US or CT for Diagnosis of Appendicitis in Children and Adults? A Meta-Analysis

Diagnosis and management of complicated intra-abdominal infection in adults and children: guidelines by the Surgical Infection Society and the Infectious Diseases Society of America

Evidence-based guidelines for managing patients with intra-abdominal infection were prepared by an Expert Panel of the Surgical Infection Society and the Infectious Diseases Society of America. These updated guidelines replace those previously published in 2002 and 2003. The guidelines are intended for treating patients who either have these infections or may be at risk for them. New information, based on publications from the period 2003-2008, is incorporated into this guideline document. The panel has also added recommendations for managing intra-abdominal infection in children, particularly where such management differs from that of adults; for appendicitis in patients of all ages; and for necrotizing enterocolitis in neonates.

Unenhanced MR Imaging in adults with clinically suspected acute appendicitis

PURPOSE

The purpose of the study was to evaluate unenhanced Magnetic Resonance Imaging (MRI) for the diagnosis of appendicitis or another surgery-requiring condition in an adult population scheduled for emergency appendectomy based on a clinical diagnosis of suspected acute appendicitis.

MATERIALS AND METHODS

The prospective study included 48 consecutive patients (29 female, 19 male, 18-70 years old, mean age=37.1 years). MRI examination was designed to be comfortable and fast; no contrast was administered. The sequences were performed during quiet respiration. The MRI findings were reviewed by two radiologists and one surgeon independent of each other and compared with surgical and pathological records.

RESULTS

According to the surgical and histopathological findings 30 of 48 patients (63%) had acute appendicitis. Of the remaining 18 patients, 4 patients had no reasons for the clinical symptoms and 14 patients had other pathology. For the three reviewers the performance of MRI in the diagnosis of acute appendicitis showed the following sensitivity, specificity and accuracy ranges: 83-93%, 50-83% and 77-83%. Moderate (κ=0.51) and fair (κ=0.31) interobserver agreements in the MR diagnosis of acute appendicitis were found between the reviewers. Sensitivity, specificity and accuracy values for overall performance of MRI in detecting pelvic abnormalities were 100%, 75% (3 of 4 healthy patients were identified by MRI) and 98%, respectively.

CONCLUSION

Unenhanced fast MRI is feasible as an additional fast screening before the appendectomy. It may prevent unnecessary surgeries. The fast MRI examination can be adequately performed on an MRI unit of broad range of field strengths.

A focus on intra-abdominal infections

Complicated intra-abdominal infections are an important cause of morbidity and are frequently associated with poor prognosis, particularly in higher risk patients.

Well defined evidence-based recommendations for intra-abdominal infections treatment are partially lacking because of the limited number of randomized-controlled trials.

Factors consistently associated with poor outcomes in patients with intra-abdominal infections include increased illness severity, failed source control, inadequate empiric antimicrobial therapy and healthcare-acquired infection.

Early prognostic evaluation of complicated intra-abdominal infections is important to select high-risk patients for more aggressive therapeutic procedures.

The cornerstones in the management of complicated intra-abdominal infections are both source control and antibiotic therapy.

The timing and the adequacy of source control are the most important issues in the management of intra-abdominal infections, because inadequate and late control of septic source may have a negative effect on the outcomes.

Recent advances in interventional and more aggressive techniques could significantly decrease the morbidity and mortality of physiologically severe complicated intra-abdominal infections, even if these are still being debated and are yet not validated by limited prospective trials.

Empiric antimicrobial therapy is nevertheless important in the overall management of intra-abdominal infections. Inappropriate antibiotic therapy may result in poor patient outcomes and in the appearance of bacterial resistance.

Antimicrobial management is generally standardised and many regimens, either with monotherapy or combination therapy, have proven their efficacy. Routine coverage especially against Enterococci and candida spp is not always recommended, but can be useful in particular clinical conditions. A de escalation approach may be recommended in patients with specific risk factors for multidrug resistant infections such as immunodeficiency and prolonged antibacterial exposure.

Therapy should focus on the obtainment of adequate source control and adequate use of antimicrobial therapy dictated by individual patient risk factors. Other critical issues remain debated and more controversies are still open mainly because of the limited number of randomized controlled trials.

Management of acute appendicitis: an imaging strategy in children

The pre-operative diagnosis of acute appendicitis (AA) has markedly changed during the last couple of decades due to the advent of modern imaging technology. Nowadays, the use of imaging has dramatically changed the way we approach children admitted to emergency room for abdominal pain with suspected AA. This change is mainly manifested in our diagnostic strategy.

Diagnosis and Management of Complicated Intra-abdominal Infection in Adults and Children: Guidelines by the Surgical Infection Society and the Infectious Diseases Society of America

Evidence-based guidelines for managing patients with intra-abdominal infection were prepared by an Expert Panel of the Surgical Infection Society and the Infectious Diseases Society of America. These updated guidelines replace those previously published in 2002 and 2003. The guidelines are intended for treating patients who either have these infections or may be at risk for them. New information, based on publications from the period 2003–2008, is incorporated into this guideline document. The panel has also added recommendations for managing intra-abdominal infection in children, particularly where such management differs from that of adults; for appendicitis in patients of all ages; and for necrotizing enterocolitis in neonates.

