Acute appendicitis: sonographic criteria based on 250 cases

False-negative appendicitis at ultrasound: nature and association

The objective was to describe nature and factors associated with false-negative ultrasound (US) for adult appendicitis. Patients with pathologically proven appendicitis and pre-operative US from January 2011 to May 2013 were included in this retrospective case-control study. They were divided into true-positive and false-negative groups, matched by age and gender. There were 112 patients (40 men, mean age = 40 y, 56 true positives) included. Two factors were found differ significantly: abdominal wall thickness and pain score. Greater abdominal wall thickness (18.6 mm vs. 14.9 mm, p = 0.001) and lower pain score (6.6 vs. 7.5, p = 0.018) were statistically associated with false negativity. The two groups did not differ significantly in terms of weight, height, body mass index, symptom duration, Alvarado score, US examination time, appendix position/size, perforation rate and operator. In conclusion, lower pain score and increased abdominal wall thickness are associated with false negativity in US examinations.

Utility of CT after sonography for suspected appendicitis in children: integration of a clinical scoring system with a staged imaging protocol

To improve diagnosis of pediatric appendicitis, many institutions have implemented a staged imaging protocol utilizing ultrasonography (US) first and then computed tomography (CT). A substantial number of children with suspected appendicitis undergo CT after US, and the efficient and accurate diagnosis of pediatric appendicitis continues to be challenging. The objective of the study is to characterize the utility of CT following US for diagnosis of pediatric appendicitis, in conjunction with a clinical appendicitis score (AS). Imaging studies of children with suspected appendicitis who underwent CT after US in an imaging protocol were retrospectively reviewed by three radiologists in consensus. Chart review derived the AS (range 0-10) and obtained the patient diagnosis and disposition, and an AS was applied to each patient. Clinical and radiologic data were analyzed to assess the yield of CT after US. Studies of 211 children (mean age 11.3 years) were included. The positive threshold for AS was determined to be 6 out of 10. When AS and US were concordant (N = 140), the sensitivity and specificity of US were similar to CT. When AS and US were discordant (N = 71) and also when AS ≥ 6 (N = 84), subsequent CT showed superior sensitivity and specificity to US alone. In the subset where US showed neither the appendix nor inflammatory change in the right lower quadrant (126/211, 60 % of scans), when AS < 6 (N = 83), the negative predictive value (NPV) of US was 0.98. However, when AS ≥ 6 (N = 43), NPV of US was 0.58, and the positive predictive value of subsequent CT was 1. There was a significant decrease in depiction of the appendix on US with patient weight-to-age ratio of >6 (kg/year, P < 0.001) and after-hours (1700 -0730 hours) performance of US (P < 0.001). Results suggest that the appendicitis score has utility in guiding an imaging protocol and support the contention that non-visualization of the appendix on US is not intrinsically non-diagnostic. There was little benefit to additional CT when AS < 6 and US did not show the appendix or evidence of inflammation; this would have avoided CT in 140/211 (66 %) patients. CT demonstrated benefit when AS ≥ 6, suggesting that cases with AS ≥ 6 and features that limit depiction of the appendix on US may be triaged to CT.

Cystic fibrosis: unenhanced CT description of the appendix in asymptomatic adults

OBJECTIVE

The purpose of this study was to describe the unenhanced CT appearance of the appendix in adults with cystic fibrosis.

SUBJECTS AND METHODS

Among adults with cystic fibrosis undergoing follow-up at our hospital, 71 patients (35 women, 36 men; mean age, 33 years; range, 18-59 years) without a history of appendectomy or current abdominal pain were prospectively included in this study and underwent unenhanced abdominopelvic MDCT. Two readers coded visualization of the appendix, measured the diameter of the appendix, and described the attenuation of its contents in relation to the intestinal wall. They also coded the presence of colonic wall redundancy, pancreatic fatty replacement, and cirrhosis. Lung transplant status and CFTR gene mutations were recorded. Analysis of variance, linear regression analysis, Student t test, and Pearson test were used.

RESULTS

The appendix was detected in all patients. The mean diameter was recorded as 10.6 ± 3.5 mm. The mean diameter was larger when the appendix contained hyperattenuating material (p = 0.001). There was no association between diameter and the other coded CT findings (p = 0.076-0.466), transplant status (p = 0.788), or CFTR mutation (p = 0.078). In 75% of the patients, the appendix contained hyperattenuating material with a higher proportion in homozygous ΔF508 mutation (p = 0.029) without any significant effect of the other CT features (p = 0.056-0.392), or transplant status (p = 1.000).

CONCLUSION

The appendix is larger in adults with cystic fibrosis than in those without it and appears hyperattenuating at unenhanced CT in 75% of patients, more commonly in those with ΔF508 homozygous mutation.

US of the pediatric female pelvis

This review presents the normal and pathologic development of the gonads and genitourinary tract and addresses the role of ultrasonography in the diagnosis and management of gynecologic disorders of the pediatric pelvis, including ambiguous genitalia, prepubertal bleeding, primary amenorrhea, pelvic mass, and pelvic pain.

Integration of ultrasound findings with Alvarado score in children with suspected appendicitis

BACKGROUND

The aim of this study was to investigate the integration of ultrasound (US) findings with Alvarado score in diagnosing or excluding acute appendicitis.

METHODS

Data were analyzed in 122 pediatric patients with suspected appendicitis who had undergone US. The US findings were classified into four groups, and the patients were classified into three groups according to Alvarado score. US results and Alvarado score were compared.

RESULTS

Alvarado score was a good predictor of appendicitis for scores ≥7.

