Diagnostic accuracy of focused appendiceal CT in clinically equivocal cases of acute appendicitis

Computed Tomography for Acute Appendicitis Diagnosis and Confirmation in Men : Trends and Cost Implications

INTRODUCTION

The classic findings of acute appendicitis-right lower quadrant pain, anorexia, and leukocytosis-have been well known. However, emergency medicine and surgical providers continue to rely on imaging to confirm the diagnosis. We aimed to evaluate the increase in reliance on computed tomography (CT) scans for acute appendicitis diagnosis over time.

METHODS

We conducted a retrospective study of patients ≥18 years presenting to UNC Hospitals with signs and symptoms of acute appendicitis who subsequently underwent appendectomy from 2011 to 2015. Demographic, clinical, laboratory, and pathologic data were reviewed. We evaluated the incidence of CT scans stratified by year, age, and sex.

RESULTS

Within our male population, 55.2% (278/504) had classic appendicitis symptoms. Of the 278 male patients with classic appendicitis symptoms, 248 underwent CT imaging. Male patients <45 years of age were more likely to present with classic appendicitis symptoms (216/357, 60.5%) compared with patients aged 46-65 (52/108, 48.1%) or >65 (10/39, 25.6%). Of the male patients <45 years with classic appendicitis symptoms, the incidence of CT scans increased over time (68.3% in 2011, 84.2% in 2012, 92.3% in 2013, 93.9% in 2014, 92.3% in 2015). When considering the 216 CT scans that could have been avoided in our population, we calculate an approximate savings of $173 998.80 over 5 years.

CONCLUSION

The incidence of CT scans for acute appendicitis confirmation has increased over time even in men. CT scans for the diagnosis or confirmation of acute appendicitis should rarely be indicated in men aged <45 years with classic appendicitis symptoms.

Convolutional-neural-network-based diagnosis of appendicitis via CT scans in patients with acute abdominal pain presenting in the emergency department

Acute appendicitis is one of the most common causes of abdominal emergencies. We investigated the feasibility of a neural-network-based diagnosis algorithm of appendicitis by using computed tomography (CT) for patients with acute abdominal pain visiting the emergency room (ER). A neural-network-based diagnostic algorithm of appendicitis was developed and validated using CT data from three institutions who visited the ER with abdominal pain and underwent abdominopelvic CT. For input data, 3D isotropic cubes including the appendix were manually extracted and labeled as appendicitis or a normal appendix. A 3D convolutional neural network (CNN) was trained to binary classification on the input. For model development and testing, 8-fold cross validation was conducted for internal validation and an ensemble model was used for external validation. Diagnostic performance was excellent in both the internal and external validation with an accuracy larger than 90%. The CNN-based diagnosis algorithm may be feasible in diagnosing acute appendicitis using the CT data of patients visiting the ER with acute abdominal pain.

Computed tomography for diagnosis of acute appendicitis in adults

BACKGROUND

Diagnosing acute appendicitis (appendicitis) based on clinical evaluation, blood testing, and urinalysis can be difficult. Therefore, in persons with suspected appendicitis, abdominopelvic computed tomography (CT) is often used as an add-on test following the initial evaluation to reduce remaining diagnostic uncertainty. The aim of using CT is to assist the clinician in discriminating between persons who need surgery with appendicectomy and persons who do not.

OBJECTIVES

Primary objective Our primary objective was to evaluate the accuracy of CT for diagnosing appendicitis in adults with suspected appendicitis. Secondary objectives Our secondary objectives were to compare the accuracy of contrast-enhanced versus non-contrast-enhanced CT, to compare the accuracy of low-dose versus standard-dose CT, and to explore the influence of CT-scanner generation, radiologist experience, degree of clinical suspicion of appendicitis, and aspects of methodological quality on diagnostic accuracy.

SEARCH METHODS

We searched MEDLINE, Embase, and Science Citation Index until 16 June 2017. We also searched references lists. We did not exclude studies on the basis of language or publication status.

SELECTION CRITERIA

We included prospective studies that compared results of CT versus outcomes of a reference standard in adults (> 14 years of age) with suspected appendicitis. We excluded studies recruiting only pregnant women; studies in persons with abdominal pain at any location and with no particular suspicion of appendicitis; studies in which all participants had undergone ultrasonography (US) before CT and the decision to perform CT depended on the US outcome; studies using a case-control design; studies with fewer than 10 participants; and studies that did not report the numbers of true-positives, false-positives, false-negatives, and true-negatives. Two review authors independently screened and selected studies for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently collected the data from each study and evaluated methodological quality according to the Quality Assessment of Studies of Diagnostic Accuracy - Revised (QUADAS-2) tool. We used the bivariate random-effects model to obtain summary estimates of sensitivity and specificity.