High-risk chief complaints III: abdomen and extremities

Abdominal and extremity complaints are a frequent reason for presentation to the emergency department. Although these are common complaints, several abdominal and extremity disease entities may be missed or may be subject to delayed diagnosis. This article provides an overview of the diagnosis and management of several high-risk abdominal and extremity complaints, including appendicitis, abdominal aortic aneurysm, mesenteric ischemia, bowel obstruction, retained foreign body, hand and finger lacerations, fractures, and compartment syndrome. Each section focuses primarily on the pitfalls in diagnosis by highlighting the limitations of history, physical examination findings, and diagnostic testing and provides specific risk management strategies.

Discovery and validation of urine markers of acute pediatric appendicitis using high-accuracy mass spectrometry

STUDY OBJECTIVE

Molecular definition of disease has been changing all aspects of medical practice, from diagnosis and screening to understanding and treatment. Acute appendicitis is among many human conditions that are complicated by the heterogeneity of clinical presentation and shortage of diagnostic markers. Here, we sought to profile the urine of patients with appendicitis, with the goal of identifying new diagnostic markers.

METHODS

Candidate markers were identified from the urine of children with histologically proven appendicitis by using high-accuracy mass spectrometry proteome profiling. These systemic and local markers were used to assess the probability of appendicitis in a blinded, prospective study of children being evaluated for acute abdominal pain in our emergency department. Tests of performance of the markers were evaluated against the pathologic diagnosis and histologic grade of appendicitis.

RESULTS

Test performance of 57 identified candidate markers was studied in 67 patients, with median age of 11 years, 37% of whom had appendicitis. Several exhibited favorable diagnostic performance, including calgranulin A (S100-A8), alpha-1-acid glycoprotein 1 (orosomucoid), and leucine-rich alpha-2-glycoprotein (LRG), with the receiver operating characteristic area under the curve and values of 0.84 (95% confidence interval [CI] 0.72 to 0.95), 0.84 (95% CI 0.72 to 0.95), and 0.97 (95% CI 0.93 to 1.0), respectively. LRG was enriched in diseased appendices, and its abundance correlated with severity of appendicitis.

CONCLUSION

High-accuracy mass spectrometry urine proteome profiling allowed identification of diagnostic markers of acute appendicitis. Usage of LRG and other identified biomarkers may improve the diagnostic accuracy of clinical evaluations of appendicitis.

[Acute appendicitis. Modern diagnostics--surgical ultrasound]

Acute appendicitis is one of the most common acute surgical conditions of the abdomen. Nevertheless, the indications for appendectomy are associated with a high preoperative rate of false diagnoses. Although the rate of unnecessary appendectomies is comparatively high (20-30%) it is considered acceptable because the rate of perforated appendices is 7-30%. With good availability and lack of radiation exposure, ultrasound is the slice imaging modality of first choice. The sensitivity of ultrasonic detection of appendicitis lies between 55 and 98% and the specificity between 78 and 100%. Computed tomography (CT) has a significantly higher sensitivity for detecting acute appendicitis compared to ultrasound both in infancy and adulthood but the specificity shows no significant differences. CT is, therefore, the imaging modality of choice in cases of relevant differential diagnosis that cannot be visualized adequately or inconclusively by sonography especially in obese and critically ill patients. Comparison of ultrasound and magnet resonance imaging (MRI) revealed a significant advantage for MRI regarding accuracy, sensitivity and negative predictive value. In contrast, specificity and positive predictive value showed no significant differences. Currently MRI is only an alternative imaging modality to ultrasound in cases of undetermined and inconclusive ultrasonic findings especially in childhood and pregnancy. The value of ultrasound in the diagnosis of acute appendicitis is increasing and, particularly in the hands of experienced investigators, is an important imaging modality which delivers important and decision-making findings. Nevertheless, the final decision for appendectomy depends on the findings of the physical examination.

[Ultrasound and CT imaging in the diagnosis of acute appendicitis]

The diagnosis of acute appendicitis is still made on the basis of clinical findings in the majority of cases. When the clinical picture is unclear, ultrasound examination is a simple and effective tool to confirm the diagnosis. When ultrasound is unsatisfactory due to patient habitus or otherwise fails to clarify clinical uncertainty, abdominopelvic CT scan yields excellent results in terms of both sensitivity and specificity. While recognizing these evidence-based results, the surgeon must remain pragmatic and realize that the quality of each exam depends on the quality of the examination and the experience of the radiologist.

Diagnostic accuracy of noncontrast computed tomography for appendicitis in adults: a systematic review

STUDY OBJECTIVE

We seek to determine the diagnostic test characteristics of noncontrast computed tomography (CT) for appendicitis in the adult emergency department (ED) population.

