CT and US in the diagnosis of appendicitis: an argument for CT

Blood biomarkers to distinguish complicated and uncomplicated appendicitis in pediatric patients

BACKGROUND

/Purpose: Acute appendicitis (AA) stands as the most prevalent cause of acute abdominal pain among children. The potential for morbidity escalates significantly when uncomplicated appendicitis (UA) progresses to complicated appendicitis (CA), which can encompass gangrenous, necrotic, or perforated appendicitis. Consequently, establishing an early and accurate diagnosis of AA, and effectively differentiating CA from UA, becomes paramount. This study explores the diagnostic utility of various blood biomarkers for distinguishing CA from UA in pediatric patients.

METHODS

We conducted a retrospective review of medical records pertaining to pediatric patients who underwent surgery for AA. Patients were categorized as either having UA or CA based on histopathological examination of the appendix. The data collected and analyzed included demographic information, white blood cell (WBC) count, neutrophil proportion, lymphocyte proportion, neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), platelet-to-lymphocyte ratio (PLR), and C-reactive protein (CRP) levels upon admission.

RESULTS

Among the 192 pediatric patients who underwent surgery for AA, 150 were diagnosed with UA, while 42 were diagnosed with CA. The CA group exhibited significantly higher neutrophil proportions, NLRs, PLRs, and CRP levels, alongside lower lymphocyte proportions (all p < 0.01) compared to the UA group. Receiver operating characteristic (ROC) curve analysis disclosed that CRP exhibited the highest specificity, sensitivity, and positive and negative predictive values for predicting CA.

CONCLUSION

CRP emerges as a valuable biomarker for differentiating complicated appendicitis from uncomplicated appendicitis.

The Prognostic Value of Ultrasound Findings in Preoperatively Distinguishing between Uncomplicated and Complicated Types of Pediatric Acute Appendicitis Based on Correlation with Intraoperative and Histopathological Findings

OBJECTIVE

This study compares the preoperative ultrasound findings of all children with a clinical picture of acute appendicitis on the basis of intraoperative and histopathological findings to assess the feasibility of this approach in preoperatively distinguishing between uncomplicated and complicated cases.

METHODS

This retrospective study includes 224 pediatric patients who underwent ultrasound prior to appendectomy at our institution between January 2016 and February 2022. Logistic regression analysis was used to investigate the association between sonographic and intraoperative histopathological findings.

RESULTS

Of the 224 participants, 61.1% were intraoperatively diagnosed with uncomplicated appendicitis (59.8% male). Multivariate logistic regression analysis revealed that patients with a higher appendiceal diameter, presence of appendicolith, and peritonitis were more likely to suffer from complicated appendicitis. Finally, the common anatomical position of the appendix and an appendiceal diameter greater than 6 mm had the highest sensitivity (94.6% and 94.5%, respectively) for predicting complicated appendicitis, with the most specific (99.3%) sonographic finding being the existence of an abscess.

CONCLUSIONS

Preoperative abdominal ultrasound in children with a clinical diagnosis of acute appendicitis can distinguish between uncomplicated and complicated appendicitis in most cases of pediatric appendicitis. A higher appendiceal diameter, the presence of appendicolith, and peritonitis are parameters noted by ultrasound that strongly predict complicated appendicitis.

Diagnostic accuracy of ultrasound in diagnosing acute appendicitis in pregnancy: a systematic review and meta-analysis

BACKGROUND

Lack of timely diagnosis of acute appendicitis (AA) can lead to perforation and peritonitis, which might be associated with complications such as miscarriage, preterm delivery, fetal loss, and even maternal mortality. The aim of the present systematic review and meta-analysis was to evaluate the accuracy of ultrasonography (US) for diagnosing AA in pregnant patients.

METHODS

We performed the present systematic review and meta-analysis based on Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). Using a pre-designed standard datasheet, the two authors summarized the data of each study independently. Pregnant women with diagnosed or suspected AA, who have undergone ultrasonography, as well as using CT scan or surgery as the standard method, were included.

RESULTS

A total of 8 studies consisting of 1593 patients were included. The main analysis showed that the overall sensitivity and specificity were 77.6% and 75.3% for US in diagnosing AA in pregnancy. The sensitivity of US in the first, second, and third trimesters of pregnancy were 69%, 63%, and 51%, respectively. While the corresponding figures for specificity were 85%, 85%, and 65%. There was a significant difference in the diagnostic performance of US between the first two trimesters and the third one. The DORs in these three trimesters were 36, 26, and 1.92, respectively.

CONCLUSIONS

Ultrasound evaluation showed a low diagnostic accuracy for acute appendicitis in pregnant women, especially during the third trimester. These patients should be diagnosed early and accurately to prevent both complications and unnecessary operations. It can be recommended to consider alternative imaging, mostly after negative or uncertain US.

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.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

KEY POINTS

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

Clinical Prediction Score for Ruptured Appendicitis in ED

Background

Ruptured appendicitis has a high morbidity and mortality and requires immediate surgery. The Alvarado Score is used as a tool to predict the risk of acute appendicitis, but there is no such score for predicting rupture. This study aimed to develop the prediction score to determine the likelihood of ruptured appendicitis in an Asian population.

Methods

This study was a diagnostic, retrospective cross-sectional study in the Emergency Medicine Department of Ramathibodi Hospital between March 2016 and March 2018. The inclusion criteria were age >15 years and an available pathology report after appendectomy. Clinical factors included gender, age>60 years, right lower quadrant pain, migratory pain, nausea and/or vomiting, diarrhea, anorexia, fever>37.3°C, rebound tenderness, guarding, white blood cell count, polymorphonuclear white blood cells (PMN) > 75%, and pain duration before presentation. The predictive model and prediction score for ruptured appendicitis were developed by multivariable logistic regression analysis.

Result

During the study period, 480 patients met the inclusion criteria; of these, 77 (16%) had ruptured appendicitis. Five independent factors were predictive of rupture, age>60 years, fever>37.3°C, guarding, PMN>75%, and duration of pain>24 hours to presentation. A score >6 increased the likelihood ratio of ruptured appendicitis by 3.88 times.

Conclusion

Using the Ramathibodi Welawat Ruptured Appendicitis Score (RAMA WeRA Score) developed in this study, a score of >6 was associated with ruptured appendicitis.