MAIN RESULTS

We identified 64 studies including 71 separate study populations with a total of 10,280 participants (4583 with and 5697 without acute appendicitis). Estimates of sensitivity ranged from 0.72 to 1.0 and estimates of specificity ranged from 0.5 to 1.0 across the 71 study populations. Summary sensitivity was 0.95 (95% confidence interval (CI) 0.93 to 0.96), and summary specificity was 0.94 (95% CI 0.92 to 0.95). At the median prevalence of appendicitis (0.43), the probability of having appendicitis following a positive CT result was 0.92 (95% CI 0.90 to 0.94), and the probability of having appendicitis following a negative CT result was 0.04 (95% CI 0.03 to 0.05). In subgroup analyses according to contrast enhancement, summary sensitivity was higher for CT with intravenous contrast (0.96, 95% CI 0.92 to 0.98), CT with rectal contrast (0.97, 95% CI 0.93 to 0.99), and CT with intravenous and oral contrast enhancement (0.96, 95% CI 0.93 to 0.98) than for unenhanced CT (0.91, 95% CI 0.87 to 0.93). Summary sensitivity of CT with oral contrast enhancement (0.89, 95% CI 0.81 to 0.94) and unenhanced CT was similar. Results show practically no differences in summary specificity, which varied from 0.93 (95% CI 0.90 to 0.95) to 0.95 (95% CI 0.90 to 0.98) between subgroups. Summary sensitivity for low-dose CT (0.94, 95% 0.90 to 0.97) was similar to summary sensitivity for standard-dose or unspecified-dose CT (0.95, 95% 0.93 to 0.96); summary specificity did not differ between low-dose and standard-dose or unspecified-dose CT. No studies had high methodological quality as evaluated by the QUADAS-2 tool. Major methodological problems were poor reference standards and partial verification primarily due to inadequate and incomplete follow-up in persons who did not have surgery.

AUTHORS' CONCLUSIONS

The sensitivity and specificity of CT for diagnosing appendicitis in adults are high. Unenhanced standard-dose CT appears to have lower sensitivity than standard-dose CT with intravenous, rectal, or oral and intravenous contrast enhancement. Use of different types of contrast enhancement or no enhancement does not appear to affect specificity. Differences in sensitivity and specificity between low-dose and standard-dose CT appear to be negligible. The results of this review should be interpreted with caution for two reasons. First, these results are based on studies of low methodological quality. Second, the comparisons between types of contrast enhancement and radiation dose may be unreliable because they are based on indirect comparisons that may be confounded by other factors.

Focused CT for the evaluation of suspected appendicitis

PURPOSE

To determine the diagnostic accuracy of focused appendiceal CT as a feasible alternative to the standard CT of the abdomen and pelvis (CT-AP) in patients with suspected acute appendicitis.

METHODS

Retrospective review of 200 adults with suspected acute appendicitis between January and October 2016 were included in this study. Each patient underwent CT-AP with oral and intravenous (IV) contrast. A subset of axial images starting at the top of L4 vertebral body to the roof of the acetabula were obtained from each study which served as the focused appendiceal CT. After review of the focused CTs, the non-focused CT-AP scans were reviewed, each patient acting as their own control. Images were assessed for ability to identify the appendix, assess for appendicitis, or identify alternative diagnoses that could account for the presenting symptoms.

RESULTS

Of 200 cases, the appendix was visualized in the focused CT in 191 patients. In nine studies, the appendix was not visualized in focused or standard CT-AP. Using focused CT, 42 cases were positive for acute appendicitis. This result was identical when reviewing standard CT-AP. Alternative diagnoses were present in 38 patients. Using focused CT, 14 of these were not fully covered but the readers were able to make the diagnoses confidently on the focused CTs. Only one patient had acute non-appendiceal pathology mostly outside of the field of view.

CONCLUSIONS

Focused appendiceal CT with IV and oral contrast in the setting of clinically suspected appendicitis is a suitable alternative to conventional CT-AP.

Are Preoperative CT Findings Useful for Predicting Postoperative Intraabdominal Abscess in the Patients with Acute Appendicitis?

Background and objective: In patients with acute appendicitis (AA), preoperative computed tomography (CT) findings suggesting development of intraabdominal abscess (IAA) had not been widely used. The aim of this study was to investigate the preoperative clinical and radiological factors that predict the development of a postoperative IAA in patients with AA who were treated by laparoscopic appendectomy (LA). Methods: Two hundred and sixteen patients with pathologically proven AA underwent LA between January 2013 and March 2018 in our department. Medical records and preoperative CT images of these 216 patients were retrospectively reviewed and the predictive factors of postoperative IAA were investigated. In addition, patients were divided into complicated appendicitis (CA) and simple appendicitis (SA) and perioperative factors of two groups were compared. Results: One hundred and forty-seven patients were diagnosed with CA, while the other 69 patients were diagnosed with SA. Sixteen patients developed postoperative IAA in the CA group, while no patients in the SA group did. The univariate analysis revealed that time from onset to surgery more than 3 days (p = 0.011), the preoperative CT finding of periappendiceal fluid (p = 0.003), abscess (p < 0.001), and free air (p < 0.001), operation time more than 120 min (p = 0.023) and placement of a drainage tube (p < 0.001) were significantly associated with the development of IAA. Multivariate analysis revealed that the preoperative CT finding of free air was independently associated with the development of IAA (p = 0.007, odds ratio = 5.427, 95% CI: 1.586⁻18.57). Conclusions: IAA developed predominantly in patients with CA. Preoperative CT findings of free air was found to be an independent predictor for the development of IAA. Surgeons should be meticulous in managing the postoperative course of patients with this finding.

Management, treatment and outcomes of acute appendicitis in an elderly population: a single-center experience

INTRODUCTION

Only 5-10% of cases of acute appendicitis (AA) are diagnosed above the age of 60 years. Complicated AA is more common in the elderly, who also have more comorbidities. The goals of this study were to describe our experience with elderly patients and identify predictors of increased morbidity.