CONCLUSION

In the case of non-visualization of the appendix without a high Alvarado score, appendicitis can be safely ruled out.

Acute appendicitis: investigating an optimal outer appendiceal diameter cut-point in a pediatric population

BACKGROUND

Acute appendicitis is the most common cause of abdominal pain in children requiring operative intervention. Among a number of sonographic criteria to aid in the diagnosis of appendicitis, an outer diameter >6 mm is the most objective and widely accepted. However, there is a lack of evidence-based standards governing this consensus.

STUDY OBJECTIVES

The aim of this study was to determine the outer appendiceal diameter that maximizes sensitivity and specificity in a pediatric population.

METHODS

A retrospective review of all urgent diagnostic ultrasounds (US) was performed over 2 years in children aged <18 years. The diagnostic accuracy of various cut-points was assessed by calculating the sensitivity and specificity and plotting a receiver operating characteristic (ROC) curve.

RESULTS

The study sample consisted of 398 patients in whom the appendix was visualized on US. The median outer appendiceal diameter was significantly higher in the surgical group compared to the nonsurgical group (9.4 mm; range = 8.1-12.0 vs. 5.5 mm; range = 4.4-6.5, p < 0.01). The optimal cut-point with the greatest area under the ROC curve was determined to be an outer appendiceal diameter of 7.0 mm.

CONCLUSIONS

In our patients, adopting a 7-mm rather than a 6-mm appendiceal diameter threshold would balance a greater number of missed cases of acute appendicitis for a reduction in the number of unnecessary surgeries.

Appendiceal length as an independent risk factor for acute appendicitis

OBJECTIVES

To determine if appendiceal lengths differ between adults with acute appendicitis and asymptomatic controls.

METHODS

In vivo appendiceal length at computed tomography (CT) in 321 adults with surgically proven appendicitis was compared with that in 321 consecutive asymptomatic adult controls. CT length was derived using curved multiplanar reformats along the long axis. Gross pathological length provided external validation for appendectomy cases.

RESULTS

Appendiceal length at CT correlated well with appendicitis specimens (mean length, 6.8 cm vs 6.6 cm; 79 % within 1.5 cm). For asymptomatic controls, mean CT appendiceal length was 7.9 cm, longer in men (8.4 ± 3.8 vs 7.4 ± 3.1 cm; P = 0.02), matching closely historical normative post-mortem data. The mean and standard deviation of appendiceal length at CT were significantly greater among negative controls than in the positive appendicitis group (7.9 ± 3.5 vs 6.8 ± 1.9 cm; P = 0.03). Of appendicitis cases, 90 % (288/321) fell within the range 4.0-10.0 cm, compared with 59 % (189/321) of negative controls (P < 0.001). Among controls, a fivefold increase in appendixes >10 cm and a twofold increase in appendixes <4 cm were observed. Half (9/18) of long appendicitis cases showed tip appendicitis at CT.

CONCLUSIONS

"Intermediate" appendiceal lengths (4-10 cm) are more frequently complicated by acute appendicitis, whereas both "long" (>10 cm) and "short" (<4 cm) lengths are more frequently observed in unaffected adults.

Integrating MR imaging into the clinical workup of pregnant patients suspected of having appendicitis is associated with a lower negative laparotomy rate: single-institution study

PURPOSE

To determine if integrating magnetic resonance (MR) imaging into the workup of right lower quadrant pain in pregnant patients was associated with improved outcomes as measured by the negative laparotomy rate (NLR) and the perforation rate (PR).

MATERIALS AND METHODS

Institutional review board approval was obtained for this retrospective review of medical records. Two hundred sixty-seven pregnant patients who underwent either surgery (n = 82) or an MR imaging examination (n = 217) because of suspicion of appendicitis between January 1, 1996, and August 31, 2011, were identified. Relevant ultrasonographic and MR imaging reports were classified as showing true-positive, false-positive, true-negative, false-negative, or equivocal findings. MR imaging utilization was analyzed to define pre- and post-MR imaging cohorts. NLR and PR were calculated for both cohorts and were compared by using a Fisher exact probability test. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for MR imaging were calculated.

RESULTS

MR imaging was introduced into the clinical workup in 2004. From 1996 to 2003, the NLR for pregnant patients was 55% (17 of 31), and the PR was 21% (three of 14). From 2004 to 2011, the NLR was 29% (15 of 51), and the PR was 26% (nine of 35). The 47% decline in the NLR ([55%-29%]/55%) was statistically significant (P = .02). The change in PR was not significant (P > .99). The sensitivity, specificity, PPV, and NPV of MR imaging in the diagnosis of appendicitis were 89% (17 of 19), 97% (187 of 193), 74% (17 of 23), and 99% (187 of 189), respectively.

CONCLUSION

The routine incorporation of MR imaging into the clinical workup for suspicion of appendicitis in pregnant patients at this institution was associated with a decrease in the NLR of 47% without a significant change in the PR.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12121027/-/DC1.

