Two-dimensional shear wave elastography can improve the diagnostic accuracy of ultrasonography in acute appendicitis

AIM

We aimed to evaluate the effectiveness of combining 2-dimensional shear wave elastography (2D-SWE) with ultrasonography (US) in diagnosing acute appendicitis in patients with suspected acute appendicitis.

METHODS

Clinical and laboratory findings, gray-scale US and 2D-SWE imaging features, operation information, and pathology results of 48 patients diagnosed with acute appendicitis who presented with right lower quadrant pain were prospectively evaluated. We compared the findings to the US and SWE imaging features of 79 asymptomatic patients.

RESULTS

Mean Alvarado score and appendix diameter were statistically significantly higher for acute appendicitis (p < 0.001). In patients with acute appendicitis, mesenteric lymphadenopathy and fat stranding were also more frequent (p < 0.001). The mean velocity and kPa values for appendix and mesenteric fat were statistically significantly higher in acute appendicitis (p < 0.001).

CONCLUSION

In the diagnosis of acute appendicitis, 2D-SWE increases the diagnostic performance of gray-scale US in the differentiation of inflamed and normal appendixes.

INVESTIGATION OF RADIATION RISKS BASED ON THE CLINICAL FINDINGS FROM HEAD CT SCANS IN TRAUMA

This study aimed to investigate the radiation risks in terms of effective dose and the cancer risk probability resulting from computed tomography (CT) scans of the head for traumatic patients and determine how often traumatic abnormalities occur. Data were collected retrospectively for 138 traumatic patients from the picture archiving and communication system, including exposure parameters and clinical findings. The mean values of the dose length product, CT dose index volume and effective dose for the CT head examinations were 787 ± 67.7 mGy•cm, 40.1 ± 1.33 mGy and 1.47 ± 0.12 mSv, respectively. Of the total cases of CT scans of the head, 57.2% (n = 79) exhibited positive findings. The cancer risk probability for the patients was 6.04 × 10-5 per procedure, with no statistically significant differences between positive and negative findings (p = 0.345). Taking into consideration the justification of the examination, the risk of missing positive findings and the radiation risks, the immediate benefit of head CT for trauma patients for guiding medical decisions outweighs the radiation risk that will probably manifest later.

Diagnostic accuracy of computed tomography and ultrasound for the diagnosis of acute appendicitis: A systematic review and meta-analysis

INTRODUCTION

The diagnosis of acute appendicitis remains challenging. This review determined the current diagnostic accuracy of CT and ultrasound for suspected acute appendicitis in adults.

METHODS

This systematic review adhered to the PRISMA for diagnostic test accuracy guidelines. A systematic search was undertaken in appropriate databases. Screening of potential titles and abstracts, full-text retrieval, methodological quality assessment using QUADAS, and data extraction was performed. Meta-analyses were performed for relevant subgroups, and sensitivity analysis was completed to account for outliers. GRADE was utilized to assess the certainty of findings.

RESULTS

31 studies evaluating CT, 10 evaluating US, and six evaluating both were included. Pooled sensitivity and specificity for CT was 0.972 [0.958, 0.981] and 0.956 [0.941, 0.967] respectively, and 0.821 [0.738, 0.882] and 0.859 [0.727, 0.933] for US, respectively. When analyzing subgroups based on the use of contrast enhancement, sensitivity and specificity was highest for CT with intravenous and oral contrast (0.992 [0.965, 0.998], 0.974 [0.936, 0.99]), compared to CT with intravenous contrast (0.955 [0.922, 0.974], 0.942 [0.916, 0.960]). Low-Dose CT produced comparable values (0.934 [0.885,0.963], 0.937 [0.911, 0.955]) relative to these subgroups and standard dose non-contrast CT (0.877 [0.774,0.937], 0.914 [0.827, 0.959]). US studies which excluded equivocal findings demonstrated significantly greater values than the remainder of US studies (p < 0.0001).

CONCLUSION

The updated diagnostic test accuracies of CT, US and relevant subgroups should be implemented in light of factors such as dose, cost, and timing.

IMPLICATIONS FOR PRACTICE

For diagnosis of adult acute appendicitis: • CT with intravenous plus oral contrast enhancement yields statistically significantly greater diagnostic accuracy than CT with intravenous contrast alone. • Low-dose CT yields comparable sensitivity and specificity to standard-dose CT. • Ultrasound studies which exclude equivocal results may overinflate sensitivity and specificity.

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.

Neutrophil-to-lymphocyte ratio predicts acute appendicitis and distinguishes between complicated and uncomplicated appendicitis: A systematic review and meta-analysis

OBJECTIVES

to investigate whether Neutrophil-to-lymphocyte ratio (NLR) can predict acute appendicitis and whether it can distinguish between uncomplicated and complicated appendicitis.