MATERIAL AND METHODS

Patients ≥65 years who were treated for AA between 2006 and 2013 were selected. The control consisted of patients aged 20-45 years, who were randomly selected from a pool of 900 patients.

RESULTS

Seventy-four patients ≥65 years, mean age of 74.6 ± 7.4, were included. Time from onset of symptoms to surgery was similar between the groups. CT scan was performed for all patients in the elderly group compared to 55.6% in the younger group (p < 0.001). 77% of the younger patients underwent laparoscopic appendectomy compared to 43.2% of the elderly patients (p < 0.001). Pathological findings of severe appendicitis were significantly more common in the elderly group (39.2 vs. 10.5%, p < 0.001). Sixteen elderly patients (21.6%) developed complications, compared with 4 patients (3.2%) in the younger group (p < 0.001). The length of stay was longer in the elderly group and even longer for patients with complications (p < 0.001). There was no mortality. Cardiac disease was the only independent predictor of peri-operative complications (OR = 4.2).

CONCLUSIONS

Severe forms of acute appendicitis and post-operative morbidity are higher in the elderly population. Cardiac disease is the only predictor for increased morbidity. Although CT scan was performed universally in the elderly group, it did not appear to increase time from presentation to surgery.

Intravenous and Oral Contrast vs Intravenous Contrast Alone Computed Tomography for the Visualization of Appendix and Diagnosis of Appendicitis in Adult Emergency Department Patients

Purpose

The study sought to compare radiologist's ability to 1) visualize the appendix; 2) diagnose acute appendicitis; and 3) diagnose alternative pathologies responsible for acute abdominal pain among adult patients undergoing computed tomography (CT) scan with 3 different protocols: 1) intravenous (IV) contrast only; 2) IV and oral contrast with 1-hour transit time; and 3) IV and oral contrast with 3-hour transit time.

Methods

We collected data of 225 patients; 75 consecutive patients with a clinical suspicion of appendicitis received oral contrast for 3 hours and IV contrast, 75 received oral contrast for 1 hour and IV contrast, and 75 trauma patients received IV contrast only. Three independent reviewers, blinded to final pathology, retrospectively analysed the cases and documented visualization of the appendix, periappendiceal structures, and their confidence in diagnosing appendicitis. Clinical diagnoses were derived from a combination of clinical, surgical, pathologic, or radiologic follow-up.

Results

Frequency of visualizing the appendix within IV group alone was 87.3%, IV with oral for 1 hour was 94.1%, and IV with oral for 3 hours was 93.8%. Both oral contrast groups had 100% sensitivity and negative predictive value in diagnosis of acute appendicitis. Specificity for the 1- and 3-hour oral contrast groups was 94.1% and 96.1%, respectively and positive predictive value for both groups was 92%.

Conclusions

Our findings suggest that reader confidence in visualizing the appendix improved with addition of oral contrast as compared to IV contrast alone. One- and 3-hour oral regimens have a similar diagnostic performance in diagnosing appendicitis.

Appendiceal location analysis and review of the misdiagnosis rate of appendicitis associated with deep pelvic cecum on multidetector computed tomography

OBJECTIVE

To investigate appendiceal location and misdiagnosis rate of appendicitis associated with deep pelvic cecum on multidetector computed tomography (MDCT).

MATERIALS AND METHODS

Among 1107 appendicitis cases, 25 patients with deep pelvic cecum and 75 patients with conventional cecum on MDCT were retrospectively selected for analysis of appendiceal locations and preoperative misdiagnosis rate.

RESULTS

The major appendiceal direction in deep pelvic cecum group was ascending (84.0%). The misdiagnosis rates of appendicitis in deep pelvic and conventional cecum groups were 16% and 5.3%.

CONCLUSION

A deep pelvic cecum may cause misdiagnosis of appendicitis. The appendix associated with deep pelvic cecum mainly demonstrates right ascending direction.

A Feasibility Study of Real-Time Remote CT Reading for Suspected Acute Appendicitis Using an iPhone

We aimed to evaluate the feasibility of an iPhone-based remote control system as a real-time remote computed tomography (CT) reading tool for suspected appendicitis using a third-generation (3G) network under suboptimal illumination. One hundred twenty abdominal CT scans were selected; 60 had no signs of appendicitis, whereas the remaining 60 had signs of appendicitis. The 16 raters reviewed the images using the liquid crystal display (LCD) monitor of a picture archiving and communication system (PACS) workstation, as well as using an iPhone connected to the PACS workstation via a remote control system. We graded the probability of the presence of acute appendicitis for each examination using a five-point Likert scale. The overall sensitivity and specificity for the diagnosis of suspected appendicitis using the iPhone and the LCD monitor were high, and they were not significantly different (sensitivity P = 1.00, specificity P = 0.14). The average areas under the receiver operating characteristic curves for all CT readings with the iPhone and LCD monitor were 0.978 (confidence interval 0.965-0.991) and 0.974 (0.960-0.988), respectively, and the two devices did not have significantly different diagnostic performances (P = 0.55). The inter-rater agreement for both devices was very good; the kappa value for the iPhone was 0.809 (0.793-0.826), and that for the LCD monitor was 0.817 (0.801-0.834). Each rater had moderate-to-very good intra-observer agreement between the two devices. We verified the feasibility of an iPhone-based remote control system as a real-time remote CT reading tool for identifying suspected appendicitis using a 3G network and suboptimal illumination.

