The current utility of ultrasound in the diagnosis of acute appendicitis

Risk factors for acute appendicitis among adult patients with indeterminate ultrasound

OBJECTIVES

Abdominal ultrasound is used for diagnosing appendicitis in patients with right lower quadrant abdominal pain. Between 45 and 82% of radiology performed ultrasounds are indeterminate for appendicitis and computed tomography is required for diagnostic confirmation. Our study aims to determine predictors to rule out appendicitis when ultrasound is indeterminate.

METHODS

We performed a health records review of adult emergency department (ED) patients presenting with symptoms suspicious for appendicitis and indeterminate ultrasound to two academic EDs between June 2019 and July 2020. The outcome was appendicitis diagnosis within 30 days of the index ED visit. We used multivariable logistic regression, identifying a cut-off threshold for continuous variables with cubic spline, and chose the parsimonious model to develop a binary decision rule. We report Odds ratios (OR) and diagnostic performance with 95% confidence intervals (CI).

RESULTS

Overall, 463 patients (mean age 30.3 years (SD 10.5 years), 74.9% female) were included. Appendicitis was diagnosed in 45 patients (9.7% [95% CI 7.2-12.8%]). After ultrasound, computed tomography was performed in 227 patients (49.0%) and 39 patients (17.2%) were diagnosed with appendicitis. Among the 236 patients who did not have a subsequent computed tomography, 6 (2.6%) patients had appendicitis. Neutrophil count > 5.5 × 109/L (OR 1.21 [95% CI 1.12-1.30]) and secondary signs of inflammation on ultrasound (OR 2.16 [1.07-4.37]) were associated with a higher likelihood of appendicitis (C-statistic 0.77 [95% CI 0.70-0.84]). The absence of both predictors had a sensitivity of 88.9% (95% CI 76.0-96.3%), specificity of 45.7% (95% CI 40.8-50.6%) and a negative predictive value of 0.97 (95% CI 0.94-0.99) to rule out appendicitis.

CONCLUSION

For patients suspected of appendicitis and indeterminate ultrasound, the absence of an elevated neutrophil count and secondary signs of inflammation are associated with a low probability of appendicitis.

ACR Appropriateness Criteria® Acute Pelvic Pain in the Reproductive Age Group: 2023 Update

This review focuses on the initial imaging in the reproductive age adult population with acute pelvic pain, including patients with positive and negative beta-human chorionic gonadotropin (β-hCG) levels with suspected gynecological and nongynecological etiology. For all patients, a combination of transabdominal and transvaginal pelvic ultrasound with Doppler is usually appropriate as an initial imaging study. If nongynecological etiology in patients with negative β-hCG is suspected, then CT of the abdomen and pelvis with or without contrast is also usually appropriate. In patients with positive β-hCG and suspected nongynecological etiology, CT of the abdomen and pelvis with contrast and MRI of the abdomen and pelvis without contrast may be appropriate. In patients with negative β-hCG and suspected gynecological etiology, CT of the abdomen and pelvis with contrast, MRI of pelvis without contrast, or MRI of pelvis with and without contrast may be appropriate. 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 process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

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.

ACR Appropriateness Criteria® Right Lower Quadrant Pain: 2022 Update

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

The utility of spectral Doppler evaluation of acute appendicitis

PURPOSE

The use of spectral Doppler, peak systolic velocity (PSV), and resistive index (RI) imaging criteria to improve the accuracy of acute appendicitis diagnosis is hypothesized.

METHODS

Graded compression ultrasound was performed for suspected patients. The spectral Doppler evaluation was conducted while observing the appendix. A total of 152 patients (82 males and 70 females, ages 4-63 years, mean age of 24.5 years) were examined using the spectral Doppler waveform between 2018 and 2019. RI and PSV values of patients with and without appendicitis were compared to histopathologic findings. SPSS 26 was used to analyze the data, including using descriptive statistics and measures of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

RESULTS

Appendicitis was confirmed in 95 patients (62.5%) and rejected in 57 patients (37.5%). For the diagnosis of appendicitis, the area under the curve (AUC) of receiver operating characteristic (ROC) for RI (0.92 with 95% confidence interval (CI): 0.88, 0.97; P = 0.001) and PSV (0.96, with 95% CI: 0.93, 1.00; P = 0.001) was calculated. The discriminatory RI ≥ 0.49 demonstrated high sensitivity (90.5%) and low specificity (86%), and the discriminatory PSV ≥ 9.6 cm/s had high specificity (94.7%) and sensitivity (94.7%) for appendicitis.