Magnetic Resonance Imaging Provides Useful Diagnostic Information Following Equivocal Ultrasound in Children With Suspected Appendicitis

PURPOSE

In Canada, ultrasonography is the primary imaging modality for children with suspected appendicitis, yet equivocal studies are common. Magnetic resonance imaging provides promise as an adjunct imaging strategy. The primary objective of this study was to determine the proportion of children with suspected appendicitis and equivocal ultrasound where magnetic resonance imaging determined a diagnosis.

METHODS

A prospective consecutive cohort of children aged 5-17 years presenting to a tertiary pediatric Emergency Department with suspected appendicitis were enrolled. Participants underwent diagnostic and management strategies according to our local suspected appendicitis pathway, followed by magnetic resonance (Siemens Avanto 1.5 Tesla) imaging. Sub-specialty pediatric radiologists reported all images.

RESULTS

Magnetic resonance imaging was performed in 101 children with suspected appendicitis. The mean age was 11.9 (SD 3.4) years and median Pediatric Appendicitis Score was 6 [IQR 4,8]. Ultrasonography was completed in 98/101 (97.0%). Of 53/98 (54.1%) with equivocal ultrasound, magnetic resonance imaging provided further diagnostic information in 41 (77.4%; 10 positive, 31 negative; 12 remained equivocal). Secondary findings of appendicitis on magnetic resonance imaging in children with equivocal ultrasound included abdominal free fluid (24, 45.3%), peri-appendiceal fluid (12, 22.6%), intraluminal appendiceal fluid (9, 17.0%), fat stranding (8, 15.1%), appendicolith (2, 3.8%), and peri-appendiceal abscess (1, 1.9%). The observed agreement between magnetic resonance imaging results and final diagnosis was 94.9% (kappa = 0.89).

Acute appendicitis and the role of pre-operative imaging: A cohort study

INTRODUCTION

Acute right iliac fossa (RIF) pain is amongst the most common presentation to the surgical team. Acute appendicitis is the most common cause of this pain and often warrants surgical intervention. In many cases intervention results in a negative appendicectomy with unnecessary complications as a result. The aim of this study was to compare the efficacy of pre-operative imaging in the diagnosis of acute appendicitis to reduce the rate of negative appendicectomy and unnecessary operative intervention.

METHODS

A retrospective single centre cohort study was undertaken in a district general hospital (DGH) of all laparoscopic appendicectomies over a six-year period. 1344 cases were included and were examined for the use of pre-operative imaging (and type) or none. The sensitivity, specificity, negative and positive predictive value for each type of imaging were analysed for their accuracy in diagnosis appendicitis based on the final histological analysis.

RESULTS

The negative appendicectomy rate was found to be greatest in those undergoing ultrasonography (48.21%) as their method of pre-operative imaging whilst those who underwent computed tomography (CTAP 20.26%) had a lower rate equivalent to that of clinical diagnosis alone (20.73%).

CONCLUSION

USS is less sensitive than CT in diagnosing acute appendicitis. There is no statistically significant difference in negative appendicectomy rate between clinical diagnosis and CT diagnosis. Pre-operative imaging has a role in the diagnosis of appendicitis but needs to be utilised appropriately to reduce the strain on the surgical department and prevent the potential of a negative appendicectomy.

Synchronous Acute Acalculous Cholecystitis and Appendicitis Due to Salmonella Group D: A Rare Case Report From China and Review of the Literature

Non-typhoidal Salmonella (NTS) disease is not common as typhoid fever but has become a global public health problem in recent decades. Acute acalculous cholecystitis (AAC) and appendicitis are rare complications of NTS infection, which are usually difficult to be diagnosed with atypical signs. Pathogenesis of NTS-induced AAC and NTS-induced appendicitis is still unclear. Ultrasound is the first choice for diagnosis of these two rare complications, computed tomography can assist in and next-generation sequencing (NGS), as a new technology in clinical medicine, also facilitates diagnosis. We described a case of simultaneous AAC and appendicitis due to NTS in an elderly male and further confirmed the diagnosis using NGS. As far as we know, this is the first Asian case of two complications occurring at the same time. Our aim is to alert physicians to pay attention to this rare condition.

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.

The importance of visualization of appendix on abdominal ultrasound for the diagnosis of appendicitis in children: A quality assessment review

BACKGROUND

Ultrasound has the first line investigation role in the diagnosis of acute appendicitis in children. The purpose of this study was to perform a quality assessment review on the visualization rate of appendix on ultrasound in children in the community hospital setting.

METHODS

A retrospective chart review of the abdominal ultrasound findings for the visualization of the appendix was performed on paediatric patients ranging from 5 to 18 years. Data were collected from the two community hospitals of Toronto by using hospital electronic medical record for the ultrasound findings in patients presented with abdominal pain.

RESULTS

Data from two community hospitals indicated visualization rate of the appendix as 11.0% and 23.2% for site 1 and site 2 respectively. In cases where the ultrasound was repeated the visualization rate remains the same. A two-proportion z-test was performed to find whether the visualization of appendix increases the likelihood of diagnosing appendicitis. The results revealed that the visualization of an appendix (P=0.52), significantly improved the diagnosis of appendicitis (z=34, P<0.001).

CONCLUSION

Visualization of an appendix on ultrasound increases the likelihood of correctly diagnosing appendicitis. In our study, we found low visualization rate of appendix on ultrasound that could be the result of many factors that contribute towards the low visualization rate of an appendix on ultrasound. Hence, the challenges in identifying appendix should be minimized to improve the visualization and diagnosis of appendicitis on ultrasound.

AppendiXNet: Deep Learning for Diagnosis of Appendicitis from A Small Dataset of CT Exams Using Video Pretraining

The development of deep learning algorithms for complex tasks in digital medicine has relied on the availability of large labeled training datasets, usually containing hundreds of thousands of examples. The purpose of this study was to develop a 3D deep learning model, AppendiXNet, to detect appendicitis, one of the most common life-threatening abdominal emergencies, using a small training dataset of less than 500 training CT exams. We explored whether pretraining the model on a large collection of natural videos would improve the performance of the model over training the model from scratch. AppendiXNet was pretrained on a large collection of YouTube videos called Kinetics, consisting of approximately 500,000 video clips and annotated for one of 600 human action classes, and then fine-tuned on a small dataset of 438 CT scans annotated for appendicitis. We found that pretraining the 3D model on natural videos significantly improved the performance of the model from an AUC of 0.724 (95% CI 0.625, 0.823) to 0.810 (95% CI 0.725, 0.895). The application of deep learning to detect abnormalities on CT examinations using video pretraining could generalize effectively to other challenging cross-sectional medical imaging tasks when training data is limited.