Diagnostic Imaging of Appendicitis With Supplementation by Transabdominal and Transvaginal Sonography

Acute appendicitis is a condition that can affect any member of the population. Without timely treatment there is a high likelihood of rupture leading to peritonitis, and early diagnosis is imperative to obtaining treatment. Sonography can be used without fear of radiation exposure to the patient and with relatively little discomfort, ideal for pediatric patients. It can also be used with little patient preparation, with the possibility of a more rapid diagnosis than other imaging modalities. For patients presenting with atypical symptoms, sonography may be used to increase diagnostic accuracy, which will lead to a drop in the surgical removal rate of a healthy appendix. When diagnostic criteria are met, sonography results can be correlated with the patient’s blood test and clinical symptoms to make a positive diagnosis. The addition of the transvaginal approach for female patients has further increased the rate of success of diagnosing acute appendicitis, so that appropriate emergent surgery can be done.

Computed tomography: revolutionizing the practice of medicine for 40 years

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

The normal appendix on CT: does size matter?

PURPOSE

(1) To evaluate the frequency of visualisation and measurements of the normal appendix. (2) To correlate Body Mass Index (BMI) and gender with visualisation of the normal appendix. (3) To correlate age, gender and body length with appendiceal length.

MATERIALS AND METHODS

A retrospective review of 186 patients undergoing abdominal CT without suspicion of acute appendicitis was done. Frequency of visualisation and measurements (including maximal outer diameter, wall thickness, length, content, location of base and tip) of normal appendices were recorded.

RESULTS

Prevalence of appendectomy was 34.4%. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of visualisation of the normal appendix were 76%, 94%, 96%, 67%, and 82% respectively. The mean maximal diameter of the appendix was 8.19 mm±1.6 (SD) (range, 4.2-12.8 mm). The mean length of the appendix was 81.11 mm±28.44 (SD) (range, 7.2-158.8 mm). The mean wall thickness of the appendix was 2.22 mm±0.56 (SD) (range, 1.15-3.85 mm). The most common location of the appendiceal tip was pelvic in 66% appendices. The most common location of the appendiceal base was inferior, medial, and posterior in 37%. The normal appendix contained high-density material in 2.2%. There was a significant correlation between gender and appendiceal length, with men having longer appendices than women.

CONCLUSION

Most normal appendices are seen at multislice CT using i.v. contrast. The maximal outer diameter of the normal appendix overlaps with values currently used to diagnose appendicitis on CT.

Improvement in the diagnosis of appendicitis

Our attempts to systematically improve accuracy in the evaluation of patients with suspected appendicitis are, in some ways, hindered by the fact that the condition is so frequently straightforward to diagnose. Careful history-taking and physical examination are reliable in most patients. However, establishing the diagnosis with these skills alone remains vulnerable to conditions that masquerade as acute appendicitis. A substantial body of clinical research over the last quarter-century has shown that improved accuracy is possible. Strategies for improvement include the use of diagnostic scoring systems, laboratory makers such as CRP, diagnostic laparoscopy, and advanced imaging modalities such as CT, MRI, and US. How clinicians use these strategies depends on many factors related to practice setting, the population served, and clinical goals. In children, for instance, the desire to limit exposure to ionizing radiation competes with the greater anatomic detail that a CT scan can provide; at the same time, many hospitals that treat children do not have the resources to maintain the sort of full-time, highly sophisticated abdominal US programs that achieve the highest rates of diagnostic accuracy in clinical studies. Trade-offs have to be made, but improvement is possible in almost all groups of patients: the clinical community should no longer settle for a 15% NA rate when 5% is clearly possible without adverse consequences. Many clinicians will be faced with the task of evaluating patients suspected of having acute appendicitis. A deliberate, proactive, and, ideally, benchmarked strategy for improving diagnosis should be the standard to which we hold ourselves and the promise we deliver to our patients.

Optimised z-axis coverage at multidetector-row CT in adults suspected of acute appendicitis

OBJECTIVE

To compare diagnostic performances of two reduced z-axis coverages to full coverage of the abdomen and pelvis for the diagnosis of acute appendicitis and alternative diseases at unenhanced CT.

METHODS

This study included 152 adults suspected of appendicitis who were enrolled in two ethical committee-approved previous prospective trials. Based on scans covering the entire abdomen and pelvis (set L), two additional sets of images were generated, each with reduced z-axis coverages: (1) from the top of the iliac crests to the pubis (set S) and (2) from the diaphragmatic crus to the pubis (set M). Two readers independently coded the visualisation of the appendix, measured its diameter and proposed a diagnosis (appendicitis or alternative). Final diagnosis was based on surgical findings or clinical follow-up. Fisher exact and McNemar tests and logistic regression were used.

RESULTS

46 patients had a definite diagnosis of appendicitis and 53 of alternative diseases. The frequency of appendix visualisation was lower for set S than set L for both readers (89% and 84% vs 95% and 91% by Readers A and B, respectively; p=0.021 and 0.022). The probability of giving a correct diagnosis was lower for set S (68%) than set L (78%; odds ratio, 0.611; p=0.008) for both readers, without significant difference between sets L and M (77%, p=0.771); z-axis coverage being reduced by 25% for set M.

CONCLUSION

Coverage from diaphragmatic crus to pubis, but not focused on pelvis only, can be recommended in adults suspected of appendicitis.

ADVANCES IN KNOWLEDGE

In suspected appendicitis, CT-coverage can be reduced from diaphragmatic crus to pubis.