CONCLUSION

By incorporating spectral Doppler criteria into routine graded compression ultrasound, the diagnostic accuracy of acute appendicitis was increased. In comparison, high PSV and RI values of the appendix with a cut-off point of 9.6 cm/s and 0.49 differ significantly between positive and negative appendectomy patients.

Diagnostic performance of US for suspected appendicitis: Does multi-categorical reporting provide better estimates of disease in adults, and what factors are associated with false or indeterminate results?

PURPOSE

To identify factors associated with false or indeterminate US result for suspected appendicitis, and assess whether multi-categorical reporting of US yields more precise estimates regarding the probability of appendicitis.

METHODS

562 US examinations for suspected appendicitis between May 2013-April 2015 were categorized as true (77/562 true positives or true negatives) or false/indeterminate (485/562 false negatives, false positives or indeterminates) based on results from a prior study. Of 541 examinations with images available retrospectively, a category of A-E was assigned as follows: non-visualized appendix with secondary findings (A) absent or (B) present; appendix visualized and considered (C) negative, (D) equivocal, or (E) positive for appendicitis. The following factors were recorded: age; sex; scan time (daytime vs. off-hours); resident/fellow involvement; abdominal subspecialty radiologist; radiologist experience (>5 years or not); and tenderness on interrogation. Associations between factors and US result were assessed (t-tests, Fisher's exact test and multivariate logistic regression).

RESULTS

The true group had proportionally more males (18/77 (23.4%) vs. 66/485 (13.6%), p = 0.04) and patients with sonographic tenderness (43/77 (55.8%) vs. 132/353 (27.3%), p < 0.0001). There was no significant difference or association with other factors. On multivariate logistic regression, false/indeterminate results were 1.9 times (95% CIs 1.0-3.5) more likely among females and 3.8 times more likely in the absence of tenderness (95% CIs 2.3-6.4). The proportion of patients with appendicitis in categories A-E was 34/410 (8.3%), 24/44 (54.5%), 0/18 (0%), 0/3 (0%) and 61/66 (92.4%), respectively.

CONCLUSIONS

Females and absence of tenderness were associated with a false/indeterminate US. Categorical reporting provides more granular estimates of the post-test probability of appendicitis.

Ultrasound for Suspected Acute Appendicitis in Adult Women Under Age 40: An Evaluation of On-Call Radiology Resident Scanning

RATIONALE AND OBJECTIVES

At our institution, on-call radiology residents perform emergent ultrasounds (US) outside of departmental working hours. The aim of the study was to evaluate radiology resident-performed US for clinically suspected acute appendicitis in women under the age of 40.

MATERIALS AND METHODS

Retrospective review of 104 consecutive US scans outside of departmental working hours by radiology residents, and 104 consecutive US studies scanned during departmental working hours by sonographers, in women under the age of 40 for clinically suspected appendicitis .

RESULTS

Appendix visualization rate was 27% for the resident group (sonographer group: 30%, p = 0.759). The sensitivity and specificity of US for appendicitis were 63% (95% confidence interval: 41%-81%) and 98% (95% CI: 91%-100%), respectively for the resident group (sonographer group: 69% [95% CI: 41%-89 %] and 98% [95% CI: 92%-100%], respectively). An alternative cause for right lower quadrant pain was offered in 17% of resident group cases (sonographer group: 21%, p = 0.598). Follow-up CT or MRI was performed in 47% of resident cases (sonographer group: 44%, p = 0.781). Residents performed more focused US (i.e. not imaging the pelvic organs), at 34% (sonographer group: 1%, p < 0.001). When only focused scanning was performed by residents, there was a trend toward increased downstream imaging (CT or MRI), odds ratio = 2.76 (95% CI: 0.99-7.70).

CONCLUSIONS

Out-of-hours US scans performed by radiology residents had similar performance characteristics compared to departmental sonographers. We discovered an increased rate of downstream imaging in cases in which residents performed limited scans and did not document visualization of the pelvic organs.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

NSQIP Based Predictors of False Negative and Indeterminate Ultrasounds in Adults With Appendicitis

BACKGROUND

It has been well established that ultrasound (US) is the initial screening tool for children with suspected acute appendicitis. However, computed tomography (CT) has become the standard screening modality for adults presenting with abdominal pain. A recent review of National Surgical Quality Improvement Program (NSQIP) data revealed US is being utilized as a screening modality in adults. We aimed to assess the diagnostic performance of US in evaluating adults with acute appendicitis.