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.

Accuracy of surgeon prediction of appendicitis severity in pediatric patients

PURPOSE

Clinical prediction of disease severity is important as one considers nonoperative management of simple appendicitis. This study assesses the accuracy of surgeons' prediction of appendicitis severity.

METHODS

From February to August 2016, pediatric surgeons at a single institution were asked to predict whether patients had simple or complex appendicitis preoperatively based on clinical data, imaging, and general assessment. Receiver operating characteristic curves were generated to determine area under the curve (AUC) and optimal cutoff points of clinical findings for diagnosing simple appendicitis. Outcomes included sensitivity and specificity of variables to identify simple appendicitis. Predictions were compared to operative findings using χ². A p-value<0.05 was considered statistically significant.

RESULTS

Of 125 cases (median age 9 years [IQR 7-13], 58% male), simple appendicitis was predicted in 77 (62%) and complex appendicitis in 48 (38%). Predictions were accurate in 59 (77%) simple cases and 45 (94%) complex cases. Although surgeon prediction was more accurate than individual imaging or clinical findings and was highly sensitive (95%) for diagnosing simple appendicitis, specificity was only 71%. Lower WBC (<15.5 × 10³/μL, AUC 0.61, p = 0.05), afebrile (<100.4 °F, AUC 0.86, p < 0.01), and shorter symptom duration (≤ 1.5 days, AUC 0.71, p < 0.001) were associated with simple appendicitis. Of 18 complex cases (14%) inaccurately predicted as simple, 17 (94%) lacked diffuse tenderness, 15 (83%) were well-appearing, 11 (61%) had ultrasound findings of simple appendicitis, 11 (61%) had ≤2 days of symptoms, and 8 (44%) were afebrile (<100.4 °F).

CONCLUSION

While surgeon prediction of simple appendicitis is more accurate than ultrasound or clinical data alone, diagnostic accuracy is still limited.

TYPE OF STUDY

Prospective survey.

LEVEL OF EVIDENCE

II.

Can Surgeons Identify Appendicitis Macroscopically? Results From a Multicentre Prospective Study

PURPOSE

The primary outcome was to investigate the accuracy of intraoperative macroscopic diagnosis by the operating surgeon with the results of the subsequent histopathologic examination. The secondary outcome was to identify the predictors of discrepancies between these 2 groups.

MATERIALS AND METHODS

A multicentre, prospective, observational study was conducted over a period of 2 months with a 30-day follow-up period. Patients who underwent surgery with the intention of appendicectomy were recruited in the study.

RESULTS

A total of 1169 patients were recruited. False negatives (FNs) were defined as a normal macroscopic diagnosis but histopathologically appendicitis, whereas false positive otherwise. Overall, FN rates were 22.4%, whereas false positive rates were 8.2%. The seniority of the operating surgeons did not affect the ability to accurately diagnose appendicitis macroscopically (P=0.069). However, consultant surgeons had the lowest FN rate of 15.6%. Females and preoperative ultrasound scan increased odds of FN, whereas preoperative computed tomography decreased the odds of FN appendicectomy.

CONCLUSION

Macroscopic identification intraoperatively is inaccurate with a FN rate of 22%.

A new clinical score to identify children at low risk for appendicitis

BACKGROUND

Besides clinical signs and imaging, in recent years, biomarkers have proven to be a viable diagnostic resource for acute appendicitis (AA).

OBJECTIVE

The objective of this study was to develop a clinical score including clinical signs and a combination of biomarkers to identify children with abdominal pain at low risk of AA.

DESIGN/METHODS

We prospectively included children 2 to 14 years of age with abdominal pain suggestive of AA who presented to the emergency department between July 2016 and September 2017. A new score, the Pediatric Appendicitis Laboratory Score (PALabS) including clinical signs, leucocyte (WBC) and neutrophil (ANC) counts and plasma C-reactive protein (CRP) and calprotectin (CP) levels was developed and validated through secondary analyses of two distinct cohorts The validation sample included visits to a single pediatric emergency department from 2012 to 2013 and 2016 to 2017.

RESULTS

The derivation sample included 278 children, 35.9% of whom had AA and the validation sample included 255 children, 49% of whom had AA. Using logistic regression, we created a 6-part score that consisted of nausea (3 points), history of focal right lower quadrant pain (4 points), ANC of ≥7500/μL (7 points), WBC of ≥10,000/μL (4 points), CRP ≥ 10.0 mg/L (2 points) and CP ≥ 0.50 ≥ ng/mL (3 points). This score exhibited a high discriminatory power (area under the curve: 0.88; 95% confidence interval: 0.84 to 0.92) and outperformed the PAS and Kharbanda scores (area under the curve: 0.76; 95% confidence interval: 0.71 to 0.82 and 0.82; 95% confidence interval: 0.77 to 0.87, respectively). A PALabS ≤6 had a sensitivity of 99.2% (95% confidence interval [CI]: 95.6-99.9), negative predictive value of 97.6% (95% CI: 87.7-99.6), and negative likelihood ratio of 0.03 (95% CI: 0.00-0.18) in the validation set.

CONCLUSION

In our validation cohort of patients with acute abdominal pain, the new score can accurately predict which children are at low risk of appendicitis and could be safely managed with close observation.

Diagnostic performance and useful findings of ultrasound re-evaluation for patients with equivocal CT features of acute appendicitis

OBJECTIVE

To evaluate the diagnostic performance of ultrasound and to determine which ultrasound findings are useful to differentiate appendicitis from non-appendicitis in patients who underwent ultrasound re-evaluation owing to equivocal CT features of acute appendicitis.

METHODS

62 patients who underwent CT examinations for suspected appendicitis followed by ultrasound re-evaluation owing to equivocal CT findings were included. Equivocal CT findings were considered based on the presence of only one or two findings among the CT criteria, and ultrasound re-evaluation was done based on a predefined structured report form. The diagnostic performance of ultrasound and independent variables to discriminate appendicitis from non-appendicitis were assessed.