Intraluminal air within an obstructed appendix: a CT sign of perforated or necrotic appendicitis

RATIONALE AND OBJECTIVES

The aim of this study was to evaluate the predictive value of intraluminal air for appendiceal necrosis and/or perforation when not apparent on imaging. Additional factors of intraluminal appendicoliths, age, and gender were also assessed.

MATERIALS AND METHODS

Patients with pathologically proven appendicitis who underwent multidetector computed tomographic imaging over a 3-year period (n = 487) were retrospectively reviewed. Those with imaging evidence for perforation were excluded to create a study population of apparent uncomplicated acute appendicitis (n = 374). Each scan was assessed for intraluminal appendiceal air and appendicoliths on multidetector computed tomography and compared against surgical and pathologic results for appendiceal necrosis and/or perforation.

RESULTS

Image-occult necrosis or perforation was present in 17.4% (65 or 374) of the study cohort. Intraluminal air and appendicoliths were predictive variables by univariate logistic regression (P = .001 and P ≤ .001, respectively), with odds ratios of 2.64 (95% confidence interval, 1.48-4.73) for intraluminal air and 2.67 (95% confidence interval, 1.55-4.61) for appendicoliths. Both remained independent variables on multivariate modeling despite multicollinearity. Increasing age was also predictive (odds ratio, 1.25; 95% confidence interval, 1.09-1.44; P = .002), whereas gender was not (P = .472).

CONCLUSIONS

Intraluminal appendiceal air in the setting of acute appendicitis is a marker of perforated or necrotic appendicitis. Recognition of this finding in otherwise uncomplicated appendicitis at imaging should raise suspicion for image-occult perforation or necrosis.

Synchronous obstructive ureterolithiasis and acute appendicitis

The differential diagnosis of right lower quadrant abdominal pain includes both ureterolithiasis and acute appendicitis. Surgical treatment can be undergone without confirmatory imaging studies after a clinical diagnosis is made. For this reason, an occult, second abdominal process may be present.

A 47-year-old male presented with a three-day history of acute right lower quadrant abdominal pain. A contrast CT revealed both a 6 mm calculus obstructing the right ureter and acute appendicitis. The patient underwent appendectomy and ureteroscopy with stent placement at the same time.

Simultaneous appendicitis and ureterolithiasis may present with similar clinical findings. Due to the potential risks associated with missing either diagnosis, imaging studies may be an appropriate as a step in the management of the patient with right lower quadrant pain.

Visualization of the normal appendix with MR enterography in children

BACKGROUND

Magnetic resonance (MR) imaging may provide a radiation-sparing alternative to CT in diagnosing appendicitis in children in whom US is equivocal. However, comparability with CT in the detection of the appendix remains to be established.

OBJECTIVE

To determine the detection rate of the normal appendix in children on oral and IV contrast-enhanced MRI.

METHODS

MR imaging of 58 patients who had previously undergone MR enterography was retrospectively reviewed. Detection rate, body mass index, age and gender were recorded.

RESULTS

The normal appendix was detected in 28 cases (48%), with greatest detection rate on the axial fast imaging employing steady-state acquisition (FIESTA) sequence. Children in whom the appendix was detected had significantly higher BMI compared to children in whom the appendix was not seen. Neither age nor gender demonstrated a significant association with detection rate.

CONCLUSION

The detection rate of the normal appendix in children on oral and IV contrast-enhanced MRI was 48%, which is comparable to detection rates on CT, as well as to previously reported detection rates on MR imaging with neither oral nor IV contrast agents. These findings may serve to guide the development of MRI protocols for pediatric appendicitis.

Reassessment of CT images to improve diagnostic accuracy in patients with suspected acute appendicitis and an equivocal preoperative CT interpretation

OBJECTIVES

To identify CT features that discriminate individuals with and without acute appendicitis in patients with equivocal CT findings, and to assess whether knowledge of these findings improves diagnostic accuracy.

METHODS

53 patients that underwent appendectomy with an indeterminate preoperative CT interpretation were selected and allocated to an acute appendicitis group or a non-appendicitis group. The 53 CT examinations were reviewed by two radiologists in consensus to identify CT findings that could aid in the discrimination of those with and without appendicitis. In addition, two additional radiologists were then requested to evaluate independently the 53 CT examinations using a 4-point scale, both before and after being informed of the potentially discriminating criteria.

RESULTS

CT findings found to be significantly different in the two groups were; the presence of appendiceal wall enhancement, intraluminal air in appendix, a coexistent inflammatory lesion, and appendiceal wall thickening (P < 0.05). Areas under the curves of reviewers 1 and 2 significantly increased from 0.516 and 0.706 to 0.677 and 0.841, respectively, when reviewers were told which CT variables were significant (P = 0.0193 and P = 0.0397, respectively).

CONCLUSIONS

Knowledge of the identified CT findings was found to improve diagnostic accuracy for acute appendicitis in patients with equivocal CT findings.

KEY POINTS

• Numerous patients with clinically equivocal appendicitis do not have acute appendicitis • Computed tomography (CT) helps to reduce the negative appendectomy rate • CT is not always infallible and may also demonstrate indeterminate findings • However knowledge of significant CT variables can further reduce negative appendectomy rate • An equivocal CT interpretation of appendicitis should be reassessed with this knowledge.

