Performance of MRI for suspected appendicitis in pediatric patients and negative appendectomy rate: A systematic review and meta-analysis

Quality Improvement Campaign Improved Utilization of Rapid Sequence MRI for Diagnosis of Pediatric Appendicitis

INTRODUCTION

Appendicitis is the most common indication for emergency general surgery in the pediatric population. Computed tomography (CT) or magnetic resonance imaging (MRI) may be used for diagnosis when ultrasound findings are equivocal. However, CT involves unnecessary radiation exposure if MRI is available. After introducing a rapid sequence MRI (rsMRI) appendicitis protocol at our institution, CT was still preferentially used. We therefore implemented a quality improvement (QI) campaign to reduce the rate of CTs and increase the rate of rsMRI. Here, we assess the effectiveness of the QI campaign while evaluating potential barriers to using rsMRI.

METHODS

We conducted a mixed methods study, first performing stakeholder interviews which informed the design of a QI campaign initiated in May 2021 and a midway feedback survey in December 2021. A retrospective cohort study was then performed of children evaluated for appendicitis at our institution between January 1, 2016, and April 30, 2022. CT and rsMRI rates were compared before and after QI campaign implementation.

RESULTS

There was a significant decrease in rate of CTs and increase in rate of rsMRIs performed following the initiation of the QI campaign (p < 0.0001). The rate of CT scans decreased by a factor of 0.4 while the rate of rsMRI increased by a factor of 9.5.

CONCLUSION

A successful QI campaign was initiated at our institution, resulting in decreased utilization of CT and increased use of rsMRI for the evaluation of suspected appendicitis. These results highlight the potential impact of QI projects.

LEVEL OF EVIDENCE

III.

Implementation of ultrasound and fast magnetic resonance imaging pathway reduces computed tomography utilization in children with suspected appendicitis

PURPOSE

Computed tomography (CT) is still used in the imaging diagnosis of acute appendicitis in children at many hospitals. We implemented an ultrasound (US) and fast magnetic resonance imaging (MRI) pathway for suspected appendicitis at our institution with the goal of reducing radiation exposure in children.

METHODS

All children (< 18 years old) who underwent appendectomy between January 2011 and July 2021 were reviewed. Data were collected on all imaging studies performed. In December 2015, we initiated an imaging pathway for suspected acute appendicitis. US was the initial imaging study, and a rapid protocol MRI was performed if US was equivocal. Those could not tolerate MRI underwent CT. We evaluated the difference in percentage of patients who underwent CT before and after pathway initiation.

RESULTS

554 patients who underwent appendectomy did not have prior imaging studies on presentation to our hospital and were included in analysis. After initiating the pathway, the use of abdominal US increased from 87% (220 of 254) to 97% (291 of 300, p < 0.0001) and the use of MRI increased by 100% (0 MRIs pre-protocol, 90 of 300 patients post-protocol, p < 0.0001). CT utilization decreased significantly from 32% (82 of 254) to 2% (6 of 300, p < 0.0001).

CONCLUSION

Embracing a new US and rapid MRI pathway to evaluate pediatric patients with suspected acute appendicitis resulted in significant reduction in CT utilization and therefore radiation exposure.

The role of the neutrophil-to-lymphocyte ratio in avoiding negative appendectomies

INTRODUCTION

The neutrophil-to-lymphocyte ratio (NLR) is an inflammatory biomarker that is easily calculated with data from the differential white blood cell count. The aim of our study was to analyse the role of the NLR in the detection of negative appendectomies and to compare its usefulness with other clinical, sonographic and laboratory factors previously described.

METHODS

We conducted a retrospective study in patients aged less than 16 years who underwent appendectomy in our hospital between 2017 and 2020. We divided patients into 2 groups based on appendiceal histological findings: NA group (negative appendicitis: absence of appendiceal inflammation) and PA group (positive appendicitis: presence of inflammation in any layer of the appendiceal wall). We analysed demographic, clinical, sonographic and laboratory characteristics.