[Ultrasound and CT scan in retrocecal appendicitis]

Le but de cette étude était de déterminer entre l'échographie et la tomodensitométrie, le moyen d'imagerie le plus approprié dans le diagnostic des appendicites retrocoecales. Il s'agissait d'une étude rétrospective ayant concerné les dossiers des patients qui ont bénéficié d'une échographie et d'une tomodensitométrie pour un syndrome appendiculaire. Nous avons retenu les dossiers des patients chez lesquels le diagnostic d'appendicite aigu a été posé par l'un des deux moyens d'imagerie, et confirmé par l'intervention chirurgicale. pendant 1 an, 19 cas d'appendicites retroceacales aiguës ont été retrouvées. L'âge moyen des patients était de 36 ans, avec une prédominance masculine. Les manifestations cliniques étaient dominées par la douleur dans l'hémi abdomen droit. La fièvre était présente dans tous les cas. On notait également une hyperleucocytose, et une élévation de la CRP chez tous les patients. L'échographie était normale dans 6 cas (32%), alors qu'elle mettait en évidence une infiltration de la paroi caecale, avec infiltration de la graisse péri caecale dans 13 cas (68%). La TDM abdominopelvienne a mis en évidence dans tous les cas, un appendice retrocaecale, épaissi avec un diamètre supérieur à 7 mm, et une infiltration de la graisse péri appendiculaire. La chirurgie avait confirmé le diagnostic d'appendicite retrocaecale. Les suites opératoires étaient satisfaisantes, sans complications. Le diagnostic d'une appendicite retrocaecale n'est pas aisé. L'échographie est le plus souvent non concluente. La TDM apparait comme le moyen d'imagerie de choix dans le diagnostic des appendicites retrocaecales.

Transabdominal ultrasound for bowel evaluation

This article considers the case for a strategic place for ultrasound (US) bowel evaluation focusing on three common clinical contexts. These include imaging for suspected acute appendicitis and acute diverticulitis, as well as the role of US in a multimodality approach for the diagnosis and management of inflammatory bowel disease and associated complications.

Reevaluating the sonographic criteria for acute appendicitis in children: a review of the literature and a retrospective analysis of 246 cases

RATIONALE AND OBJECTIVES

There has been little rigorous evaluation of the sonographic criteria for acute appendicitis in children. Our clinical experience has called the traditional diagnostic criteria into question. We set out to review the literature, evaluate the most commonly applied diagnostic criteria for acute appendicitis, and identify those criteria that best predict the presence of disease.

MATERIALS AND METHODS

A critical review of the literature concerning the sonographic diagnosis of acute appendicitis was performed. Based on diagnostic criteria identified in that review, two independent, blinded pediatric radiologists retrospectively reviewed 246 right lower quadrant ultrasound examinations in which the appendix was identified with attention to commonly described diagnostic criteria for acute appendicitis. Multivariate and classification and regression tree analysis were performed to identify criteria that predict appendicitis.

RESULTS

In a multivariate analysis, inflammation of the periappendiceal fat is the only finding that statistically significantly predicts acute appendicitis (OR = 68.93, P < .0001). Other criteria such as diameter, noncompressibility, hyperemia, the presence of an appendicolith, and loss of stratification of the appendiceal wall do not independently predict appendicitis.

CONCLUSION

Periappendiceal fat infiltration is the most important diagnostic criterion for acute appendicitis in children. Strict application of other criteria such as diameter should be avoided.

Sonography for appendicitis: nonvisualization of the appendix is an indication for active clinical observation rather than direct referral for computed tomography

PURPOSE

To determine the prevalence of perforated and nonperforated appendicitis in patients with nonvisualization of the appendix on ultrasound (US) performed for suspected appendicitis, and to evaluate the value of CT in these patients.

METHODS

We analyzed 400 consecutive patients undergoing US for suspected appendicitis. Of these patients, 260 had nonvisualization of the appendix, but otherwise normal scans. We analyzed the clinical outcome in these patients to determine the prevalence of appendicitis, referrals for CT, and the contribution of CT in these patients.

RESULTS

Of the 400 patients, 140 (35%) had either a normal (80 patients, 25%) or an abnormal appendix (60 patients, 15%); 260 (65%) had nonvisualization of the appendix. Overall 75 patients had appendicitis (18.8%) and 17 (4.3%) had appendicitis with perforation. Of the 260 patients with nonvisualization of the appendix, 14 patients (5.4%) had appendicitis and 2 were perforated (0.8%). The prevalence of perforated and nonperforated appendicitis in this group was significantly lower than the overall group (p < 0.001 and p < 0.01, respectively). Of these 260 patients, 101 patients (38.8%) had CT within 48 hours and 79 (78.2%) had normal scans.

CONCLUSIONS

Patients with nonvisualization of the appendix on US, but otherwise normal scans, are at significantly lower risk for appendicitis, either perforated or nonperforated. Active clinical observation should be considered in these patients, rather than direct referral for CT.

Ultrasonography aids decision-making in children with abdominal pain

INTRODUCTION

Although regular clinical assessment of the acute abdomen is considered best practice, ultrasonography confirming the presence of appendicitis will add to the decision-making process. The aim of this study was to assess the accuracy of ultrasonography and its usefulness in diagnosing acute appendicitis in a regional paediatric surgical institution.

METHODS

Retrospectively and in this order, radiology, theatre and histopathology databases were searched for patients who had presented with acute abdominal pain, patients who had undergone an appendicectomy and all appendix specimens over a two-year period. The databases were cross-referenced against each other.

RESULTS

A total of 273 non-incidental appendicectomies were performed over the study period. The negative appendicectomy rate was 16.5% and the perforation rate 23.7%. Thirty-nine per cent of children undergoing an appendicectomy had at least one pre-operative ultrasound scan. Ultrasonography as a diagnostic tool for acute appendicitis in children had a sensitivity of 83.3%, a specificity of 97.4%, a positive predictive value of 92.1% and a negative predictive value of 94.0%.

CONCLUSIONS

Ultrasonography is used liberally to aid in the decision making process of equivocal and complicated cases of acute appendicitis and it achieves good measures of accuracy. As a diagnostic tool it is unique in its ability to positively predict as well as exclude. A high negative predictive value suggests that more patients could be managed on an outpatient basis following a negative scan.