RESULTS

There were 27 patients in the appendicitis group. The overall diagnostic performance of ultrasound re-evaluation was sensitivity of 96.3%, specificity of 91.2% and accuracy of 91.9%. In terms of the performance of individual ultrasound findings, probe-induced tenderness showed the highest accuracy (86.7%) with sensitivity of 74% and specificity of 97%, followed by non-compressibility (accuracy 71.7%, sensitivity 85.2% and specificity 60.6%). The independent ultrasound findings for discriminating appendicitis were non-compressibility (p = 0.002) and increased flow on the appendiceal wall (p = 0.001).

CONCLUSION

Ultrasound re-evaluation can be used to improve diagnostic accuracy in cases with equivocal CT features for diagnosing appendicitis. The presence of non-compressibility and increased vascular flow on the appendix wall are useful ultrasound findings to discriminate appendicitis from non-appendicitis. Advances in knowledge: Ultrasound re-evaluation is useful to discriminate appendicitis from non-appendicitis when CT features are inconclusive.

Effectiveness of a Staged US and Unenhanced MR Imaging Algorithm in the Diagnosis of Pediatric Appendicitis

Purpose To establish, in a large cohort, the diagnostic performance of a staged algorithm involving ultrasonography (US) followed by conditional unenhanced magnetic resonance (MR) imaging for the imaging work-up of pediatric appendicitis. Materials and Methods A staged imaging algorithm in which US and unenhanced MR imaging were performed in pediatric patients suspected of having appendicitis was implemented at the authors' institution on January 1, 2011, with US as the initial modality followed by unenhanced MR imaging when US findings were equivocal. A search of the radiology database revealed 2180 pediatric patients who had undergone imaging for suspected appendicitis from January 1, 2011, through December 31, 2012. Of the 2180 patients, 1982 (90.9%) were evaluated according to the algorithm. The authors reviewed the electronic medical records and imaging reports for all patients. Imaging reports were reviewed and classified as positive, negative, or equivocal for appendicitis and correlated with surgical and pathology reports. Results The frequency of appendicitis was 20.5% (407 of 1982 patients). US alone was performed in 1905 of the 1982 patients (96.1%), yielding a sensitivity of 98.7% (386 of 391 patients) and specificity of 97.1% (1470 of 1514 patients) for appendicitis. Seventy-seven patients underwent unenhanced MR imaging after equivocal US findings, yielding an overall algorithm sensitivity of 98.2% (400 of 407 patients) and specificity of 97.1% (1530 of 1575 patients). Seven of the 1982 patients (0.4%) had false-negative results with the staged algorithm. The negative predictive value of the staged algorithm was 99.5% (1530 of 1537 patients). Conclusion A staged algorithm of US and unenhanced MR imaging for pediatric appendicitis appears to be effective. The results of this study demonstrate that this staged algorithm is 98.2% sensitive and 97.1% specific for the diagnosis of appendicitis in pediatric patients. ^© RSNA, 2017.

Anatomic Reasons for Failure to Visualize the Appendix With Graded Compression Sonography: Insights From Contemporaneous CT

OBJECTIVE

The purpose of this study is to identify the anatomic locations of appendixes on CT when graded compression sonography fails to visualize the appendix.

MATERIALS AND METHODS

The study included 197 patients with suspected appendicitis whose appendixes were not visualized on graded compression sonography performed with typically used transducers of at least 10 MHz, who underwent CT within 48 hours following graded compression sonography, and who had available either pathologic examination following surgery or 6-week follow-up if surgery was not performed. Appendixes were retrospectively localized using four transverse quadrants (including the posteromedial quadrant) centered on the ileocecal valve and projected vertically, the craniocaudal level relative to the iliac crests, and the depth of the appendix as measured from the surface of the skin. Data were assessed using the Fisher exact test, t test, multinomial test, binomial distribution, ANOVA, and linear regression.

RESULTS

Appendixes were most frequently located in the posteromedial quadrant (123 of 197 patients [62.4%]; 95% CI, 55.3-69.2%) at a statistically significantly greater frequency than that expected by chance (p < 0.00001). Appendixes were located above the iliac crests in 19.8% of patients (39/197; 95% CI, 14.5-26.1%) and at depths exceeding the penetration of typical transducers of at least 10 MHz in 19.3% of patients (38/197; 95% CI, 14.0-25.5%). All appendixes (95% CI, 98.1-100.0%) were located within the range of 6-MHz transducers.

CONCLUSION

Appendixes that are not visualized on graded compression sonography are most frequently located in the posteromedial quadrant and are often located above the iliac crests or at depths too great for visualization with typically used transducers of at least 10 MHz. Accordingly, when the appendix is not visualized on graded compression sonography, targeted scanning of the posteromedial quadrant and the region above the iliac crests, and scanning with 6-MHz transducers, may enable visualization of the appendix and are recommended additions to scanning protocols.

Creating diagnostic criteria for perforated appendicitis using cross-sectional imaging

INTRODUCTION

Preoperative determination of perforated versus acute appendicitis can be difficult. We compared CT and MRI performance in diagnosing perforated appendicitis, and created diagnostic criteria.

METHODS

We retrospectively reviewed all pediatric patients who underwent appendectomy within one day of CT or MRI between 1/1/2013 and 1/16/2016. True diagnosis was determined by pathology report. Findings on CT/MRI were grouped into "hard" findings (abscess, pneumoperitoneum, extruded fecalith, appendiceal wall with visible hole) and "soft" findings (extensive/diffuse inflammation/free fluid, phlegmon). Correlation of white blood cell count (WBC), temperature, peritoneal signs, and symptom duration >72 h with perforation was assessed using logistic regression. Significant correlates were incorporated in clinical criteria.

RESULTS

135 patients underwent appendectomy after CT/MRI. Fifty patients underwent MRI and 85 CT. Using hard and/or soft findings, MRI was 86.7% sensitive and 74.3% specific, compared to 68.4% (p = 0.19) and 92.4% (p = 0.025) for CT. WBC > 15, temperature >38.0 °C, and peritoneal signs predicted perforation. Diagnostic accuracy of MRI was highest using imaging findings alone. Accuracy of CT was improved by mandating at least one of the previous three clinical correlates, resulting in 68.4% sensitivity and 93.9% specificity.

CONCLUSIONS

MRI trended toward more sensitive and CT was more specific for complicated appendicitis. CT specificity is improved by our algorithm.

Early appendectomy reduces costs in children with perforated appendicitis

BACKGROUND

Perforated appendicitis can be managed with early appendectomy, or nonoperative management followed by interval appendectomy. We aimed to identify the strategy with the lowest health care utilization and cost.