RESULTS

We included a total of 1269 patients, 1244 in the PA group and 25 in the NA group, with no differences between groups in demographic characteristics. The proportion of patients that presented with nausea and vomiting was significantly smaller in the NA group compared to the PA group (P < .001), and there were no other differences in symptoms. The appendiceal diameter on ultrasound was significantly smaller in the NA group (8.1 ± 2.1 vs. 9.7 ± 2.8 mm; P < .001). The white blood cell and neutrophil counts and the NLR were significantly higher in the PA group (P < .001), as was the level of C-reactive protein (18.6 vs. 2.6; P = .005). The ROC curve analysis revealed that the NLR was the parameter with the highest AUC (0.879) for the diagnosis of negative appendicitis, with a cut-off point of 2.65 for a maximum sensitivity of 84.2% and specificity of 83.8%.

CONCLUSION

The NLR is the preoperative parameter that best discriminates patients without acute appendicitis. Values of less than 2.65 should make clinicians contemplate diagnoses other than appendicitis.

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

Background

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

Results

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

Conclusion

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

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.

Increase in Pediatric Perforated Appendicitis in the New York City Metropolitan Region at the Epicenter of the COVID-19 Outbreak

OBJECTIVE

The aim of the study was to determine whether perforated appendicitis rates in children were influenced by the Coronavirus disease 2019 (COVID-19) surge.

BACKGROUND

Disruption of care pathways during a public health crisis may prevent children from obtaining prompt assessment for surgical conditions. Progression of appendicitis to perforation is influenced by timeliness of presentation. In the context of state-mandated controls and public wariness of hospitals, we investigated the impact of the COVID-19 outbreak on perforated appendicitis in children.

STUDY DESIGN

We conducted an analysis of all children presenting to 3 hospital sites with acute appendicitis between March 1 and May 7, 2020, corresponding with the peak COVID-19 outbreak in the New York City region. Control variables were collected from the same institutions for the preceding 5 years. The primary outcome measure was appendiceal perforation.

RESULTS

Fifty-five children presented with acute appendicitis over 10 weeks. Compared to a 5-year control cohort of 1291 patients, we observed a higher perforation rate (45% vs 27%, odds ratio 2.23, 95% confidence interval 1.29-3.85, P = 0.005) and longer mean duration of symptoms in children with perforations (71 ± 39 vs 47 ± 27 h, P = 0.001) during the COVID-19 period. There were no differences in perforation rates (55% vs 59%, P = 0.99) or median length of stay (1.0 vs 3.0 days, P = 0.58) among children screening positive or negative for SARS-CoV-2.

CONCLUSIONS

Children in the epicenter of the COVID-19 outbreak demonstrated higher rates of perforated appendicitis compared to historical controls. Preoperative detection of SARS-CoV-2 was not associated with inferior outcomes. Although children likely avoid much of the morbidity directly linked to COVID-19, disruption to local healthcare delivery systems may negatively impact other aspects of pediatric surgical disease.

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

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

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.

The Impact of Pathological Criteria on Pediatric Negative Appendectomy Rate

INTRODUCTION

Negative appendectomy rate (NAR) is a quality metric used in the surgical management of appendicitis. The rates of negative appendectomy (NA) in children range anywhere from 1% to 40% in the literature. Many reports do not provide clear pathological definitions for either appendicitis or NA on which they base their calculation of NAR. We reviewed our experience with pediatric appendectomy and the pathological spectrum encompassed within our definition of a NA and examined how the pathologic definition impacts our hospital's NAR.

METHODS

A retrospective review from 2012 to 2016 in a single institution identified 1676 children that underwent appendectomy. Average age was 11.4 (2-18 years). Patient demographics, clinical outcomes and pathological findings were collected. At our institution, appendicitis is defined as the presence of transmural acute inflammation in the appendix and those patients without this finding have been considered to have had a negative appendectomy.