Diagnostic Value of C-reactive Protein in Complicated Appendicitis

PURPOSE

Early detection of appendicitis has increased due to development of computed tomography and ultrasonography, yet we are frequently meeting complicated appendicitis, including perforation, abscess and a gangrenous appendicitis due to delayed diagnosis. For that reason, we want to evaluate predictive factors for the complicated appendicitis.

METHODS

A total of 128 patients with appendicitis, after 13 patients with a duration of under 12 hours and 15 patients with pathological non-appendicitis were excluded from 156 patients, who visited Kwangju Christian Hospital from November 2008 to November 2010 were retrospectively reviewed.

RESULTS

There were 62 patients (48.3%) with simple appendicitis and 66 patients (51.7%) with complicated appendicitis. In univariate analysis, age (P < 0.001), C-reactive protein (P < 0.001) and the diameter of the appendix (P = 0.006), were found to be significant. Multivariate analysis demonstrated that C-reactive protein was an independent predictor for complicated appendicitis (odds ratio, 1.371; 95% confidence interval, 1.155 to 1.628; P < 0.001). The cut-off value of C-reactive protein was set at 7.05 mg/dL by using receiver operating characteristic curve (0.805; sensitivity, 57.6%; specificity, 98.3%).

CONCLUSION

This study suggests that if C-reactive protein is above 7.05 mg/dL, immediate and proper management should be performed due to a high probability of complicated appendicitis, especially in young children or elderly patients who frequently present with vague symptoms.

Clinical policy: Critical issues in the evaluation and management of emergency department patients with suspected appendicitis

This clinical policy from the American College of Emergency Physicians is an update of a 2000 clinical policy on the evaluation and management of patients presenting with nontraumatic acute abdominal pain.1 A writing subcommittee reviewed the literature to derive evidence-based recommendations to help clinicians answer the following critical questions: (1)Can clinical findings be used to guide decision making in the risk stratification of patients with possible appendicitis? (2) In adult patients with suspected acute appendicitis who are undergoing a computed tomography scan, what is the role of contrast? (3) In children with suspected acute appendicitis who undergo diagnostic imaging, what are the roles of computed tomography and ultrasound in diagnosing acute appendicitis?Evidence was graded and recommendations were given based on the strength of the available data in the medical literature.

Atypical appendicitis: the impact of CT and its management

Acute appendicitis is a diagnosis that can be made on clinical symptoms and signs but can often be extremely challenging. Difficulties arise particularly when the presentation is atypical, and this can lead to untoward sequelae. In this review, we present the range of presentations of atypical appendicitis, the variety of management options and the potential value of CT.

Focused helical CT using rectal contrast material only as the preferred technique for the diagnosis of suspected acute appendicitis: a prospective, randomized, controlled study comparing three different techniques

PURPOSE

Focused helical CT using rectal contrast material only has emerged recently as an accurate diagnostic tool for the evaluation of suspected acute appendicitis. This study was designed to prospectively compare the efficacy of rectal contrast CT to other commonly used contrast-enhanced and nonenhanced CT techniques for the detection of acute appendicitis.

METHODS

A total of 232 patients with clinically suspected appendicitis were randomly assigned to one of three focused helical CT techniques: noncontrast enhanced CT, CT using rectal contrast material only, and dual-contrast CT using both oral and intravenous material. All scans were interpreted by the on-call residents and reported immediately to the surgeon. The sensitivity, specificity, predictive values, and overall accuracy rates were compared between the protocols.

RESULTS

One hundred eleven patients (48 percent) had acute appendicitis. The sensitivity and specificity rates of rectal contrast CT were 93 and 95 percent, respectively, with overall accuracy of 94 percent. The sensitivity and specificity rates of dual-contrast CT were 100 and 89 percent, respectively, with overall accuracy of 94 percent. The sensitivity and specificity of noncontrast enhanced CT were 90 and 86 percent, respectively, but the overall accuracy was significantly lower (70 percent) compared with the other studies.

CONCLUSIONS

Rectal contrast CT is as accurate, although less sensitive, compared with dual-contrast CT and significantly superior to noncontrast-enhanced CT for the diagnosis of acute appendicitis. Rectal contrast CT may be performed rapidly, saves resources, and may avoid the diagnostic delay and potential allergic reactions associated with oral and intravenous-enhanced studies, and, therefore, may be the preferred initial technique in the diagnostic workup of suspected acute appendicitis.

Pelvic inflammatory disease with periappendicitis in a pediatric patient

Pelvic inflammatory disease (PID) is generally a disease of young, sexually active patients. However, there have been few reports of computed tomography (CT) and the histopathologic findings of periappendicitis with PID in children. We present a case of PID with periappendicitis in a 12-year-old girl. Her CT findings are described, and the histopathologic findings of periappendicitis are discussed.

New CT criterion for acute appendicitis: maximum depth of intraluminal appendiceal fluid

OBJECTIVE

The purpose of this study was to evaluate whether a new criterion-maximum depth of the intraluminal appendiceal fluid-is useful to differentiate between a normal appendix with diameter greater than 6 mm and appendicitis without periappendiceal inflammation.

MATERIALS AND METHODS

The study included 59 patients showing a normal appendix with diameter greater than 6 mm and having no adjacent lesions (noncomplicated-normal-appendix group), 30 patients showing a normal appendix with diameter greater than 6 mm and having adjacent lesions (complicated-normal-appendix group), and 38 patients showing appendicitis without periappendiceal inflammation (appendicitis group). The following specific CT findings were retrospectively evaluated: maximum appendiceal diameter greater than 6 mm, maximum appendiceal wall thickness greater than 3 mm, appendiceal wall enhancement, focal cecal wall thickening, adjacent adenopathy, appendicolith, and maximum depth of the intraluminal appendiceal fluid.