METHODS

We retrospectively reviewed the medical records of all children ≤18 years old with perforated appendicitis admitted to a single institution between January 2009 and March 2016. After excluding immunosuppressed patients and transfers from outside hospitals, we grouped the remaining patients by early or interval appendectomy. Cost accounting data were obtained from our institutional database. The primary outcome was total hospital cost over 2 y from initial admission for appendicitis. Other outcomes analyzed included initial admission costs, number of admissions, emergency room and clinic visits, percutaneous procedures, cross-sectional and overall imaging studies, and length of stay.

RESULTS

A total of 203 children with perforated appendicitis were identified. After exclusion of immunosuppressed patients and outside hospital transfers, 94 patients were included in the study. Thirty-nine underwent early appendectomy and 55 initial nonoperative management; of these, 54 underwent elective interval appendectomy. Five of 55 patients (9%) failed initial nonoperative management and required earlier-than-planned appendectomy. Total cost over 2 y was significantly lower with early appendectomy than initial nonoperative management ($19,300 ± 14,300 versus $26,000 ± 17,500; P = 0.05). Early appendectomy resulted in fewer hospital admissions, clinic visits, invasive procedures, and imaging studies.

CONCLUSIONS

Early appendectomy results in lower hospital costs and less health care utilization compared with initial nonoperative management with elective interval appendectomy. A prospective study will shed more light on this question and can assess the role of nonoperative management without interval appendectomy in children with perforated appendicitis.

Magnetic Resonance Imaging Versus Ultrasound as the Initial Imaging Modality for Pediatric and Young Adult Patients With Suspected Appendicitis

BACKGROUND

While ultrasound (US), given its lack of ionizing radiation, is currently the recommended initial imaging study of choice for the diagnosis of appendicitis in pediatric and young adult patients, it does have significant shortcomings. US is time-intensive and operator dependent and results in frequent inconclusive studies, thus necessitating further imaging and admission for observation or repeat clinical visits. A rapid focused magnetic resonance imaging (MRI) for appendicitis has been shown to have definitive sensitivity and specificity, similar to computed tomography but without radiation and offers a potential alternative to US.

OBJECTIVE

In this single-center prospective cohort study, we sought to determine the difference in total length of stay and charges between rapid MRI and US as the initial imaging modality in pediatric and young adult patients presenting to the emergency department (ED) with suspected appendicitis. We hypothesized that rapid MRI would be more efficient and cost-effective than US as the initial imaging modality in the ED diagnosis of appendicitis.

METHODS

A prospective randomized cohort study of consecutive patients was conducted in patients 2 to 30 years of age in an academic ED with access to both rapid MRI and US imaging modalities 24/7. Prior to the start of the study, the days of the week were randomized to either rapid MRI or US as the initial imaging modality. Physicians evaluated patients with suspected appendicitis per their usual manner. If the physician decided to obtain radiologic imaging, the predetermined imaging modality for the day of the week was used. All decisions regarding other diagnostic testing and/or further imaging were left to the physician's discretion. Time intervals (minutes) between triage, order placement, start of imaging, end of imaging, image result, and disposition (discharge vs. admission), as well as total charges (diagnostic testing, imaging, and repeat ED visits) were recorded.

RESULTS

Over a 100-day period, 82 patients were imaged to evaluate for appendicitis; 45 of 82 (55%) of patients were in the US-first group, and 37 of 82 (45%) patients were in the rapid MRI-first group. There were no differences in patient demographics or clinical characteristics between the groups and no cases of missed appendicitis in either group. Eleven of 45 (24%) of US-first patients had inconclusive studies, resulting in follow-up rapid MRI and five return ED visits contrasted with no inconclusive studies or return visits (p < 0.05) in the rapid MRI group. The rapid MRI compared to US group was associated with longer ED length of stay (mean difference = 100 minutes; 95% confidence interval [CI] = 35-169 minutes) and increased ED charges (mean difference = $4,887; 95% CI = $1,821-$8,513).

CONCLUSIONS

In the diagnosis of appendicitis, US-first imaging is more time-efficient and less costly than rapid MRI despite inconclusive studies after US imaging. Unless the process of obtaining a rapid MRI becomes more efficient and less expensive, US should be the first-line imaging modality for appendicitis in patients 2 to 30 years of age.

How to diagnose an acutely inflamed appendix; a systematic review of the latest evidence

Acute appendicitis is the most common condition that presents with an acute abdomen needing emergency surgery. Despite this common presentation, correctly diagnosing appendicitis remains a challenge as clinical signs or positive blood results can be absent in 55% of the patients. The reported proportion of missed diagnoses of appendicitis ranges between 20% and 40%. A delay or mis-diagnosis of appendicitis can result in severe complications such as perforation, abscess formation, sepsis, and intra-abdominal adhesions. Literature has shown that patients who had a negative appendectomy suffer post-op complications and infections secondary to hospital stays; there have even been reported cases of fatality. It is therefore crucial that timely and accurate diagnosis of appendicitis is achieved to avoid complications of both non-operating as well as unnecessary surgical intervention. The aim of this review is to systematically report and analyse the latest evidence on the different approaches used in diagnosing appendicitis. We include discussions of clinical scoring systems, laboratory tests, latest innovative bio-markers and radiological imaging.

Acute appendicitis in young children less than 5 years: review article

Despite wide spread availability of sophisticated diagnostic imaging, acute appendicitis in pre-school children remains a diagnostic challenge. Most of these children present late, often with complications e.g. appendicular perforation, abscess formation and peritonitis and as result hospital stay is prolonged and is associated with increased morbidity and mortality.The purpose of this article is to review peculiar features of acute appendicitis in preschool children.

Benchmarking the value of ultrasound for acute appendicitis in children

BACKGROUND

This study appraises the diagnostic quality of ultrasound for acute appendicitis in children and consequently challenges the perception of inferior accuracy and suitability compared to computed tomography (CT).

METHODS

Radiologist reports for consecutive "query appendicitis" ultrasound studies were retrieved from a hospital database for the study period 2009-2014. Children who subsequently underwent appendicectomy were identified. Corresponding operative and histopathology findings were evaluated. Diagnostic accuracy of ultrasound was determined by analyzing overall accuracy, sensitivity, specificity, predictivity, and likelihood ratios.