METHODS

We conducted a search of MEDLINE, EMBASE, the Cochrane Library, and the bibliographies of previous systematic reviews. Included studies assessed the diagnostic accuracy of noncontrast CT for acute appendicitis in adults by using the final diagnosis at surgery or follow-up at a minimum of 2 weeks as the reference standard. Studies were included only if the CT was completed using a multislice helical scanner. Two authors independently conducted the relevance screen of titles and abstracts, selected studies for the final inclusion, extracted data, and assessed study quality. Consensus was reached by conference, and any disagreements were adjudicated by a third reviewer. Unenhanced CT test performance was assessed with summary receiver operating characteristic curve analysis, with independently pooled sensitivity and specificity values across studies.

RESULTS

The search yielded 1,258 publications; 7 studies met the inclusion criteria and provided a sample of 1,060 patients. The included studies were of high methodological quality with respect to appropriate patient spectrum and reference standard. Our pooled estimates for sensitivity and specificity were 92.7% (95% confidence interval 89.5% to 95.0%) and 96.1% (95% confidence interval 94.2% to 97.5%), respectively; the positive likelihood ratio=24 and the negative likelihood ratio=0.08.

CONCLUSION

We found the diagnostic accuracy of noncontrast CT for the diagnosis of acute appendicitis in the adult population to be adequate for clinical decisionmaking in the ED setting.

Single and combined diagnostic value of clinical features and laboratory tests in acute appendicitis

OBJECTIVES

The objective was to evaluate the diagnostic accuracy of clinical features and laboratory test results in detecting acute appendicitis.

METHODS

Clinical features and laboratory test results were prospectively recorded in a consecutive series of 1,101 patients presenting with abdominal pain at the emergency department (ED) in six hospitals. Likelihood ratios (LRs) and the areas under the receiver operating characteristic curve (AUC) were calculated for the individual features. Variants of clinical presentation, based on different combinations of clinical features, were investigated and the accuracies of combinations of clinical features were evaluated.

RESULTS

The discriminative power (AUC) of the individual features in patients with suspected appendicitis ranged from 0.50 to 0.65. For five of the 23 predictor sets, the accuracy for appendicitis was more than 85%. This accuracy was only found in male patients. The relative frequency of these predictor sets ranged from 2% to 13% of patients with suspected appendicitis. A combination of the clinical features migration of pain to the right lower quadrant (RLQ), and direct tenderness in the RLQ, was present in only 28% (120/422) of clinically suspected patients, of whom no more than 85 patients had appendicitis (71%). A "classical" presentation (combination of migration of pain to the RLQ, tenderness in the RLQ, and rigidity) occurred in only 6% (25/422) of patients with suspected appendicitis and yielded an accuracy of 100% in males but only 46% in females.

CONCLUSIONS

The discriminative power (AUC) of individual clinical features and laboratory test results for appendicitis was weak in patients with suspected appendicitis. Combinations of clinical features and laboratory tests with high diagnostic accuracy are relatively infrequent in patients with suspected appendicitis.

Appendiceal hyperemia and/or distention is not always appendicitis: appendicitis mimicry in the pediatric population

Appendicitis is the most common surgical cause of acute abdominal pain in the pediatric population. Several conditions can mimic the clinical presentation of appendicitis, leaving imaging as an essential modality to uncover the etiology, yet under certain circumstances, it can be misleading. Here, we present three cases where findings on multidetector computerized tomography scans supported the diagnosis of appendicitis, yet an alternate cause was found. These cases highlight a particular pitfall of satisfaction of search.

Prospective validation of the pediatric appendicitis score in a Canadian pediatric emergency department

OBJECTIVES

Clinical scoring systems attempt to improve the diagnostic accuracy of pediatric appendicitis. The Pediatric Appendicitis Score (PAS) was the first score created specifically for children and showed excellent performance in the derivation study when administered by pediatric surgeons. The objective was to validate the score in a nonreferred population by emergency physicians (EPs).

METHODS

A convenience sample of children, 4-18 years old presenting to a pediatric emergency department (ED) with abdominal pain of less than 3 days' duration and in whom the treating physician suspected appendicitis, was prospectively evaluated. Children who were nonverbal, had a previous appendectomy, or had chronic abdominal pathology were excluded. Score components (right lower quadrant and hop tenderness, anorexia, pyrexia, emesis, pain migration, leukocytosis, and neutrophilia) were collected on standardized forms by EPs who were blinded to the scoring system. Interobserver assessments were completed when possible. Appendicitis was defined as appendectomy with positive histology. Outcomes were ascertained by review of the pathology reports from the surgery specimens for children undergoing surgery and by telephone follow-up for children who were discharged home. Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were calculated. The overall performance of the score was assessed by a receiver operator characteristic (ROC) curve.