STUDY DESIGN

The American College of Surgeons NSQIP and NSQIP Procedure Targeted Data Files were accessed and examined for all patients in 2016 and 2017 who received an US and underwent an appendectomy. The US results were then correlated to the pathology in order to determine the diagnostic performance. Additionally, we identified predictors for indeterminate and false negative US results.

RESULTS

Our study included 3607 appendectomy patients of which 1135 (30%) had an indeterminate US, 683 (18%) had an US not consistent with appendicitis, and 1789 (49%) had an US consistent with appendicitis. Sensitivity and Specificity were 74.3% and 53.0%, respectively. Positive Predictive Value (PPV) and Negative Predictive Value (NPV) were 95.9% and 12.2%, respectively. On regression analysis, clinically relevant predictors for false negative and indeterminate studies included age, sex, and BMI.

CONCLUSIONS

Ultrasound is an effective initial imaging modality for acute appendicitis in the adult population. Females, age >30 y, and elevated BMI were more likely to have indeterminate or false negative results. These patients may benefit from CT as their initial screening test.

Ultrasound and CT in the Diagnosis of Appendicitis: Accuracy With Consideration of Indeterminate Examinations According to STARD Guidelines

OBJECTIVE. The objective of our study was to determine the accuracy of ultrasound (US) and CT in diagnosing appendicitis at our institution while taking into account the number of indeterminate examinations in accordance with the Standards for Reporting Diagnostic Accuracy (STARD) guidelines. MATERIALS AND METHODS. We retrospectively evaluated 790 patients who underwent US, CT, or both for evaluation of suspected appendicitis between May 1, 2013, and April 30, 2015. Patient characteristics and US and CT examination results were recorded. The reference standard was histopathology or 3 months of medical record follow-up if surgery was not performed; 3 × 2 tables were generated, and sensitivity, specificity, overall test yield, and accuracy were calculated according to STARD guidelines. For surgical cases, time to surgery (one-way ANOVA) was compared among patients who underwent US alone, CT alone, or both US and CT. RESULTS. A total of 473 of 562 US examinations had indeterminate findings (overall test yield, 15.8%); sensitivity and specificity in the 89 diagnostic examinations were 98.5% and 54.2%, respectively. Thirteen of 522 CT examinations were indeterminate (overall test yield, 97.5%); sensitivity and specificity in the remaining 509 CT examinations were 98.9% and 97.2%, respectively. Taking indeterminate studies into account, the accuracy was 13.7% for US and 95.6% for CT. The negative appendectomy rates were 17.7% (11/62) for US and 3.3% (9/276) for CT (p = 0.0002). Time to surgery was longer for patients who underwent US and CT (mean ± SD, 17.7 ± 8.9 hours) than US alone (12.9 ± 6.4 hours; p = 0.002) but was not longer for patients who underwent CT alone (16.3 ± 8.4 hours; p = 0.45). CONCLUSION. At our institution, a large proportion of US examinations are indeterminate for appendicitis. CT is the preferred first-line imaging test for evaluating appendicitis in nonobstetric adult patients.

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

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

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

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

Factors Influencing the Result of Sonographic Diagnosis of Acute Appendicitis in a Large Hospital in the Netherlands

Objective:

Appendicitis is a common surgical emergency, for which sonography is widely used to assess the presence of absence of appendicitis. The objective of this study was to identify factors associated with the diagnostic accuracy of sonography in patients with a suspected case of acute appendicitis.

Methods:

A retrospective review was conducted in all patients who were assessed for acute appendicitis (with sonography) in two emergency rooms of a large hospital. The sonography result was compared with the pathological report in patients who underwent surgery under suspicion of an acute appendicitis.

Results:

A multivariate analysis revealed that operator (radiologist or resident), time of the sonogram, site (hospital), and body mass index were independent variables significantly influencing the sonographic result. Correctly diagnosing suspected appendicitis with sonography is 2.2 times more likely when performed by a radiologist compared to a resident.

Conclusions:

Sonography is widely used in diagnosing appendicitis in the emergency room. In this study, the probability of sonography being correctly diagnosed decreases during on-call hours or when conducted by a resident in patients with suspected appendicitis. Furthermore, increasing body mass index decreases the probability of a sonogram being correct when conducted by a resident compared to a radiologist.

ACR Appropriateness Criteria® Right Lower Quadrant Pain-Suspected Appendicitis

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

A simple algorithm to improve quality while reducing resource utilization in evaluation of suspected appendicitis in children

BACKGROUND

With similar effectiveness of ultrasonography, our institution replaced CT imaging with ultrasound for diagnosing appendicitis in children. An unexpected consequence was the overutilization of ultrasound. Our objective was to establish measures that could help prevent this overuse.