Use of antibiotics alone for treatment of uncomplicated acute appendicitis: a systematic review and meta-analysis

BACKGROUND

The use of antibiotics alone in the treatment of uncomplicated acute appendicitis has been controversial. The present report is based on a systematic review and meta-analysis of existing studies that compared antibiotics treatment to appendectomy in patients with uncomplicated acute appendicitis.

METHODS

A Medline search was performed for studies published between 1970 and 2009. Studies were selected based on specific inclusion and exclusion criteria. Six reports comprised of 1,201 patients were analyzed.

RESULTS

In patients treated with antibiotics alone, 6.9 ± 4.4% failed to respond and required appendectomy, and acute appendicitis recurred in 14.2 ± 10.6%. One appendectomy patient had a recurrence. A normal appendix was found in 7.3 ± 5.1% of patients at appendectomy. Complications were considerably less likely to occur with antibiotic treatment than with appendectomy. Major surgical complications included enterocutaneous fistula and reoperation.

CONCLUSION

In some cases, antibiotic treatment may fail, and there is a risk of recurrence. However, surgically treated patients, including those with the potential for spontaneous resolution and those with a normal appendix, are subjected to the risks of operative morbidity and mortality. Antibiotic therapy incurs significantly fewer complications. Prospective randomized studies are urgently needed to conclusively define the roles of appendectomy and antibiotic treatment in the management of uncomplicated acute appendicitis.

Revised ultrasound criteria for appendicitis in children improve diagnostic accuracy

BACKGROUND

Use of CT in the evaluation of suspected appendicitis in children is common. Expanding the use of US would eliminate the radiation exposure associated with CT.

OBJECTIVE

We describe new criteria that improve US's diagnostic accuracy for appendicitis, making it more comparable to CT in terms of sensitivity and specificity.

MATERIALS AND METHODS

We conducted a retrospective review of 304 consecutive patients undergoing US for the diagnosis of appendicitis in our institution during 2006. The sensitivity, specificity and accuracy of the maximal outer diameter (MOD) at various measurements was calculated and compared to pathology results. Additional variables (appendiceal wall thickness, fecalith, hyperemia, fat stranding, free fluid, age and weight) were also evaluated.

RESULTS

The highest sensitivity (98.7%) and specificity (95.4%) were identified when MOD was ≥7 mm or wall thickness was >1.7 mm. These values resulted in correctly classifying 96.6% of cases, with 1 (0.5%) false-negative and 6 (2.9%) false-positive studies. Incorporating secondary signs of appendicitis, age or weight did not alter accuracy.

CONCLUSION

These findings identify new US criteria that compare favorably to CT. In children with suspected appendicitis, using US as the initial imaging study will ultimately lead to improved accuracy, lower cost and the elimination of ionizing radiation exposure.

Ultrasonography aids decision-making in children with abdominal pain

INTRODUCTION

Although regular clinical assessment of the acute abdomen is considered best practice, ultrasonography confirming the presence of appendicitis will add to the decision-making process. The aim of this study was to assess the accuracy of ultrasonography and its usefulness in diagnosing acute appendicitis in a regional paediatric surgical institution.

METHODS

Retrospectively and in this order, radiology, theatre and histopathology databases were searched for patients who had presented with acute abdominal pain, patients who had undergone an appendicectomy and all appendix specimens over a two-year period. The databases were cross-referenced against each other.

RESULTS

A total of 273 non-incidental appendicectomies were performed over the study period. The negative appendicectomy rate was 16.5% and the perforation rate 23.7%. Thirty-nine per cent of children undergoing an appendicectomy had at least one pre-operative ultrasound scan. Ultrasonography as a diagnostic tool for acute appendicitis in children had a sensitivity of 83.3%, a specificity of 97.4%, a positive predictive value of 92.1% and a negative predictive value of 94.0%.

CONCLUSIONS

Ultrasonography is used liberally to aid in the decision making process of equivocal and complicated cases of acute appendicitis and it achieves good measures of accuracy. As a diagnostic tool it is unique in its ability to positively predict as well as exclude. A high negative predictive value suggests that more patients could be managed on an outpatient basis following a negative scan.

Sonographic appearance of the normal appendix in children

PURPOSE

To determine the visualization rate of the appendix in children without appendicitis and investigate factors affecting it.

METHODS

Between January 2010 and April 2010, 205 consecutive children (103 boys and 102 girls; mean age: 9 years) without clinical signs of appendicitis were examined by ultrasound (US). The location of appendix was determined. The outer appendiceal diameter with and without compression was measured and the content of the lumen and mural vascularity on color Doppler was determined. The appendix diameter was correlated with age, weight, and height using Pearson correlation. For age, weight, and height, children with a visualized appendix were compared with those in whom the appendix was not visualized using Student's t test.

RESULTS

The appendix was visualized in 142 of 205 (69.3%) children. The mean diameters of the appendices without and with compression were 4.2 ± 0.9 mm and 3.5 ± 0.8 mm, respectively, with 53.5% of the appendices in the mid-pelvic location. Appendiceal lumen was empty in 35.2% of children. Only one appendix showed mural vascularity on color Doppler. There was no correlation between the diameter (compressed or noncompressed) of the appendix and age, weight, or height. Mean ± SD age, weight, and height of the children with a visualized appendix (8.6 ± 0.3 years, 29.9 ± 0.9 kg, 127.7 ± 1.7 cm, respectively) were significantly lower than those in children with a nonvisualized appendix (9.8 ± 0.4 years, 36.0 ± 1.8 kg, 134.7 ± 2.5 cm, respectively) (p < 0.05 for all three parameters).