RESULTS

Of the enrolled children who met inclusion criteria (n = 246), 83 (34%) had pathology-proven appendicitis. Using the single cut-point suggested in the derivation study (PAS 5) resulted in an unacceptably high number of false positives (37.6%). The score's performance improved when two cut-points were used. When children with a PAS of <or=4 were discharged home without further investigations, the sensitivity was 97.6% with a NPV of 97.7%. When a PAS of >or=8 determined the need for appendectomy, the score's specificity was 95.1% with a PPV of 85.2%. Using this strategy, the negative appendectomy rate would have been 8.8%, the missed appendicitis rate would have been 2.4%, and 41% of imaging investigations would have been avoided.

CONCLUSIONS

The PAS is a useful tool in the evaluation of children with possible appendicitis. Scores of <or=4 help rule out appendicitis, while scores of >or=8 help predict appendicitis. Patients with a PAS of 5-7 may need further radiologic evaluation.

Evaluating routine diagnostic imaging in acute appendicitis

AIM

To evaluate the impact of selective imaging on clinical management of patients who present with symptoms suggesting acute appendicitis.

MATERIALS AND METHODS

During a two-and-half year period, 941 consecutive patients with right lower quadrant pain were analyzed. Patients who underwent selective imaging were compared to those treated without further imaging.

RESULTS

In 650 (69%) patients with right lower quadrant pain, diagnosis was based on medical history, physical and laboratory examination only. The diagnostic accuracy was 84%. Another 291 patients (31%) underwent selective imaging reaching a diagnostic accuracy of 71%. Ultrasound was conducted in 277 patients (sensitivity: 59%; specificity: 91%). CT scan was conducted in 43 patients (sensitivity: 100%; specificity: 95%).

CONCLUSION

The present study shows that, in the majority of patients, appendicitis acuta can be diagnosed without the aid of imaging studies. In all these cases, high diagnostic accuracy rates and low morbidity rates were achieved. In all the other cases when clinical diagnosis is uncertain, further evaluation should include imaging. In our series ultrasound is of limited value; CT scan or diagnostic laparoscopy seems superior.

Diagnostic value of maximal-outer-diameter and maximal-mural-thickness in use of ultrasound for acute appendicitis in children

AIM: To evaluate the maximal-outer-diameter (MOD) and the maximal-mural-thickness (MMT) of the appendix in children with acute appendicitis and to determine their optimal cut-off values to diagnose acute appendicitis.

METHODS: In total, 164 appendixes from 160 children between 1 and 17 years old (84 males, 76 females; mean age, 7.38 years) were examined by high-resolution abdominal ultrasound for acute abdominal pain and the suspicion of acute appendicitis. We measured the MOD and the MMT at the thickest point of the appendix. Patients were categorized into two groups according to their medical records: patients who had surgery (surgical appendix group) and patients who did not have surgery (non-surgical appendix group). Data were analyzed by MedCalc v.9.3. The rank sum test (Mann-Whitney test) was used to evaluate the difference in the MOD and the MMT between the two groups. ROC curve analysis was used to determine the optimal cut-off value of the MOD and the MMT on diagnosis of acute appendicitis.

RESULTS: There were 121 appendixes (73.8%) in the non-surgical appendix group and 43 appendixes (26.2%) in the surgical appendix group. The median MOD differed significantly between the two groups (0.37 cm vs 0.76 cm, P < 0.0001), and the median MMT also differed (0.15 cm vs 0.33 cm, P < 0.0001). The optimal cut-off value of the MOD and the MMT for diagnosis of acute appendicitis in children was > 0.57 cm (sensitivity 95.4%, specificity 93.4%) and > 0.22 cm (sensitivity 90.7%, specificity 79.3%), respectively.

CONCLUSION: The MOD and the MMT are reliable criteria to diagnose acute appendicitis in children. An MOD > 0.57 cm and an MMT > 0.22 cm are the optimal criteria.

ACR Appropriateness Criteria on acute pelvic pain in the reproductive age group

Premenopausal women who present with acute pelvic pain frequently pose a diagnostic dilemma, exhibiting nonspecific signs and symptoms, the most common being nausea, vomiting, and leukocytosis. Diagnostic considerations encompass multiple organ systems, including obstetric, gynecologic, urologic, gastrointestinal, and vascular etiologies. The selection of imaging modality is determined by the clinically suspected differential diagnosis. Thus, a careful evaluation of such a patient should be performed and diagnostic considerations narrowed before a modality is chosen. Transvaginal and transabdominal pelvic sonography is the modality of choice when an obstetric or gynecologic abnormality is suspected, and computed tomography is more useful when gastrointestinal or genitourinary pathology is more likely. Magnetic resonance imaging, when available in the acute setting, is favored over computed tomography for assessing pregnant patients for nongynecologic etiologies because of the lack of ionizing radiation.

Imaging of acute appendicitis in children: EU versus U.S. ... or US versus CT? A European perspective

There is substantial evidence that imaging may reduce the negative appendectomy rate, also in children. However, controversy exists about the preferred method: US or CT, and the choice appears to be determined by the side of the Atlantic Ocean. This review brings forth several arguments in favour of US.