RESULTS

1435 patients underwent appendectomy for presumed appendicitis. The rate of pathologically diagnosed appendicitis was 91.1% (1307/1435) and as such, the NAR was 8.9% (128/1435). Review of the pathology of the NA cohort identified 67/128 (52.3%) patients with completely normal pathology. The remaining 61 patients displayed some sort of pathological abnormality including malignancy (n = 2), fecaliths (n = 9), pinworms (n = 3), granuloma (n = 2), fibrous obliteration (n = 4), isolated periappendiceal inflammation (n = 1), and acute inflammation confined to the mucosa (n = 40). Exclusion of these patients with abnormal pathology decreased the NAR to 4.6%. Patients with pathological abnormalities of the appendix other than transmural inflammation had a higher rate of 30-day readmission than patients with acute appendicitis (8.2% versus 4.5% p < 0.01).

CONCLUSION

Pediatric NAR is dependent upon the pathological definition of appendicitis and negative appendectomy. Institutional variation in definition may explain discrepancies in the literature. By example, including only those that show "the absence of inflammation or other appendiceal pathology" would decrease our NAR by 50%. This study calls into question the interpretation of interhospital NAR and the use of NAR as a quality metric in the management of appendicitis. Retrospective comparative study: Level III evidence.

Perforation risk in pediatric appendicitis: assessment and management

Perforated appendicitis, as defined by a visible hole in the appendix or an appendicolith free within the abdomen, carries significant morbidity in the pediatric population. Accurate diagnosis is challenging as there is no single symptom or sign that accurately predicts perforated appendicitis. Younger patients and those with increased duration of symptoms are at higher risk of perforated appendicitis. Elevated leukocytosis, bandemia, high C-reactive protein, hyponatremia, ultrasound, and CT are all useful tools in diagnosis. Distinguishing patients with perforation from those without is important given the influence of a perforation diagnosis on the management of the patient. Treatment for perforated appendicitis remains controversial as several options exist, each with its indications and merits, illustrating the complexity of this disease process. Patients may be managed non-operatively with antibiotics, with or without interval appendectomy. Patients may also undergo appendectomy early in the course of their index hospitalization. Factors known to predict failure of non-operative management include appendicolith, leukocytosis greater than 15,000 white blood cells per microliter, increased bands, and CT evidence of disease beyond the right lower quadrant. In this review, the indications and benefits of each treatment strategy will be discussed and an algorithm to guide treatment decisions will be proposed.

Visibility of Normal Appendix on CT, MRI, and Sonography: A Systematic Review and Meta-Analysis

OBJECTIVE

The purpose of the present study is to assess the visibility of the normal appendix on CT, MRI, or ultrasound (US) images of a healthy population.

MATERIALS AND METHODS

The MEDLINE and EMBASE databases were searched to identify articles on the rates of detection of a normal appendix on CT, MRI, or US that appeared in the literature published up to January 20, 2017. Pooled detection rates were assessed using random-effects modeling, and rates associated with different imaging modalities were compared. Meta-regression analyses were performed to assess factors influencing detection rates and heterogeneity.

RESULTS

Thirty-two studies (21 CT studies with 5296 patients, 7 MRI studies with 600 patients, and 4 US studies with 1221 patients) were included in our meta-analysis. The overall normal appendix detection rate tended to be highest for CT (84%), followed by US (71%) and MR (69%), but no statistically significant differences were noted (for CT vs MRI, p = 0.16; for CT vs US, p = 0.23; and for MRI vs US, p = 0.91). Meta-regression analyses of the appendix detection rate with CT revealed that the year of publication of the study, the number of CT channels, and slice thickness affected study heterogeneity.

CONCLUSION

Normal appendixes seemed to be more visible on CT than on MRI or US, although this finding did not have statistical significance. With respect to CT, detection of normal appendixes was significantly better when more channels and thinner slices were used.