CONCLUSION

In the majority of the children, the appendix can be visualized with US. Age, weight, and height affect the visualization rate of the normal appendix.

Typical signs of acute appendicitis in ultrasonography mimicked by other diseases?

BACKGROUND

The diagnosis of acute appendicitis in pediatric patients is difficult. There are patients with positive ultrasonography without clinical or histological confirmation of acute appendicitis. It is essential to recognise these patients to avoid unnecessary surgery.

METHODS

During 1 year, we compared the patients with 'false-positive' ultrasonography with those with 'true-positive' and those with 'true-negative' ultrasonography.

RESULTS

Eighty-two patients were admitted to our inpatient ward for suspected appendicitis. Ultrasonography was performed on 68 patients. In sixteen cases, the ultrasonography showed typical signs of acute appendicitis though the patients turned out to be negative for acute appendicitis either by an observation period (n = 13) or by negative histology (n = 3). We could not find any significant differences between the groups in terms of age, gender or laboratory inflammation markers, though the latter tended to be elevated in patients with confirmed appendicitis.

CONCLUSIONS

There are patients with clearly visible typical signs of acute appendicitis that do not need surgery and cannot be distinguished from others by age, gender or laboratory values. In conclusion, the clinical presentation still is the determining indicator for need of surgery. The underlying cause of the visible changes of the appendiceal area remains unclear, but there are several presumptions.

[Modern sonography in the diagnosis of acute abdomen]

Acute abdomen is a serious clinical situation and prompt imaging is mandatory so that appropriate therapeutic measures can be taken. Multiple diseases can present with the clinical signs and symptoms of acute abdomen. Ultrasound is widely available and can be performed expeditiously. Recently, major technical innovations in ultrasound technology were introduced which greatly enhanced the diagnostic accuracy in the evaluation of acute abdomen. Contrast-enhanced ultrasound is among these valuable innovations. In this article the application of modern ultrasound techniques for the diagnosis of the most common causes of acute abdomen is outlined, which may be due to diseases of the gastro-intestinal tract, parenchymal organs in the upper abdomen as well as vascular disorders. Moreover, the diagnostic efficacy and the value as compared to other imaging modalities are analyzed.

Real-time elastography in acute appendicitis

OBJECTIVE

This study was done to evaluate the role of real-time Elastography (ES) in the diagnosis and staging the severity of acute appendicitis.

METHODS

Forty patients with acute pain in the right iliac fossa were evaluated using ES and sonography. All patients with a diagnosis of acute appendicitis on ES were also staged for the severity of appendicular inflammation and later underwent surgery, and the findings on imaging were confirmed and results compared. The sensitivity and specificity for ES and sonography were then calculated.

RESULTS

Elastography had sensitivity and specificity of 100% each, whereas sonography had sensitivity of 88% and specificity of 100%. Elastography also depicted the severity of inflammation, with 12 patients having mild, 8 having moderate, and 5 having severe appendicitis.

CONCLUSIONS

Combining ES with sonography improves the sensitivity in detection of acute appendicitis and can also be used to triage the severity of inflammation in such patients.

Evidence-based appendicitis: the initial work-up

In this article we provide an evidence-based review of appendicitis, which is one of the most challenging conditions to diagnose in patients presenting with abdominal pain. Almost all clinicians are faced with the diagnostic work-up of these patients, and missing the diagnosis can result in patient decompensation. We review the literature from the initial description of McBurney's point to the clinical presentation, as well as the most appropriate imaging testing. Additionally, we review the usefulness of specific diagnostic laboratory tests. The use of computed tomography scans has reduced negative appendectomy rates when combined with a physical examination, and assists in ruling out appendicitis. Computed tomography scans with no contrast or just rectal contrast are becoming the standard in many institutions. It is essential that when the diagnosis of abdominal pain of unclear etiology is suspected, the clinician's discussion with the patient is well documented on the patient's chart.

[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.

The equivocal appendix at CT: prevalence in a control population

The purpose of the study was to determine the prevalence of appendices with an equivocal appearance at computed tomography (CT) in a control population. We retrospectively identified a control population of 150 patients who underwent CT of the abdomen and pelvis for evaluation of hematuria (without abdominal pain, fever, or colonic disease). One reader measured the diameter of the appendix and noted if the appendix was either isodense in appearance or airless and fluid filled. Sixty-seven of 150 cases (44.6%) demonstrated appendiceal diameter greater than 6 mm. The appendix was collapsed or isodense in 34/150 cases (22.7%). Only ten of 150 or 6.6% of cases were isodense in combination with diameter greater than 6 mm, and none had diameter greater than 10 mm. Only one of 150 cases (0.67%) demonstrated airless fluid within the lumen, and the appendix measured less than 6 mm. While the diameter of the normal appendix is frequently greater than 6 mm, none measured greater than 10 mm in combination with ambiguous morphology. Furthermore, in the normal appendix, airless fluid filling the lumen is a rare appearance with a prevalence of less than 1%. While appendicitis could undoubtedly occur in an isodense appendix between 6 and 10 mm in diameter, such an appearance can occur in up to 6.6% of the normal population

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.

Pregnant patients suspected of having acute appendicitis: effect of MR imaging on negative laparotomy rate and appendiceal perforation rate

PURPOSE

To investigate the effect of magnetic resonance (MR) imaging on the negative laparotomy rate (NLR) and the perforation rate (PR) in pregnant patients suspected of having acute appendicitis (AA) and to assess the need for computed tomography (CT) in this setting.