Imaging of acute appendicitis in children: EU versus U.S. ... or US versus CT? A North American perspective

The timing, type, and technique of imaging evaluation of suspected appendicitis in children are all debated. This debate is both local and international. The fact is that choices in imaging evaluation will depend on both local and national influences, which are reasonable and to be expected. There still is a responsibility, though, for those involved with evaluation of patients with possible appendicitis to come to agreement about an appropriate diagnostic pathway that considers standards of care and available resources.

Improving diagnosis of acute appendicitis: results of a diagnostic pathway with standard use of ultrasonography followed by selective use of CT

BACKGROUND

Preoperative imaging has been demonstrated to improve diagnostic accuracy in appendicitis. This prospective study assessed the accuracy of a diagnostic pathway in acute appendicitis using ultrasonography (US) and complementary contrast-enhanced multidetector CT in a general community teaching hospital.

STUDY DESIGN

One hundred fifty-one patients with clinically suspected appendicitis followed the designed protocol: patients underwent operations after a primary performed positive US (graded compression technique) or after complementary CT (contrast-enhanced multidetector CT) when US was negative or inconclusive. Patients with positive CT findings underwent operations. When CT was negative for appendicitis, they were admitted for observation. Results of US and CT were correlated with surgical findings, histopathology, and followup.

RESULTS

Positive US was confirmed at operation in 71 of 79 patients and positive CT was confirmed in all 21 patients. All 39 patients with negative CT findings recovered without operations. The negative appendicitis rate was 8% and perforation rate was 9%. The sensitivity and specificity of US was 77% and 86%, respectively. The sensitivity and specificity of CT was both 100%. The sensitivity and specificity of the whole diagnostic pathway was 100% and 86%, respectively.

CONCLUSIONS

A diagnostic pathway using primary graded compression US and complementary multidetector CT in a general community teaching hospital yields a high diagnostic accuracy for acute appendicitis without adverse events from delay in treatment. Although US is less accurate than CT, it can be used as a primary imaging modality, avoiding the disadvantages of CT. For those patients with negative US and CT findings, observation is safe.

Optimizing the role of imaging in appendicitis

Acute appendicitis is the most common acute abdominal condition that requires surgical intervention in childhood. From the diagnostic performance perspective, computed tomography (CT) has a significantly higher sensitivity than does ultrasound (US) for diagnosing appendicitis in children; from the safety perspective, however, one should consider the radiation associated with CT, especially in children. There is strong evidence supporting improved patient outcomes in children with suspected acute appendicitis who undergo CT scanning. Nevertheless, we should keep in mind that for a single abdominal CT study in a 5-year-old child, the lifetime risk of radiation-induced cancer would be 26.1 per 100,000 in female and 20.4 per 100,000 in male patients, based on probabilistic models designed with data from atomic bomb survivors. An integrated clinical-imaging approach, applying clinical scores that are able to predict which children with acute abdominal pain do or do not have a high probability of presenting with appendicitis may improve the effectiveness of the imaging diagnosis of appendicitis at the hospital level. Such an approach could avoid exposure of children who at low risk for appendicitis to unnecessary diagnostic tests and eventually, to radiation.

The appendix on CT

Appendicitis can be a difficult clinical diagnosis to make. A negative appendicectomy rate of 20% has traditionally been accepted as the consequences of appendiceal perforation can be grave. Cross-sectional imaging is increasingly being employed in the investigation of adults with suspected appendicitis. This review will demonstrate the appearance of the normal appendix on computed tomography (CT) and its appearance in a range of inflammatory and neoplastic processes including appendicitis, Crohn's disease, infections, and benign and malignant tumours.

A simple MRI protocol in patients with clinically suspected appendicitis: results in 138 patients and effect on outcome of appendectomy

To establish the value of breathhold magnetic resonance imaging (MRI) in the diagnosis of acute appendicitis. Over a 14-month period, 138 patients clinically suspected of having appendicitis were evaluated prospectively with MRI and comprised the study group. Fast turbo spin-echo breathhold T1, T2 and T2 fat suppression sequences were used in coronal and axial planes. The imaging results were recorded separately and subsequently correlated with clinical, radiological and histopathological follow-up. The effect of imaging strategies in patients suspected of appendicitis on hospital resources was calculated. Sixty-two of the 138 patients had a histopathologically proven appendicitis. MRI determined appendicitis in 63 patients, with one examination being false positive. The resulting sensitivity and specificity were 100% and 99%, respectively. MRI showed an alternative diagnosis in 41 of the 75 remaining patients. In 22 of the remaining 34 patients, a normal appendix was depicted with MRI. In two patients, where MRI showed no appendicitis, an alternative diagnosis or normal appendix, an unnecessary appendectomy was performed. The overall effect of using MRI in patients suspected of appendicitis on the use of hospital resources could have been a net saving between 55,746 euros and 72,534 euros. MRI has a high accuracy in detecting and excluding appendicitis, an alternative diagnosis or showing the normal appendix, and can be a valuable and cost-effective tool in the workup of patients clinically suspected of having appendicitis.