METHODS

A retrospective chart review of 327 consecutive pediatric patients evaluated for appendicitis between October 2014 and September 2015 at our institution was performed. Data on clinical, radiographic, and histopathologic findings were reviewed. Diagnostic accuracy of US and white blood cell (WBC) values was determined. An algorithm was created.

RESULTS

327 (100%) patients received an ultrasound for suspected appendicitis. WBC of 10,000/μl was determined to be the primary discriminant for management and ultrasound utilization. If a WBC ≥10,000/μL had been utilized as criteria for imaging, 49.5% fewer patients would have received an ultrasound.

CONCLUSIONS

Clinical exam, WBC count, and surgery consultation prior to ultrasonography can lessen then need for ultrasound utilization in children with suspected appendicitis.

Secondary imaging for suspected appendicitis after equivocal ultrasound: time to disposition of MRI compared to CT

PURPOSE

The purpose of this study was to compare MRI to CT as a secondary imaging modality for children age 5 years and older with suspected appendicitis after an equivocal abdominal ultrasound in terms of (1) the time to ED disposition decision, (2) surgery consultation rate, and (3) imaging test accuracy.

METHODS

We retrospectively studied children with suspected appendicitis and equivocal ultrasound results who underwent MR or CT as secondary imaging in a pediatric emergency department over two-consecutive 9-month periods. No oral or intravenous contrast was utilized for MRI. No sedation was utilized for any modality. Time of disposition is the time to admission or discharge order.

RESULTS

Twenty-five patients underwent CT and 30 underwent MRI, with no significant difference in the median time from ultrasound to disposition between the CT (5.9 h, IQR 4.5, 8.4) and the MRI (5.9 h, IQR 4.6, 6.9) groups (p = 0.65). Fifteen patients had appendicitis. Of the 40 negative or equivocal studies, surgery was consulted for 79% in the CT and 48% in the MRI group (odds ratio 4.12, 95% CI 1.02-16.67). Diagnostic accuracy was as follows: MRI: sensitivity of 90%, specificity of 97.1%, positive predictive value of 90%, and negative predictive value of 97.1%. Abdominal CT: sensitivity of 88%, specificity of 98.6%, positive predictive value of 95.7%, and negative predictive value of 95.8%.

CONCLUSION

MRI is a feasible alternative to CT for secondary imaging in acute appendicitis for showing comparable ED throughput metrics and diagnostic accuracy, with added benefits of reduced radiation and avoidance of intravenous contrast.

Diagnostic reliability of pediatric appendicitis score, ultrasound and low-dose computed tomography scan in children with suspected acute appendicitis

Background

Diagnosis of appendicitis in children is clinically challenging. Computed tomography (CT) is the gold standard for diagnosis; however, radiation exposure early in life is a concern with this technique. Therefore, in this study, we aimed to evaluate the diagnostic reliability of low-dose CT, pediatric appendicitis score (PAS), and abdominal ultrasound (US) in children with acute appendicitis, to reach a safe diagnosis.

Patients and methods

This retrospective study was conducted on 140 children who were admitted with clinically suspected acute appendicitis (45 with positive appendicitis and 95 children with negative appendicitis). Low-dose CT was performed, and PAS was retrospectively calculated for all subjects. US was initially performed for 38 subjects. All results were compared with the final diagnosis reached by an operative, histopathological analysis and follow-up.

Results

Low-dose CT showed a sensitivity, specificity, and accuracy of 97.8%, 100%, and 99.3%, respectively. At a cutoff value ≥5, PAS showed a sensitivity, specificity, and accuracy of 95%, 84%, and 89%, respectively. Abdominal US examination showed sensitivity, specificity, and accuracy of 55.6%, 85%, and 71%, respectively. Implementing Poortman’s model resulted in higher accuracy (92%) of US. There was a significant difference in accuracy between a low-dose CT and PAS on one side and between Poortman’s model and US examination on the other side. A diagnostic scheme was suggested using PAS as the excluding tool (PAS ≤2 send home and ≥7 send directly to operation) followed by US examination and reserving low-dose CT for inconclusive cases. This scheme would eliminate the use of CT for at least 33.7% and in 7 cases who had initial US examination.

Conclusion

Although CT remains the most accurate and less operator-dependent diagnostic tool for pediatric appendicitis, the radiation hazards could however be minimized using PAS as an excluding tool and US as the primary imaging modality followed by low-dose CT for inconclusive cases only.