MATERIALS AND METHODS

The data of 148 consecutive pregnant patients (mean age, 29 years; age range, 15-42 years; mean gestational age, 20 weeks; gestational age range, 4-37 weeks) who were clinically suspected of having AA and examined with MR imaging between March 2002 and August 2007 were retrospectively analyzed in an institutional review board-approved HIPAA-compliant protocol. One hundred forty patients underwent ultrasonography (US) before MR imaging. The clinical and laboratory data and the findings of the initial US and MR image interpretations were recorded and analyzed at Student t and Fisher exact testing. The NLR and PR were calculated.

RESULTS

Fourteen (10%) patients had AA, and perforation occurred in three (21%) of them. US results were positive for AA in five (36%) patients with proved AA. MR results were positive in all 14 patients with AA. MR results were negative in 125 of the 134 patients without AA; there were nine false-positive cases (two positive, seven inconclusive). Among the patients without AA, the normal appendix could be visualized on US images in less than 2% (two of 126) of cases and on MR images in 87% (116 of 134) of cases (P < .0001). Twenty-seven (18%) patients underwent surgical exploration, and eight of them had negative laparotomy results, yielding an NLR of 30% and a PR of 21% (three of 14 patients). Only four (3%) patients underwent CT.

CONCLUSION

For pregnant patients clinically suspected of having AA, use of MR imaging yields favorable combinations of NLR and PR compared with previously reported values. The radiation exposure associated with CT examination can be avoided in most cases.

Transabdominal sonography in assessment of the bowel in adults

OBJECTIVE

We describe the key sonographic features and technical aspects of assessment of bowel disorders in adults.

CONCLUSION

Initial imaging with transabdominal sonography in the radiologic evaluation of bowel disease in adults often is reserved for patients with equivocal historical, physical, and laboratory findings related to the gastrointestinal tract. Because of technologic advances and accumulated experience in interpretation of the images, sonography yields substantial information about gastrointestinal disorders.

Surgery for appendicitis: is it necessary?

BACKGROUND

Appendectomy for acute appendicitis is an effective, universally accepted procedure performed more than 300,000 times annually in the United States. It is generally believed that appendicitis progresses invariably from early inflammation to later gangrene and perforation, and that appendectomy is required for surgical source control. Although non-operative management with antibiotics of uncomplicated diverticulitis, salpingitis, and neonatal enterocolitis is now established, the non-operative management of appendicitis remains largely unexplored.

METHODS

Systematic review of published literature and derived expert opinion.

RESULTS

Clinical, epidemiologic, radiologic, and pathologic evidence is presented for spontaneous resolution of uncomplicated acute appendicitis. The pathogenesis of appendicitis is reviewed with specific consideration of the role of bacterial infection in the pathogenesis. Evidence is also provided documenting the clinical success of non-operative management.

CONCLUSIONS

Appendectomy may not be necessary for the majority of patients with acute uncomplicated appendicitis, as many patients resolve spontaneously and others may be treatable with antibiotics alone. However, the supporting documentation is scant and of poor quality. A randomized, prospective trial of non-operative management versus early appendectomy of acute uncomplicated appendicitis corroborated by radiologic imaging is called for.

Artificial neural networks: useful aid in diagnosing acute appendicitis

BACKGROUND

[corrected] The purpose of the study was to assess the role of artificial neural networks (ANNs) in the diagnosis of appendicitis in patients presenting with acute right iliac fossa (RIF) pain and comparing its performance with the assessment made by experienced clinicians and the Alvarado score.

METHODS

After training and testing an ANN, data from 60 patients presenting with suspected appendicitis over a 6-month period to a teaching hospital was collected prospectively. Accuracy of diagnosing appendicitis by the clinician, the Alvarado score, and the ANN was compared.

RESULTS

The sensitivity, specificity, and positive and negative predictive values of the ANN were 100%, 97.2%, 96.0%, and 100% respectively. The ability of the ANN to exclude accurately the diagnosis of appendicitis in patients without true appendicitis was statistically significant compared to the clinical performance (p=0.031) and Alvarado score of >or=6 (p=0.004) and nearly significant compared to the Alvarado score of >or=7 (p=0.063).

CONCLUSIONS

ANNs can be an effective tool for accurately diagnosing appendicitis and may reduce unnecessary appendectomies.

CT scan in patients with suspected appendicitis: clinical implications for the acute care surgeon

OBJECTIVE

To determine the influence of computed tomography (CT) scans on diagnosis and management of patients with suspected appendicitis.

METHODS

Retrospective 2-year review of 1,630 patients with suspected appendicitis, categorized into three groups based on the likelihood (Alvarado scores) of having appendicitis. Group 1: low likelihood (Alvarado score < or =4); group 2: intermediate likelihood (Alvarado scores 5-7), and group 3: high likelihood (Alvarado score > or = 8). CT scan utilization, hospital course, and final pathology were retrospectively reviewed.

RESULTS

More patients received a CT scan in 2006 as compared with 2005 (60 vs. 52%; p = 0.001). The overall appendectomy rate was similar between the 2 years (57% in 2005 vs. 57% in 2006; p = 0.995). The overall appendectomy rate in patients with a CT was significantly higher as compared with those without (60 vs. 53%; p = 0.002). The appendectomy rate in patients with Alvarado scores < or =4 and no CT scan was significantly lower than in those with a CT scan (12 vs. 48%; p < 0.0001). The overall negative appendectomy rate in patients with a CT scan was similar to that in those without: 31/546 (6%) vs. 23/383 (6%).