Acute appendicitis in young children: cost-effectiveness of US versus CT in diagnosis--a Markov decision analytic model

PURPOSE

To compare the cost-effectiveness of different imaging strategies in the diagnosis of pediatric appendicitis by using a decision analytic model.

MATERIALS AND METHODS

Approval for this retrospective study based on literature review was not required by the institutional Research Ethics Board. A Markov decision model was constructed by using costs, utilities, and probabilities from the literature. The risk of radiation-induced cancer was modeled by using the Biological Effects of Ionizing Radiation VII report, which is based primarily on data from atomic bomb survivors. The three imaging strategies were ultrasonography (US), computed tomography (CT), and US followed by CT if the initial US study was negative. The model simulated the short-term and long-term outcomes of the patients, calculating the average quality-adjusted life span and health care costs.

RESULTS

For a single abdominal CT study in a 5-year-old child, the lifetime risk of radiation-induced cancer would be 26.1 per 100,000 in female and 20.4 per 100,000 in male patients. In the base-case analysis, US followed by CT was the most costly and most effective strategy, CT was the second-most costly and second-most effective strategy, and US was the least costly and least effective strategy. The incremental cost-effectiveness ratios (ICERs) of CT to US and of US followed by CT to US were both well below the societal willingness-to-pay threshold of $50,000 (in U.S. dollars). The ICER of US followed by CT to CT was less than $10,000 in both male and female patients.

CONCLUSION

In a Markov-based decision model of pediatric appendicitis, the most cost-effective method of imaging pediatric appendicitis was to start with a US study and follow each negative US study with a CT examination.

Diagnosing acute appendicitis: are we overusing radiologic investigations?

PURPOSE

Acute appendicitis is the most common emergency presenting to pediatric surgeons. With proper history and thorough physical examination, the diagnosis of the condition clinically should approach 90%. With the increasing ease of performing radiologic investigations because of technological advances, more ultrasound and computed tomography (CT) are used to help diagnosing appendicitis. The aim of this study is to review the trend of diagnosing appendicitis in a single center and discuss the implications.

METHODS

A retrospective analysis was carried out for all patients who were admitted with acute appendicitis between 1997 and 2007. The methods of diagnosis were divided into 3 groups as follows: clinical, ultrasound, and CT. The demographics and operative findings were noted. Statistical analysis was done using Fisher's Exact test and paired t test when appropriate. A value of P < .05 was considered to be statistically significant.

RESULTS

During this period, a total of 254 patients (167 boys and 87 girls) were admitted with appendicitis. The average age at presentation was 12 years, and the mean duration of symptoms before presentation was 2 days. For 11 years, there was an initial rise of the use of ultrasound (10% in 1997 to a peak of 60% in 2005). This percentage decreased with a corresponding rise of the use of CT scan (0% in 1997 to 35% in 2007). There was no correlation found between the use of adjunct investigations and the severity of appendicitis found at operation, suggesting an overreliance of CT.

CONCLUSION

It appears that there is an increasing trend in using radiologic investigations for the diagnosis of appendicitis for the past 11 years. With the association of cancer in later life and early radiation exposure well documented, it would be advisable to avoid the use of CT if possible.

Imaging utilization commentary: a radiology perspective

To adhere to the ALARA concept, imaging should be limited to studies that actually contribute to the management of the patient. For example, by applying the Ottawa Ankle Rule and the Ottawa Knee Rule, fewer radiographs are required to evaluate ankle and knee trauma in children. Chest radiographs usually do not contribute to the management of children presenting with typical acute bronchiolitis or asthma, and they can be detrimental because consolidation resulting from retained secretions is interpreted as pneumonia and the child is started on antibiotics unnecessarily. Moreover, a radiograph of the abdomen has poor validity and reproducibility for the diagnosis of constipation. The Pediatric Emergency Care Applied Research Network (PECARN) and the Pediatric Emergency Research in Canada (PERC) are currently developing decision rules for the use of CT in the assessment of minor head injuries in children, which should reduce its utilization in this condition. PECARN is also developing a decision rule for the use of CT in the assessment of abdominal trauma in children. CT is frequently used for the diagnosis of appendicitis in children, but appendicitis can be diagnosed clinically. If imaging is required, appendicitis can often be diagnosed with US, and CT need only be used in the minority of cases where the diagnosis is still in doubt. Utilization guidelines for pediatric imaging studies obtained in children in the emergency setting can improve yield and help in the more efficient management of often scarce health care resources.

Contemporary imaging in abdominal emergencies

Imaging is often a fundamental part in the evaluation of an injured or ill child. A variety of imaging modalities (radiography, angiography/fluoroscopy, sonography, CT, magnetic resonance imaging and scintigraphy) are among the options. CT is worth focused attention because of its usefulness in a variety of emergency department settings, its increasing use, and its potential radiation risks. CT plays an important role in the evaluation of traumatic and nontraumatic abdominal emergencies in children. Therefore, the goal of this paper is to review current imaging approaches and controversies in the evaluation of common acute abdominal emergencies. Through discussion of various modalities, especially CT in evaluation of abdominal pain and trauma, the relative advantages and disadvantages including radiation risk will be reviewed.