RESULTS

The mean maximum depth of the intraluminal appendiceal fluid in the appendicitis group was significantly higher than in the two groups with a normal appendix (Mann-Whitney U test: p < 0.001). When using maximum depth of the intraluminal appendiceal fluid greater than 2.6 mm for a criterion of appendicitis, sensitivity and specificity for differentiation between the appendicitis group and the other two groups with a normal appendix were both greater than 80%. In contrast, when using another CT a criterion, either sensitivity or specificity was 50% or less.

CONCLUSION

The new CT criterion based on the maximum depth of the intraluminal appendiceal fluid greater than 2.6 mm is particularly useful for differentiating appendicitis without periappendiceal inflammation from a normal appendix with a diameter greater than 6 mm.

Serosal appendicitis: incidence, causes and clinical significance

BACKGROUND

Serosal appendicitis is a histopathological diagnosis of an inflammatory reaction on the surface of the appendix caused by an extra appendiceal source of inflammation.

OBJECTIVE AND METHODS

A retrospective review of a pathology database in a district general hospital identified patients with serosal appendicitis and a preoperative diagnosis of appendicitis. Two groups emerged: patients with serosal appendicitis secondary to a known cause of intra-abdominal inflammation and those in whom the cause remained unknown. The groups were compared with respect to postoperative complications, referral to outpatient clinics, admissions and procedures by case-note analysis.

RESULTS

The incidence of serosal appendicitis was 0.01% (19/1379); 17 women; mean age 31.63 (10.49) years. Lanz incision was used in 16 patients, midline laparotomy in two and laparoscopy in one. A preoperative ultrasound scan was carried out in 5 of 19 patients. The cause of serosal appendicitis was confirmed in eight patients (intraoperatively or postoperatively) and remained unknown in 11 patients. The groups were comparable with respect to age, sex and mean follow-up. No significant difference was observed between them with respect to the above parameters.

CONCLUSIONS

No further investigation is necessary in patients who undergo an appendicectomy but in whom the pathological diagnosis is serosal appendicitis. However, considering the patient demographics and the fact that patients with serosal appendicitis have probably undergone an unnecessary appendicectomy, the proportion of patients who underwent ultrasound scanning and diagnostic laparoscopy was small.

Routine versus selective abdominal computed tomography scan in the evaluation of right lower quadrant pain: a randomized controlled trial

OBJECTIVES

To determine the role of abdominal computed tomography (CT) imaging in patients with right lower quadrant (RLQ) pain. The authors hypothesized that selective use of abdominal CT would reduce imaging without increasing the rates of negative appendectomy and perforated appendicitis.

METHODS

A prospective randomized clinical trial was conducted in a community teaching emergency department. Adult patients with acute RLQ abdominal pain with suspected acute appendicitis were included. Patients were randomized to mandatory (all patients) or selective (based on clinical evaluation) abdominal CT imaging. The primary outcome was the negative appendectomy rate.

RESULTS

A total of 152 patients were randomized to selective (n = 80) and mandatory (n = 72) intervention groups. The mean (+/-SD) age was 34.1 (+/-3.5) years, and 48% were female. CT imaging was performed in 54 of 80 patients (68%; 95% confidence interval [CI] = 56% to 78%) in the selective group and in 70 of 72 patients (97%; 95% CI = 90% to 100%) in the mandatory group. There was a trend to a decreased rate of negative appendectomy in the mandatory group (1/39 [2.6%]; 95% CI = 0.5% to 13.2%) as compared with the selective group (6/43 [13.9%]; 95% CI = 6.6% to 27.3%), with a difference in prevalence rates of 11.3% (95% CI = -3.5% to 26.3%). There was also a trend to a decreased perforated appendix rate in the mandatory group (4/39 [10.3%]) as compared with the selective group (7/38 [18.4%]), with a difference in prevalence rates of 8.2% (95% CI = -8.0% to 24.4%).

CONCLUSIONS

In this small sample of adult patients with RLQ abdominal pain and suspected acute appendicitis, CT imaging was performed less frequently in the selective group and there was a trend with mandatory CT imaging to reduced rates of negative appendectomy and perforated appendices.

Added value of coronal reformations for duty radiologists and for referring physicians or surgeons in the CT diagnosis of acute appendicitis

Objective

To assess the added value of coronal reformation for radiologists and for referring physicians or surgeons in the CT diagnosis of acute appendicitis.

Materials and Methods

Contrast-enhanced CT was performed using 16-detector-row scanners in 110 patients, 46 of whom had appendicitis. Transverse (5-mm thickness, 4-mm increment), coronal (5-mm thickness, 4-mm increment), and combined transverse and coronal sections were interpreted by four radiologists, two surgeons and two emergency physicians. The area under the receiver operating characteristic curve (Az value), sensitivity, specificity (McNemar test), diagnostic confidence and appendiceal visualization (Wilcoxon signed rank test) were compared.