RESULTS

A total of 3799 ultrasound examinations were evaluated. Mean age was 11.5±3.8years. The proportion of patients investigated with preoperative ultrasound was 59.9% (1103/1840). Appendix visualization rate was 91.7%. Overall diagnostic accuracy was 95.5%. Sensitivity and specificity values were 97.1% (95.9-98.1; 95% CI) and 94.8% (93.9-95.6; 95% CI), respectively. Separate analysis of only ultrasound positive and negative examinations (i.e., excluding nondiagnostic examinations) confirmed sensitivity and specificity values of 98.8% and 98.3%.

CONCLUSION

In this largest reported single institution series of ultrasound examinations for appendicitis, we report benchmark standard quality of diagnostic accuracy and visualization rates. Given the radiation and cost implications of CT, there is a strong argument to recommend ultrasound as the primary imaging modality. Diagnostic Study-Level II.

Unexpected Findings During Evaluation of Acute Pelvic Pain With Transvaginal Sonography

Transvaginal sonography is the first-line imaging modality used to evaluate acute female pelvic pain in the emergency setting because of its accessibility, lack of ionizing radiation, and excellent ability to identify reproductive tract disorders. Although the intent of transvaginal sonography is to evaluate the reproductive organs, imaging of adjacent pelvic structures is an important part of every transvaginal sonographic examination. Gastrointestinal, urologic, and vascular disorders incidentally scanned on transvaginal sonography may explain the pain for which the examination is being performed. In such cases, transvaginal sonography may play an important role in the diagnostic process if the clinician is aware of the transvaginal sonographic appearance of these entities.

An Extremely Rare Coexistence: Acute Appendicitis and Multiple Intussusceptions in an Adult

Background

Adult intussusception is a rare phenomenon, acute appendicitis accompanying multiple transient intussusceptions are much more uncommon. Satisfaction and quiting imaging studies after finding an intussusception on ultrasound, may lead diagnostic errors. Radiologists should raise their awareness of imaging findings in intussusception and keep in their mind coexistent troubles in the belly. This unique case presents unusual imaging findings of a rare dual abdominal emergency condition, particularly highlighting the value of abdominal computed tomography.

Case Report

32-year-old female was admitted to Emergency Department with complaints of epigastric abdominal pain and vomiting. US identified ‘target’ appereance on left paramedian location at umbilical level. Contrast enhanced abdominal CT not only confirmed the enteric intussusception that was demonstrated on previos US, but also showed additional concomitant intussusceptions and inflamed appendix.

Conclusions

Adult intussusception is a rare phenomenon, multiple transient intussusceptions are even more uncommon. This unique report adds, precious clinical and imaging findings of acute appendicitis coexisting with multiple spontaneously resolving intussusceptions, to the literature. Physicians should be alerted for accompanying multiple abdominal pathologies and use justification essentials to make their decisions about the selection of the appropriate imaging modality.

Application of scoring systems with point-of-care ultrasonography for bedside diagnosis of appendicitis

BACKGROUND

Appendicitis is a common disease requiring surgery. Bedside ultrasound (BUS) is a core technique for emergency medicine (EM). The Alvarado score is a well-studied diagnostic tool for appendicitis. This study aimed to investigate the relationship between patients' symptoms, Alvarado score and ultrasound (US) findings, as performed by emergency physicians (EPs) and radiologists, of patients with suspected appendicitis.

METHODS

Three EM specialists underwent the BUS course and core course for appendicitis assessment. Patients suspected of having appendicitis were selected and their Alvarado and modified (m) Alvarado scores calculated. The specialists performed the BUS. Then, patients were given a formal US and surgery consultation if necessary. Preliminary diagnoses, admission or discharge from the emergency department (ED) and final diagnosis were documented. The patients were also followed up after discharge from the hospital.

RESULTS

The determined cut-off value was 2 for Alvarado and 3 for mAlvarado scores. The sensitivities of the two scores were 100%. Each score was used to rule out appendicitis. The results of EP-performed BUS were as follows: accuracy 70%, sensitivity 0.733, specificity 0.673, + LR 2.24, and - LR 0.40 (95%CI). Radiologists were better than EPs at diagnosing appendicitis and radiologists and EPs were equally strong at ruling out appendicitis by US. When US was combined with Alvarado and mAlvarado scores, EP US+Alvarado/mAlvarado scores <3 and radiology US+Alvarado/mAlvarado scores <4 perfectly ruled out appendicitis.

CONCLUSION

BUS performed by EPs is moderately useful in detecting appendicitis. Combined with scoring systems, BUS may be a perfect tool for ruling out decisions in EDs.

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.

An implemented MRI program to eliminate radiation from the evaluation of pediatric appendicitis

BACKGROUND

Recent efforts have been directed at reducing ionizing radiation delivered by CT scans to children in the evaluation of appendicitis. MRI has emerged as an alternative diagnostic modality. The clinical outcomes associated with MRI in this setting are not well-described.

METHODS

Review of a 30-month institutional experience with MRI as the primary diagnostic evaluation for suspected appendicitis (n=510). No intravenous contrast, oral contrast, or sedation was administered. Radiologic and clinical outcomes were abstracted.

RESULTS

MRI diagnostic characteristics were: sensitivity 96.8% (95% CI: 92.1%-99.1%), specificity 97.4% (95% CI: 95.3-98.7), positive predictive value 92.4% (95% CI: 86.5-96.3), and negative predictive value 98.9% (95% CI: 97.3%-99.7%). Radiologic time parameters included: median time from request to scan, 71 minutes (IQR: 51-102), imaging duration, 11 minutes (IQR: 8-17), and request to interpretation, 2.0 hours (IQR: 1.6-2.6). Clinical time parameters included: median time from initial assessment to admit order, 4.1 hours (IQR: 3.1-5.1), assessment to antibiotic administration 4.7 hours (IQR: 3.9-6.7), and assessment to operating room 9.1 hours (IQR: 5.8-12.7). Median length of stay was 1.2 days (range: 0.2-19.5).

CONCLUSION

Given the diagnostic accuracy and favorable clinical outcomes, without the potential risks of ionizing radiation, MRI may supplant the role of CT scans in pediatric appendicitis imaging.

The challenging ultrasound diagnosis of perforated appendicitis in children: constellations of sonographic findings improve specificity

BACKGROUND

Rapid and accurate diagnosis of appendicitis, particularly with respect to the presence or absence of perforation, is essential in guiding appropriate management. Although many studies have explored sonographic findings associated with acute appendicitis, few investigations discuss specific signs that can reliably differentiate perforated appendicitis from acute appendicitis prior to abscess formation.