US examination of the appendix in children with suspected appendicitis: the additional value of secondary signs

This study evaluated the additional value of secondary signs in the diagnosing of appendicitis in children with ultrasound. From May 2005 to June 2006, 212 consecutive paediatric patients with suspected appendicitis were examined. Ultrasonographic depiction of the appendix was classified into four groups: 1, normal appendix; 2, appendix not depicted, no secondary signs of appendicitis; 3, appendix not depicted with one of the following secondary signs: hyperechoic mesenteric fat, fluid collection, local dilated small bowel loop; 4, depiction of inflamed appendix. We classified 96 patients in group 1, 41 in group 2, 13 in group 3, and 62 in group 4. Prevalence of appendicitis was 71/212 (34%). Negative predictive values of groups 1 and 2 were 99% and 100%, respectively. Positive predictive values of groups 3 and 4 were 85% and 95%, respectively. In groups 3 and 4, hyperechoic mesenteric fat was seen in 73/75 (97.3%), fluid collections and dilated bowel loops were seen in 12/75 (16.0%) and 5/75 (6.6%), respectively. This study shows that in case of non-visualization of the appendix without secondary signs, appendicitis can be safely ruled out. Furthermore, secondary signs of appendicitis alone are a strong indicator of acute appendicitis.

Abnormal computed tomography findings among children with viral gastroenteritis and symptoms mimicking acute appendicitis

OBJECTIVE

To evaluate computed tomography (CT) findings in pediatric patients with viral gastroenteritis who presented with clinical features of acute abdomen.

PATIENTS AND METHODS

During 2 seasons of viral gastroenteritis from 2005 to 2007, 302 children with acute gastrointestinal symptoms were admitted to our center for treatment of dehydration and associated complications. Stool specimens obtained from 130 of the 302 were tested for norovirus with the reverse transcriptase-polymerase chain reaction method.

RESULTS

Among the 130 patients, 44 tested positive for norovirus, 34 for rotavirus, and 1 for adenovirus. In the remaining 51, except one with Campylobacter jejuni, no viral or bacterial pathogen was detectable. An abdominal CT scan was performed in 4 patients with norovirus and in 1 with rotavirus for suspected acute abdomen including acute appendicitis. Computed tomography (CT) findings were similar among the 5 patients, including thickening of the bowel wall and fluid-filled bowel loops in the small intestine with no pathological findings in the stomach, appendix, or colon.

CONCLUSIONS

Anatomical changes in the small intestine were shown by CT in 5 children with viral gastroenteritis who presented with acute abdomen. These imaging features of viral gastroenteritis may be useful in differential diagnosis of acute abdomen to avoid unnecessary surgery.

MR imaging evaluation of the normal appendix in children and adolescents

PURPOSE

To evaluate asymptomatic children and adolescents to determine the rate of detection of the normal appendix at unenhanced magnetic resonance (MR) imaging.

MATERIALS AND METHODS

This study was approved by the medical ethics committees of the authors' institutions, and informed consent was obtained from participants' parents or guardians. Forty asymptomatic volunteers underwent MR imaging to detect the appendix. Mean age (+/- standard deviation) for the 18 boys was 12.8 years +/- 2.4 (range, 9-17 years) and for the 22 girls was 12.7 years +/- 2.7 (range, 8-17 years). The MR imaging protocol consisted of axial T1-weighted fast spin-echo (SE), axial and coronal T2-weighted fast SE, and axial T2-weighted fat-saturated fast SE sequences. Two observers interpreted results independently, and kappa coefficients were calculated to evaluate agreement. The rate of detection was defined as the percentage of times that the appendix was visualized with at least one sequence. Body mass index was recorded for all participants.

RESULTS

The normal appendix was detected by one observer in 19 cases (48%) and by the other in 20 cases (50%). The rate of appendix detection after observers reached a consensus was 48% (95% confidence interval: 32%, 64%). Interobserver agreement for appendix detection was good for most sequences analyzed. The greatest rate of normal appendix detection was found with the axial T2-weighted fast SE sequence (48%).

CONCLUSION

The rate of normal appendix detection in children and adolescents at unenhanced MR imaging was 48%, which is similar to computed tomographic but lower than ultrasonographic detection rates.

Acute appendicitis: meta-analysis of diagnostic performance of CT and graded compression US related to prevalence of disease

PURPOSE

This study was a head-to-head comparison of graded compression ultrasonography (US) and computed tomography (CT) in helping diagnose acute appendicitis with an emphasis on diagnostic value at different disease prevalences, commonly occurring in various hospital settings.