Results

For radiologists, the additional coronal sections tended to increase the Az value (0.972 vs. 0.986, p = 0.076) and pooled sensitivity (92% [95% CI: 88, 96] vs. 96% [93, 99]), and enhanced appendiceal visualization in true-positive cases (p = 0.031). For non-radiologists, no such enhancement was observed, and the confidence for excluding acute appendicitis declined (p = 0.013). Coronal sections alone were inferior to transverse sections for diagnostic confidence as well as appendiceal visualization for each reader group studied (p < 0.05).

Conclusion

The added value of coronal reformation is more apparent for radiologists compared to referring physicians or surgeons in the CT diagnosis of acute appendicitis.

Length of Stay by Route of Contrast Administration for Diagnosis of Appendicitis by Computed-tomography Scan

OBJECTIVES

Studies show equivalent accuracy of abdominal computed tomography (CT) using rectal contrast compared with oral contrast for diagnosing appendicitis. The authors evaluated whether emergency department (ED) length of stay and satisfaction differed by route of contrast administration for abdominal CT.

METHODS

This before-and-after intervention evaluated adult patients in an urban academic ED who were undergoing abdominal CT to screen for suspected appendicitis. Phase 1 subjects had a CT after oral contrast. Phase 2 patients had a CT after rectal contrast infused by gravity drip. Patients were interviewed after CT scan to assess satisfaction and discomfort. The primary outcome was ED length of stay. Medians, 95% binomial confidence intervals (CI), and Wilcoxon rank sum test of differences were calculated.

RESULTS

One hundred twelve patients were enrolled; half received rectal contrast. There was a significant decrease in length of stay for patients who were administered rectal contrast (261 min, 95% CI = 236 to 305 min) vs. oral contrast (332 min, 95% CI = 299 to 362 min), p = 0.009. Although subjects in the rectal-contrast group waited 65 minutes longer than did oral-contrast patients before receiving contrast after the CT order, the time from contrast administration to CT was 13 minutes, vs. 150 minutes for patients receiving oral contrast (p < 0.001). Patient satisfaction and discomfort did not differ by route of contrast administration.

CONCLUSIONS

Rectal contrast for patients undergoing abdominal CT to rule out appendicitis reduced ED length of stay by more than an hour and did not affect patient satisfaction or discomfort. Rectal-contrast administration for abdominal CT may significantly shorten patient throughput time for individuals undergoing evaluation for appendicitis.

Multidetector Computed Tomography for Suspected Appendicitis

PURPOSE

To determine acquisition protocol parameters currently used by different institutions for appendiceal multidetector computed tomography (MDCT).

MATERIALS AND METHODS

A survey inquiring about multiple MDCT protocols was mailed to 99 fellows of the Society of Computed Body Tomography in August of 2004, with a second mailing sent in May 2005. A total of 46 institutions or hospitals are represented by these Society of Computed Body Tomography fellows. Details pertaining to protocols for the most advanced MDCT scanner in the department were requested.

RESULTS

The overall survey response rate was 17 of 46 or 37%. Fifteen protocols using 16-MDCT for suspected appendicitis were collected and tabulated. Parameters that are similar across institutions include a nonfocused acquisition using oral and intravenous contrast. Detector configuration is even divided between submillimeter and greater than 1 mm, and the most common reconstruction section thickness is 5 mm.

CONCLUSIONS

Contrast administration and anatomical coverage are quite consistent across this set of protocols. However, future appendiceal MDCT research will need to address the most efficacious detector row collimation, reconstruction section thickness and interval, and the diagnostic capacity of protocols implementing dose reduction measures.

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

PURPOSE

To perform a meta-analysis to evaluate the diagnostic performance of ultrasonography (US) and computed tomography (CT) for the diagnosis of appendicitis in pediatric and adult populations.

MATERIALS AND METHODS

Medical literature (from 1986 to 2004) was searched for articles on studies that used US, CT, or both as diagnostic tests for appendicitis in children (26 studies, 9356 patients) or adults (31 studies, 4341 patients). Prospective and retrospective studies were included if they separately reported the rate of true-positive, true-negative, false-positive, and false-negative diagnoses of appendicitis from US and CT findings compared with the positive and negative rates of appendicitis at surgery or follow-up. Clinical variables, technical factors, and test performance were extracted. Three readers assessed the quality of studies.

RESULTS

Pooled sensitivity and specificity for diagnosis of appendicitis in children were 88% (95% confidence interval [CI]: 86%, 90%) and 94% (95% CI: 92%, 95%), respectively, for US studies and 94% (95% CI: 92%, 97%) and 95% (95% CI: 94%, 97%), respectively, for CT studies. Pooled sensitivity and specificity for diagnosis in adults were 83% (95% CI: 78%, 87%) and 93% (95% CI: 90%, 96%), respectively, for US studies and 94% (95% CI: 92%, 95%) and 94% (95% CI: 94%, 96%), respectively, for CT studies.

CONCLUSION

From the diagnostic performance perspective, CT had a significantly higher sensitivity than did US in studies of children and adults; from the safety perspective, however, one should consider the radiation associated with CT, especially in children.

Diagnosis and management of diverticulitis and appendicitis

Diverticulitis and appendicitis are common infections of the gastrointestinal tract that require urgent medical and surgical attention. Successful management of these conditions requires a multidisciplinary approach among primary care providers, gastroenterologists, surgeons, and radiologists. The diagnosis of appendicitis, in particular, can be difficult. Advances in radiographic imaging have improved the diagnostic accuracy in these infections. Minimally invasive surgical techniques have improved the patient's postoperative recovery when surgery is necessary in the management of these conditions.