OBJECTIVE

The purpose of our study was to identify sonographic findings that improve the specificity of US in the diagnosis of perforated appendicitis. Our assessment of hepatic periportal echogenicity, detailed analysis of intraperitoneal fluid, and formulation of select constellations of sonographic findings expands upon the literature addressing this important diagnostic challenge.

MATERIALS AND METHODS

We retrospectively reviewed 116 abdominal US examinations for evaluation of abdominal pain in children ages 2 to 18 years from January 2008 to September 2011 at a university hospital pediatric radiology department. The study group consisted of surgical and pathology proven acute appendicitis (n = 51) and perforated appendicitis (n = 22) US exams. US exams without a sonographic diagnosis of appendicitis (n = 43) confirmed by follow-up verbal communication were included in the study population as the control group. After de-identification, the US exams were independently reviewed on a PACS workstation by four pediatric radiologists blinded to diagnosis and all clinical information. We recorded the presence of normal or abnormal appendix, appendicolith, appendiceal wall vascularity, thick-walled bowel, dilated bowel, right lower quadrant (RLQ) echogenic fat, increased hepatic periportal echogenicity, bladder debris and abscess or loculated fluid. We also recorded the characteristics of intraperitoneal fluid, indicating the relative quantity (number of abdominal regions) and quality of the fluid (simple fluid or complex fluid). We used logistic regression for correlated data to evaluate the association of diagnosis with the presence versus absence of each US finding. We conducted multivariable analysis to identify constellations of sonographic findings that were predictive of perforated appendicitis.

RESULTS

The individual US findings of abscess/loculated fluid, appendicolith, dilated bowel and increased hepatic periportal echogenicity were significantly associated with perforated appendicitis when compared with acute appendicitis (P < 0.01). The sonographic observation of increased hepatic periportal echogenicity demonstrated a statistically significant association with perforated appendicitis compared with acute appendicitis (P < 0.01). The presence of complex fluid yielded a specificity of 87.7% for perforated appendicitis compared with the acute appendicitis group. The US findings of ≥2 regions or ≥3 regions with fluid had specificity of 87.3% and 99.0%, respectively, for perforated appendicitis compared with the acute appendicitis group. Select combinations of sonographic findings yielded high specificity in the diagnosis of perforated appendicitis compared with acute appendicitis. These constellations yielded higher specificity than that of each individual finding in isolation. The constellation of dilated bowel, RLQ echogenic fat, and complex fluid had the highest specificity (99.5%) for perforated appendicitis (P < 0.01).

CONCLUSION

Our study demonstrates that identification of select constellations of findings using abdominal sonography, in addition to focused US examination of the right lower quadrant, can improve sonographic diagnosis of perforated appendicitis in the pediatric population.

Appendicitis in children less than five years old: A challenge for the general practitioner

Acute appendicitis is one of the most common indications for abdominal surgery in pediatrics with peak incidence in the second decade of life. Acute appendicitis in the first years of life is an uncommon event. The clinical presentation is often varied and the diagnosis may be overshadowed by other medical conditions. Gastroenteritis is the most common misdiagnosis, with a history of diarrhea present in 33% to 41% of patients. Pain is the most common presenting symptom in children less than 5 years old, followed by vomiting, fever, anorexia and diarrhea. The most common physical sign is focal tenderness (61% of the patients) followed by guarding (55%), diffuse tenderness (39%), rebound (32%), and mass (6%). Neonatal appendicitis is a very rare disease with high mortality; presenting symptoms are nonspecific with abdominal distension representing the main clinical presentation. The younger the patient, the earlier perforation occurs: 70% of patients less than 3 years develop a perforation within 48 h of onset of symptoms. A timely diagnosis reduces the risk of complications. We highlight the epidemiology, pathophysiology, clinical signs and laboratory clues of appendicitis in young children and suggest an algorithm for early diagnosis.

Sonographic distinction between acute suppurative appendicitis and viral appendiceal lymphoid hyperplasia ("pink appendix") with pathological correlation

The viral etiology of mesenteric lymphadenitis may also affect the lymphoid tissue of the appendix in children giving rise to symptomatic appendiceal lymphoid hyperplasia, the so-called "pink appendix." The present study used ultrasound (US) to determine if certain sonographic features correlated with appendiceal pathological findings. Our results indicate that a fluid-filled appendix always correlates with a suppurative or mixed pathological appearance that likely merits surgery. A lymphoid predominant pathological appearance occurred only in cases where appendiceal wall thickening alone was seen on US. This pilot project therefore shows that US has the potential to stratify acute appendix patients into different treatment regimens, given that lymphoid hyperplasia could be treated conservatively. Further studies correlating other clinicoradiological parameters with this sonographic appearance are warranted.

Journal Club: the Alvarado score as a method for reducing the number of CT studies when appendiceal ultrasound fails to visualize the appendix in adults

OBJECTIVE. The purpose of this article is to evaluate the hypothesis that Alvarado scores of 3 or lower identify adult patients who are unlikely to benefit from CT after appendiceal ultrasound fails to show the appendix and is otherwise normal. MATERIALS AND METHODS. We identified 119 consecutive adults for whom the appendix was not seen on otherwise normal appendiceal sonography performed as the first imaging study for suspected appendicitis, who subsequently underwent CT within 48 hours, and whose data permitted retrospective calculation of admission Alvarado scores. Specific benefits of CT were defined as diagnoses of appendicitis or significant alternative findings, and specific benefits were compared between patients with Alvarado scores of 3 or less and 4 or higher. Significant alternative findings on CT were findings other than appendicitis that were treated with medical or surgical therapy during the admission or that were to be addressed during follow-up care. Diagnostic reference standards were discharge diagnoses, pathologic examinations, and clinical follow-up. RESULTS. No patients (0.0%, 0/49) with Alvarado scores 3 or lower had appendicitis, compared with 17.1% (12/70) of patients with Alvarado scores 4 or higher (p = 0.001), and CT showed neither appendicitis nor significant alternative findings in 85.7% (42/49) versus 58.6% (41/70) of these patients, respectively (p = 0.002). The rates of perforated appendicitis, as well as significant alternative CT findings, did not differ significantly. CONCLUSION. Adults with Alvarado scores 3 or lower who have nonvisualized appendixes and otherwise normal appendiceal sonography are at very low risk for appendicitis or significant alternative findings and therefore are not likely to benefit from CT.