MATERIALS AND METHODS

MEDLINE, EMBASE, CINAHL, and Cochrane databases were searched from January 1966 to February 2006. Prospective trials were selected if they (a) compared graded compression US and CT in the same patient population; (b) included more than 10 patients, otherwise, the study was considered a case report; (c) evaluated mainly adults or adolescents; (d) used surgery and/or clinical follow-up as reference standard; and (e) reported data to calculate 2 x 2 contingency tables for graded compression US and CT. Estimates of sensitivity, specificity, and positive and negative likelihood ratios (LRs) for US and CT were calculated. Posttest probabilities after CT and US were calculated for various clinically relevant prevalences.

RESULTS

Six studies were included, evaluating 671 patients (mean age range, 26-38 years); prevalence of acute appendicitis was 50% (range, 13%-77%). Positive LR was 9.29 (95% confidence interval [CI]: 6.9, 12.6) for CT and 4.50 (95% CI: 3.0, 6.7; P = .011) for US, yielding posttest probabilities for positive tests of 90% and 82%, respectively. Negative LR was 0.10 (95% CI: 0.06, 0.17) for CT and 0.27 (95% CI: 0.17, 0.43) for US (P = .013), resulting in posttest probabilities of 9% and 21%, respectively. Posttest probabilities for positive tests were markedly decreased at lower prevalences.

CONCLUSION

In head-to-head comparison studies of diagnostic imaging, CT had a better test performance than did graded compression US in diagnosing appendicitis. Ignoring the relationship between prevalence (pretest probability) and diagnostic value may lead to an inaccurate estimation of diagnostic performance.

Paediatric abdominal ultrasound

Ultrasound is widely used in the imaging of many paediatric conditions. Children are excellent candidates for ultrasound examination as they are generally smaller than adults with less body fat allowing excellent quality images to be obtained. In addition, ultrasound has several advantages over other cross-sectional imaging modalities used in paediatrics, including the lack of exposure to ionizing radiation, the avoidance of intravenous and oral contrast agents and the relative ease with which examinations can be performed without the need for sedation (De Bruyn, 2005). This article will focus on some aspects of paediatric abdominal ultrasound, namely renal tract abnormalities, common paediatric abdominal tumours and some common conditions presenting as acute abdominal emergencies.

Conservative management of acute appendicitis in children with hematologic malignancies during chemotherapy-induced neutropenia

The management of acute appendicitis in the febrile neutropenic patient after intensive chemotherapy is controversial. We report our single-center-experience of 5 children diagnosed with appendicitis during febrile neutropenia after chemotherapy for acute leukemia or lymphoma. All patients presented with an isolated appendicitis without signs of overt mucositis or more diffuse enterocolitis. The clinical diagnosis was confirmed by ultrasonography. Perforation with retrocecal abscess was present in 1 patient. Administration of combination antimicrobial regimens including meropenem resulted in complete resolution in all patients. Our observations indicate that acute appendicitis in clinically stable neutropenic cancer patients can be managed conservatively without surgery.

ALARA: is there a cause for alarm? Reducing radiation risks from computed tomography scanning in children

PURPOSE OF REVIEW

Radiation exposure from computed tomography is associated with a small but significant increase in risk for fatal cancer over a child's lifetime. This review aims to heighten awareness and spearhead efforts to reduce unnecessary computed tomography scans in children.

RECENT FINDINGS

The use of pediatric computed tomography continues to grow despite evidence on known risks of computed tomography-related radiation and induction of fatal cancers in children. More than 60 million computed tomography scans are estimated to be performed annually in the USA, with 7 million in children. Pediatric radiologists apply the practice of ALARA ('as low as reasonably achievable') to reduce radiation exposure. Education and advocacy directed to the referring clinician reinforce these principles. Radiation exposure may be further reduced by developing clinical pathways limiting computed tomography scanning and encourage alternate, nonradiation imaging modalities, such as ultrasound and magnetic resonance imaging. Although individual risk estimates are small, widespread use of computed tomography in the population may implicate a future public health issue.

SUMMARY

Advocacy by pediatric healthcare providers to promote intelligent dose reduction based on the principles of ALARA and the judicious use of computed tomography scanning is essential to foster the safest possible care of children.

Current management of appendicitis at a community center--how can we improve?

BACKGROUND

Controversies regarding the diagnosis and treatment of appendicitis remain. Practices and outcomes at a community center including imaging, timing of surgery, and surgical technique are reported.

METHODS

From January to July 2006, 134 patients undergoing appendectomy in Victoria, British Columbia, were reviewed. Accuracy of preoperative imaging, time from the emergency room to the operating room, length of stay, and early complications were analyzed. Patients with and without perforation were compared using sample t tests.

RESULTS

Preoperative computed tomography was obtained for 101 patients (75%) with a negative appendectomy rate of 3% versus 10% for patients without imaging. Imaging did not prolong the time to surgery (11.8 vs 10.9 h, P = .48). Patients with perforation stayed in the hospital significantly longer and had more complications.

CONCLUSIONS

The liberal use of computed tomography resulted in fewer negative appendectomies without a significant delay to surgery. Patients with perforation had increased complications and longer hospitalizations. Efforts should be made to identify and treat early appendicitis.