201 of 6,455; P < .001). Ultrasound utilization increased from 26.4% (1,371 of 5,198) to 63.4% (4,093 of 6,455; P < .001). Radiography utilization remained stable at 16.7% (870 of 5,198) and 15.8% (1,018 of 6,455; P = .160). MRI use increased from 0.1% (6 of 5,198) to 2.2% (143 of 6,455; P < .001). During the study period, the negative appendectomy rate slightly decreased, from 3.74% (4,742 of 126,778 in 2004-2011) to 3.14% (4,258 of 135,561 in 2012-2018; P < .001).

CONCLUSION

There has been a shift in imaging of children with appendicitis over 15 years in the United States, because the use of CT has decreased and ultrasound use has increased. This shift has likely added value to the health care system without adversely affecting outcomes (negative appendectomy rate).

Accuracy of unenhanced, non-sedated MRI in the diagnosis of acute appendicitis in children

BACKGROUND

Children with suspected appendicitis generally undergo an ultrasound (most commonly) or a CT scan (rarely) as the first imaging study. At our hospital, patients with non-diagnostic ultrasound or CT scan results undergo a non-contrast (unenhanced), non-sedated MRI. We aimed to determine the accuracy of this study for this purpose in a large cohort of children.

METHODS

A retrospective review of all unenhanced, non-sedated MRIs done for suspected appendicitis was performed from January 2014 to December 2018. MRI reports were correlated with pathology reports in cases that underwent appendectomy, and with clinical outcomes if no operation was done (clinical follow up: 30d). No patient was treated for appendicitis non-operatively.

RESULTS

Three hundred fifty unenhanced, non-sedated MRIs were done and reviewed with median age: 12 (3 to 18) years. Sixty-five (18.6%) MRIs were positive for appendicitis, and 62 of those underwent appendectomy (3 excluded clinically). Pathology was positive in 59/62 cases. 256 (73.1%) MRIs were negative for appendicitis. Six cases underwent appendectomy (persistent symptoms). Pathology was positive in 2/6 cases. The overall diagnostic accuracy was: sensitivity 96.7% (95% CI: 88.6-99.6), specificity 97.7% (95% CI: 95.0-99.1), PPV: 90.8% (95% CI: 81.6-95.6; false positives 6/65), and NPV: 99.2% (95% CI: 97.0-99.8; false negatives 2/254). Twenty-nine (8.3%) MRIs were non-diagnostic. None of those 29 cases had appendicitis (4 negative pathology, 25 excluded clinically).

CONCLUSIONS

The unenhanced, non-sedated MRI is highly accurate for the diagnosis of appendicitis in children. It should be considered as an alternative to CT in the work-up of patients with suspected appendicitis to eliminate the risks associated with ionizing radiation.

LEVEL OF EVIDENCE

Level IV.

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.

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.

Diagnosis of appendicitis in the paediatric emergency department: an update

PURPOSE OF REVIEW

Concern regarding appendicitis is a common reason for presentation to the paediatric emergency department. We review recent progress in the use of biomarkers, imaging and clinical scoring systems in improving diagnostic accuracy in suspected appendicitis in children.

RECENT FINDINGS

Use of ultrasound, often performed at the bedside, is becoming more widespread with a parallel reduction in computed tomography (CT) use. Protocols for image acquisition and interpretation have been shown to improve diagnostic accuracy. Novel biomarkers have been explored and clinical diagnostic algorithms refined but none have achieved the level of diagnostic accuracy required.

SUMMARY

Appendicitis remains a clinical diagnosis. Point of care ultrasound is increasingly available and offers higher diagnostic accuracy than several routinely performed laboratory investigations. Recent publications provide support for increased use of clinician performed ultrasound, increased use of MRI, less use of CT, less emphasis on basic laboratory investigation and a renewed respect for the value of serial examination, particularly early in the course of illness.

Hospital type predicts computed tomography use for pediatric appendicitis

BACKGROUND

Evidence-based guidelines recommend ultrasound (US) over computed tomography (CT) as the primary imaging modality for suspected pediatric appendicitis. Continued high rates of CT use may result in significant unnecessary radiation exposure in children. The purpose of this study was to evaluate variables associated with preoperative CT use in pediatric appendectomy patients.

METHODS

A retrospective cohort study of pediatric patients who underwent appendectomy for acute appendicitis in 2015-2016 at National Surgical Quality Improvement Program for Pediatrics (NSQIP-P) hospitals was conducted. Pediatric (<18 years old) patients who underwent appendectomy for acute appendicitis in an NSQIP-P hospital from 2015 to 2016 were included. Patients were excluded if they underwent interval or incidental appendectomy or did not have a final diagnosis of appendicitis. Variables associated with imaging evaluation, including age, body mass index (BMI), race/ethnicity, gender and hospital of presentation (NSQIP-P vs. non-NSQIP-P hospital) were evaluated. The primary outcome was receipt of preoperative CT. Secondary outcomes include reimaging practices and trends over time.

RESULTS

22,333 children underwent appendectomies, of which almost all were imaged preoperatively (96.5%) and 36% of whom presented initially to a non-NSQIP-P hospital. Overall, US only was the most common imaging modality (52%), followed by CT only (27%), US+CT (16%), no imaging (3%), MRI +/- CT/US (1%) and MRI only (<1%). On regression, older age (>11 years), obesity (BMI >95th percentile for age), and female gender were associated with increased odds of receiving a CT scan. However, initial presentation to a non-NSQIP-P hospital was the strongest predictor of CT use (OR 9.4, 95% CI 8.1-10.8). Reimaging after transfer was common, especially after US and MRI at a non-NSQIP-P hospital. CT use decreased between 2015 and 2016 in non-NSQIP-P hospitals but remained the same (25%) in NSQIP-P facilities.