CONCLUSIONS

CT scan utilization increased the appendectomy rate only in patients with a low clinical suspicion for appendicitis. Preoperative CT scans did not decrease the negative appendectomy rate.

Integrated clinical-ultrasonographic diagnosis in acute appendicitis

PURPOSE

Acute appendicitis is one of the commonest diseases encountered in the field of emergency surgery. If untreated, it can rapidly develop severe complications such as perforation and peritonitis. Surgeons therefore often choose early surgical treatment also when the diagnosis is only probable, facing the risk of performing an elevated amount of unnecessary appendectomies. The aim of this study is to analyse our experience with integrated clinical-ultrasonographic diagnosis in acute appendicitis.

MATERIAL AND METHODS

From January 1999 to December 2006, 1447 patients underwent clinical examination, leucocyte count, evaluation of C-reactive protein level, and abdominal ultrasonography using graded compression technique and a high frequency probe.

RESULTS

In 368 patients (25%) ultrasonographic diagnosis was acute appendicitis; 8 patients were operated on the basis of clinical evaluation only. Ultrasonography yielded false positive results in 7 cases. In 1079 patients (75%) diagnosis was negative for acute appendicitis; 173 of these patients (12%) received a different diagnosis. The remaining 906 patients underwent clinical follow-up until the symptoms disappeared; there were no complications. In our study, sensitivity of ultrasonography was 98%, specificity 99%, positive predictive value 98%, and negative predictive value 99%. Overall diagnostic accuracy was 99%.

CONCLUSION

Integrated diagnosis of acute appendicitis based on clinical evaluation, laboratory tests and ultrasonography is safe and saves resources by preventing unnecessary operations.

Evaluation of negative appendicectomy rate in cases of suspected acute appendicitis and to study the usefulness of ultrasonography in improving the diagnostic accuracy

CONTEXT

Acute appendicitis poses a significant diagnostic challenge to the surgeon. Despite modern advances, the diagnosis of appendicitis remains essentially clinical. Ultrasonography is effective in supplementing the clinical diagnosis.

AIMS

This study aims to evaluate the negative appendicectomy rate in patients subjected to appendicectomy and to assess the usefulness of ultrasound in improving the diagnostic accuracy.

SETTINGS AND DESIGN

It is a retrospective review of prospectively collected data on 118 patients operated for suspected acute appendicitis in a single surgical unit between May 2001 and December 2002.

METHODS AND MATERIAL

The detailed history, clinical examination and preoperative investigations according to protocol were recorded on a proforma. All patients underwent an ultrasonography of whole abdomen including pelvis. Each patient with suspected acute appendicitis was subjected to surgery and appendix was submitted for histopathological examination. The negative rate of appendicectomy, sensitivity and specificity of ultrasonography and positive and negative predictive value of ultrasound were calculated.

RESULTS

The negative appendicectomy rate was 23.72%. In males it was 13.43% and in females 37.25%. Ultrasonography had a sensitivity of 63.33 % and a specificity of 82.14 %. The predictive value of a positive test was 91.93% and the predictive value of a negative test was 41.07%.

CONCLUSIONS

The clinical diagnosis of acute appendicitis when supplemented with an ultrasonography, can achieve a reasonable degree of diagnostic accuracy with resultant low negative exploration rates thereby reducing the financial burden and morbidity by avoiding unnecessary appendicectomy and keeping the cost of treatment affordable.

Ultrasonographic findings identifying the faecal-impacted appendix: differential findings with acute appendicitis

The aim of this study was to identify ultrasonographic findings that show the normal faecal-impacted appendix, in order to avoid unnecessary surgery via a misdiagnosis of acute appendicitis. Of 160 patients who underwent ultrasonography between January 2004 and July 2005 for right lower quadrant pain, 22 cases (including 7 cases confirmed pathologically and 15 confirmed clinically and on follow-up ultrasonography) were diagnosed as a normal faecal-impacted appendix. The criteria that we used to distinguish a faecal-impacted appendix from acute appendicitis include preservation of the normal wall layering of the appendix, maximum mural thickness, presence of peri-appendiceal fat infiltration and increased blood flow in the appendiceal wall. The maximum measured outer diameter of a normal faecal-impacted appendix was 0.54-1.03 cm, with a mean diameter of 0.68 cm. The maximum mural thickness ranged from 0.08 cm to 0.26 cm, with a mean thickness of 0.15 cm. The normal wall layers of the appendix were preserved and no evidence was seen of peri-appendiceal fat infiltration in any case. No demonstrably increased blood flow in the appendiceal wall was observed. In conclusion, faecal impaction increases the outer transverse diameter of the normal appendix, frequently leading to a misdiagnosis of acute appendicitis. Recognition of preservation of the normal layering of the appendiceal wall, smaller maximal outer diameter, thinner maximal mural thickness, the absence of peri-appendiceal mesenteric infiltration and no demonstrably increased blood flow in the appendiceal wall should help to prevent unnecessary surgery.

The impact of ultrasound in suspected acute appendicitis

AIMS

To evaluate prospectively the impact of an appendix ultrasound (US) service on the clinical management of patients presenting with suspected acute appendicitis.

MATERIALS AND METHODS

The referring clinician completed a proforma for patients presenting with suspected acute appendicitis. Two visual analogue scales assessed clinical suspicion before and after knowledge of laboratory results. The clinician also indicated if they intended to operate had US been unavailable. During a 3-year period, 327 patients were examined by graded-compression US and diagnosed "positive" or "negative" for acute appendicitis. Findings were correlated with histopathology results. The referring clinician completed a retrospective audit questionnaire to assess user satisfaction.