Three-step sequential positioning algorithm during sonographic evaluation for appendicitis increases appendiceal visualization rate and reduces CT use

OBJECTIVE

The purpose of this article is to examine the rates of appendiceal visualization by sonography, imaging-based diagnoses of appendicitis, and CT use after appendiceal sonography, before and after the introduction of a sonographic algorithm involving sequential changes in patient positioning.

MATERIALS AND METHODS

We used a search engine to retrospectively identify patients who underwent graded-compression sonography for suspected appendicitis during 6-month periods before (period 1; 419 patients) and after (period 2; 486 patients) implementation of a new three-step positional sonographic algorithm. The new algorithm included initial conventional supine scanning and, as long as the appendix remained nonvisualized, left posterior oblique scanning and then "second-look" supine scanning. Abdominal CT within 7 days after sonography was recorded.

RESULTS

Between periods 1 and 2, appendiceal visualization on sonography increased from 31.0% to 52.5% (p < 0.001), postsonography CT use decreased from 31.3% to 17.7% (p < 0.001), and the proportion of imaging-based diagnoses of appendicitis made by sonography increased from 63.8% to 85.7% (p = 0.002). The incidence of appendicitis diagnosed by imaging (either sonography or CT) remained similar at 16.5% and 17.3%, respectively (p = 0.790). Sensitivity and overall accuracy were 57.8% (95% CI, 44.8-70.1%) and 93.0% (95% CI, 90.1-95.3%), respectively, in period 1 and 76.5% (95% CI, 65.8-85.2%) and 95.4% (95% CI, 93.1-97.1%), respectively, in period 2. Similar findings were observed for adults and children.

CONCLUSION

Implementation of an ultrasound algorithm with sequential positioning significantly improved the appendiceal visualization rate and the proportion of imaging-based diagnoses of appendicitis made by ultrasound, enabling a concomitant decrease in abdominal CT use in both children and adults.

Computed tomography: revolutionizing the practice of medicine for 40 years

Computed tomography (CT) has had a profound effect on the practice of medicine. Both the spectrum of clinical applications and the role that CT has played in enhancing the depth of our understanding of disease have been profound. Although almost 90 000 articles on CT have been published in peer-reviewed journals over the past 40 years, fewer than 5% of these have been published in Radiology. Nevertheless, these almost 4000 articles have provided a basis for many important medical advances. By enabling a deepened understanding of anatomy, physiology, and pathology, CT has facilitated key advances in the detection and management of disease. This article celebrates this breadth of scientific discovery and development by examining the impact that CT has had on the diagnosis, characterization, and management of a sampling of major health challenges, including stroke, vascular diseases, cancer, trauma, acute abdominal pain, and diffuse lung diseases, as related to key technical advances in CT and manifested in Radiology.

Value of short-interval computed tomography when sonography fails to visualize the appendix and shows otherwise normal findings

OBJECTIVES

The purpose of this study was to evaluate the type and incidence of disorders revealed by short-interval computed tomography (CT) in patients with suspected appendicitis after graded compression sonography fails to reveal the appendix and shows otherwise normal findings.

METHODS

Computed tomographic findings and clinical courses were assessed retrospectively for 318 patients identified consecutively in a searchable database who met inclusion criteria specifying that sonography was the initial imaging examination for suspected appendicitis; sonography revealed nonvisualization of the appendix and otherwise normal results; and abdominopelvic CT was performed within 48 hours after sonography.

RESULTS

Of the 318 patients, short-interval CT revealed normal findings in 250 (78.6%). Appendicitis was revealed in 52 (16.4%) others, of whom 7 had perforation and all of whom had pathologic results confirming these CT findings. Important alternative diagnoses other than appendicitis were revealed in 16 (5.0%) others, including 2 (0.6%) who required urgent surgery and 14 (4.4%) who did not. No significant differences were observed between adult patients (>18 years) and pediatric patients.

CONCLUSIONS

Most short-interval CT scans in this clinical setting reveal normal findings, and relatively few disclose appendicitis or disorders that require urgent surgery. In view of concerns regarding radiation exposure associated with CT, these observations argue for the development of clinical triage methods that differentiate patients who are likely to benefit from short-interval postsonography CT from those who are not.

Diagnostic performance of contrast-enhanced MR for acute appendicitis and alternative causes of abdominal pain in children

OBJECTIVE

Unenhanced MRI has emerged as a useful tool for diagnosing pediatric acute appendicitis. The use of contrast-enhanced MRI for diagnosing pediatric appendicitis has not been documented. The purpose of this study is to examine the diagnostic performance of contrast-enhanced MRI for acute appendicitis and alternative entities in the pediatric population presenting with acute abdominal pain.

MATERIALS AND METHODS

A retrospective review was conducted of 364 consecutive pediatric patients undergoing contrast-enhanced MRI for the evaluation of possible appendicitis at a single institution between November 2012 and September 2013.

RESULTS

There were 132 cases of pathologically confirmed appendicitis out of 364 pediatric patients (36.3%) included in the study. Overall sensitivity and specificity were 96.2% (95% CI [91.4-98.4%]) and 95.7% (95% CI [92.3-97.6%]), respectively. Positive predictive value and negative predictive value were 92.7% (95% CI [86.6-96.3%]) and 97.8% (95% CI [94.7-99.1%]), respectively. The appendix was visualized in 243 cases (66.8%). Imaging confirmed alternative diagnoses in 75 patients, including most commonly colitis, enteritis or terminal ileitis (n = 25, 6.9%), adnexal cysts (n = 25, 6.9%) and mesenteric adenitis (n = 7, 1.9%).

CONCLUSION

Contrast-enhanced MRI is capable of accurately diagnosing acute appendicitis while detecting many alternative entities of abdominal pain, and it allows good visualization of the appendix. Further evaluation is needed to determine whether contrast-enhanced MRI provides an advantage over non-enhanced MRI for imaging evaluation of acute abdominal pain in the pediatric population.

Sonography of the normal appendix: its varied appearance and techniques to improve its visualization

The sonographic identification of the normal appendix is crucial to the success of ultrasound as an effective screening method for diagnosing acute appendicitis. The normal appendix can be challenging to identify on sonography, however, because it is a narrow tubular structure and has variable sonographic appearances. Moreover, the tip of the appendix can be quite variable in location. In this article, we review the various sonographic appearances of the normal appendix and highlight strategies to improve its visualization.