CONCLUSIONS

Though patient characteristics were associated with different imaging practices, presentation at a referral, nonchildren's hospital is the strongest predictor of CT use in children with appendicitis. NSQIP-P hospitals frequently reimage transferred patients and have not reduced their CT use. Novel strategies are required for all hospital types in order to sustain reduction in CT use and mitigate unnecessary imaging.

LEVEL OF EVIDENCE

Level III.

TYPE OF STUDY

Retrospective comparative study.

Paediatric appendiceal ultrasound: a survey of Australasian sonographers' opinions on examination performance and sonographic criteria

INTRODUCTION

The objectives of this study were to identify knowledge gaps and/or perceived limitations in the performance of paediatric appendiceal ultrasound by Australasian sonographers. We hypothesised that: sonographers' confidence in visualising the appendix in children was poor, particularly outside predominantly paediatric practice; workplace support for prolonging examinations to improve visualisation was limited; and the sonographic criteria applied in diagnosis did not reflect contemporary literature.

METHODS

A cross-sectional survey of Australasian sonographers regarding paediatric appendicitis was conducted using a mixed methods approach (quantitative and qualitative data). Text responses were analysed for key themes, and quantitative data analysed using chi-square, Mann-Whitney U and Wilcoxon signed-rank tests.

RESULTS

Of the 124 respondents, 27 (21.8%) reported a visualisation rate of less than 10%. Workplace support for extending examination time was significantly related to a higher appendix visualisation rate (χ2 (2) = 16.839, P < 0.001). Text responses reported frustration locating the appendix and a desire for more time and practice to improve visualisation. Sonographers suggested a significantly lower maximum diameter cut-off in a 5-year-old compared to a 13-year-old (Z = -6.07, P < 0.001), and considered the presence of inflamed peri-appendiceal mesentery as the most useful sonographic criterion in diagnosing acute appendicitis.

CONCLUSIONS

Respondents had a low opinion of their ability to confidently identify the appendix. Confidence was greater in those centres where extending scanning time was encouraged. Application of echogenic mesentery as the most significant secondary sonographic criterion is supported by recent studies. Opinions of diameter cut-offs varied, indicating potential for improved awareness of recent research.

MRI for Pediatric Appendicitis in an Adult-Focused General Hospital: A Clinical Effectiveness Study-Challenges and Lessons Learned

OBJECTIVE

The objective of our study was to determine the feasibility and accuracy of MRI for pediatric appendicitis in an adult-predominant general hospital setting where non-pediatric-trained radiologists routinely interpret the studies.

MATERIALS AND METHODS

MRI was performed in pediatric patients with equivocal ultrasound (US) findings and persistent clinical concern for appendicitis. Neither IV contrast material nor a sedative was administered. Our MRI protocol evolved early during the study period, quickly settling on three sequences (total scanning time, 11 minutes). The clinical reference standard for statistical analysis was appendicitis diagnosed on operative or pathology report; 95% Clopper-Pearson CIs were calculated.

RESULTS

Between 2012 and 2016, 528 pediatric patients (mean age, 9.9 years; age range, 1-17 years) underwent MRI after US evaluation yielded equivocal findings: 10.4% (55/528) of patients were found to have surgically proven or pathologically proven appendicitis. Sensitivity and specificity of MRI for appendicitis were 96.4% and 98.9%, respectively. Positive and negative predictive values were 91.2% and 99.6%. A normal appendix and abnormalities not involving the appendix were identified on MRI in 21.6% (114/528) of patients.

CONCLUSION

Our data show that unenhanced MRI for suspected appendicitis in pediatric patients is clinically effective when performed in a nonpediatric hospital setting with nonpediatric radiologists, emergency physicians, and surgeons.

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.

Standardized reporting of appendicitis-related findings improves reliability of ultrasound in diagnosing appendicitis in children

PURPOSE

Our objective was to increase ultrasound reliability for diagnosing appendicitis in an academic children's hospital emergency department (ED) through a multidisciplinary quality improvement initiative.

METHODS

A retrospective review of ultrasound use in patients diagnosed with appendicitis in our ED from 1/1/2011 to 6/30/2014 established a baseline cohort. From 8/1/2014 to 7/31/2015 a diagnostic algorithm that prioritized ultrasound over CT was used in our ED, and a standardized template was implemented for the reporting of appendicitis-related ultrasound findings by our radiologists.

RESULTS

Of 627 patients diagnosed with appendicitis in the ED during the retrospective review, 46.1% (n=289) had an ultrasound. After implementation of the diagnostic algorithm and standardized ultrasound report, 88.4% (n=236) of 267 patients diagnosed with appendicitis had an ultrasound (p<0.01). The frequency of indeterminate results decreased from 44.3% to 13.1%, and positive results increased from 46.4% to 66.1% in patients with appendicitis (p<0.01). The sensitivity of ultrasound (indeterminate counted as negative) increased from 50.6% to 69.2% (p<0.01).

CONCLUSIONS

Ultrasound reliability for the diagnosis of appendicitis in children can be improved through standardized results reporting. However, these changes should be made as part of a multidisciplinary quality improvement initiative to account for the initial learning curve necessary to increase experience.

LEVEL OF EVIDENCE

Level II, Study of Diagnostic Test.

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.