RESULTS

Clinical suspicion was altered by knowledge of laboratory results. The decision to operate if US had been unavailable, was "yes" in 70 cases (group A), "no" in 231 (group B), and incomplete in 26 (group C). In group A, 31 patients (44.3%) had a negative US and 25 avoided surgery. US identified 39 cases of appendicitis and 37 appendicectomies confirmed appendicitis in 34 cases. In group B, 72 (31.2%) patients had a positive US and 66 appendicectomies confirmed 51 cases of appendicitis. The sensitivity of US was 94.7% in group A, 93.3% in group B and 93.8% overall. Specificity was 90.6% in group A, 91.2% in group B and 91.3% overall. US findings were contrary to intended surgical management in 103 cases. Management was altered in 97 cases (32.2%), with a positive outcome in 85 (28.2%). The referrers found US of appendix very useful in planning appropriate management.

CONCLUSION

US of the appendix increases diagnostic accuracy, alters management and is more sensitive and specific than clinical impression, either alone, or in conjunction with laboratory results.

Current Concepts in Imaging of Appendicitis

Appendicitis is the most common cause of acute abdominal pain requiring surgery. Early diagnosis is crucial to the success of therapy. CT and ultrasound are widely recognized as very useful in the timely diagnosis of appendicitis. MR imaging is emerging as an alternative to CT in pregnant patients and in patients who have an allergy to iodinated contrast material. This article reviews the current imaging methods and diagnostic features of appendicitis.

Quelle est l’épaisseur de l’appendice normal au scanner multibarrette ?

OBJECTIVE

To determine the wall thickness and external diameter values of the normal appendix on multidetector computed tomography (MDCT). Materials and methods. A senior radiologist with no knowledge of the patient's surgical history prospectively examined the abdominal-pelvic CT scans of 57 consecutive adult patients with no suspicion for appendicitis. Most of the patients (50/57) received an intravenous iodinated contrast material injection, but none had gastrointestinal studies. All slices (1 and 5 mm) and multiplanar reconstructions were analyzed on a treatment console. The external diameter of the appendix, the thickness of the two appendicular walls, and the presence or absence of intraluminal gas were noted.

RESULTS

The appendix was visualized in 82% of the cases (47/57). The mean external diameter was 6.7 mm+/-1.2 (range, 5.0-11.0 mm). The mean thickness of the two walls was 4.8 mm+/-1.0 (range, 2.6-6.4 mm). Intraluminal air was visualized in 87% of cases (41/47).

CONCLUSION

Contrary to external diameter, the normal thickness of the appendix's two walls does not go beyond the threshold of 6 mm and therefore seems to be a reliable measurement for identifying a normal appendix using MDCT.

Sonographic appearance of the normal appendix in adults

OBJECTIVE

To evaluate the sonographic visualization of the normal adult appendix, a large series of sonographic images from consecutive asymptomatic patients was analyzed.

METHODS

A total of 788 consecutive adult patients (402 male and 386 female; median age +/- SD, 51.1 +/- 17.2 years; range, 16-91 years) were examined by appendiceal transabdominal sonography with tissue harmonic imaging. The detection rate, outer appendiceal diameter, intraluminal content, and location of the appendix were estimated. The overall normal appendix was separated into appendix-visualized and appendix-not-visualized groups, which were then examined for the relationship with abdominal wall thickness, body mass index (in kilograms per square meter), age, and sex.

RESULTS

The normal appendix was detected in 388 (49.2%) of 788 patients. The outer appendiceal diameter +/- SD was 4.27 +/- 1.2 mm (range, 1.0-11.1 mm). In 291 (75%) of the 388 patients, appendices could be depicted in the intra-luminal gas during sonography. The location of the appendix was classified according to the appendiceal tip, which was found to be abdominal in 37 (9.5%), pelvic in 291 (75%), retrocecal in 23 (6.0%), and a midline extension in 37 (9.5%). In both body mass index and abdominal wall thickness, significant differences were found between appendix-visualized and appendix-not-visualized cases (P < .05). There was no significant difference in age (P = .37) or sex (P = .23) between appendix-visualized and appendix-not-visualized cases.

CONCLUSIONS

The results show that the normal adult appendix can be revealed by sonographic visualization in a large series of asymptomatic patients.

Optimizing US examination to detect the normal and abnormal appendix in children

BACKGROUND

US detection of a normal appendix can safely rule out appendicitis. However, there is a wide range of accuracy in detection of a normal appendix.

OBJECTIVE

To optimize US examination to detect the normal and the abnormal appendix according to the potential positions of the appendix.

MATERIALS AND METHODS

This prospective study included 107 children who underwent gray-scale US scanning. Noncompressive and compressive graded sonography was performed to detect normal and abnormal appendices according to their potential positions. The maximum transverse diameter of the appendices was measured.

RESULTS

Of the 107 children examined, 56 had a histologic diagnosis of acute appendicitis. Sonography had a sensitivity of 100% and specificity of 98% for the diagnosis of appendicitis. A normal appendix was visualized in 44 (86.2%) of the 51 patients without acute appendicitis, and of these 44, 43 were true-negative and 1 was false-positive. Normal and abnormal appendices, respectively, were positioned as follows: 54.4% and 39.3% were mid-pelvic; 27.2% and 28.6% were retrocecal; 11.4% and 17.8% were deep pelvic; and 6.8% and 14.3% were abdominal.

CONCLUSION

US scanning according to the potential positions of the appendix was useful in the detection of normal appendices in children suspected of having appendicitis.