METHODS

A search of electronic information sources was conducted to identify all studies reporting NLR in patients with clinical suspicion or confirmed diagnosis of acute appendicitis. We considered two comparisons:1) appendicitis versus no appendicitis; 2) uncomplicated appendicitis versus complicated appendicitis. ROC curve analysis was performed to determine cut-off values of NLR for appendicitis and complicated appendicitis.

RESULTS

Seventeen studies, enrolling 8,914 patients were included. NLR of 4.7 was cut-off value for appendicitis with sensitivity of 88.89% and specificity of 90.91% with AUC of 0.96. NLR of 8.8 was cut-off value for complicated appendicitis with sensitivity of 76.92% and specificity 100% with AUC of 0.91. NLR >4.7 was predictor of acute appendicitis (OR:128,P < 0.0001) and, NLR >8.8 was predictor of complicated appendicitis (OR:43,P < 0.0001).

CONCLUSIONS

NLR predicts both diagnosis and severity of appendicitis. This may have implications for prioritising cases for surgery, for monitoring conservatively treated patients and for patients who do not routinely undergo CT scan (pregnant or paediatric patients).

Access to primary care and computed tomography use in the emergency department

Background

The decision to obtain a computed tomography CT scan in the emergency department (ED) is complex, including a consideration of the risk posed by the test itself weighed against the importance of obtaining the result. In patients with limited access to primary care follow up the consequences of not making a diagnosis may be greater than for patients with ready access to primary care, impacting diagnostic reasoning. We set out to determine if there is an association between CT utilization in the ED and patient access to primary care.

Methods

We performed a cross-sectional study of all ED visits in which a CT scan was obtained between 2003 and 2012 at an academic, tertiary-care center. Data were abstracted from the electronic medical record and administrative databases and included type of CT obtained, demographics, comorbidities, and access to a local primary care provider (PCP). CT utilization rates were determined per 1000 patients.

Results

A total of 595,895 ED visits, including 98,001 visits in which a CT was obtained (16.4%) were included. Patients with an assigned PCP accounted for 55% of all visits. Overall, CT use per 1000 ED visits increased from 142.0 in 2003 to 169.2 in 2012 (p < 0.001), while the number of annual ED visits remained stable. CT use per 1000 ED visits increased from 169.4 to 205.8 over the 10-year period for patients without a PCP and from 118.9 to 142.0 for patients with a PCP. Patients without a PCP were more likely to have a CT performed compared to those with a PCP (OR 1.57, 95%CI 1.54 to 1.58; p < 0.001). After adjusting for age, gender, year of visit and number of comorbidities, patients without a PCP were more likely to have a CT performed (OR 1.20, 95% CI 1.18 to 1.21, p < 0.001).

Conclusions

The overall rate of CT utilization in the ED increased over the past 10 years. CT utilization was significantly higher among patients without a PCP. Increased availability of primary care, particularly for follow-up from the ED, could reduce CT utilization and therefore decrease costs, ED lengths of stay, and radiation exposure.

Pitfalls and mimickers at 64-section helical CT that cause negative appendectomy: an analysis from 1057 appendectomies

PURPOSE

To determine the rate of negative appendectomy and clarify the causes of negative appendectomy in patients with clinically suspected acute appendicitis who had surgery after 64-section helical computed tomography (CT).

MATERIAL AND METHODS

A retrospective analysis of 1057 patients who had appendectomy after 64-section helical CT was performed to determine the rate of negative appendectomy. The 64-section helical CT examinations obtained with submillimeter and isotropic voxels in the patients with negative appendectomy were analyzed by two readers and compared to clinical, operative and histopathological reports, discharge summaries and original radiology reports.

RESULTS

The negative appendectomy rate was 1.7% (18/1057). Appendix enlargement (>6 mm) and fat stranding were present in 17 (17/18; 94%) and 6 patients (6/18; 33%), respectively. In 13 patients (13/18; 72%) 64-section helical CT findings were consistent with acute appendicitis. Interpretive errors in original imaging reports were identified in five patients (5/18; 28%).

CONCLUSION

The preoperative use of 64-section helical CT results in a very low rate of negative appendectomy. Patients with negative appendectomy have 64-section helical CT findings consistent with a diagnosis of acute appendicitis in the majority of cases. Interpretive errors are less frequent.

Emergency department computed tomography utilization in the United States and Canada

STUDY OBJECTIVE

We compare secular trends in computed tomography (CT) utilization in emergency departments (EDs) in the United States and Ontario, Canada.

METHODS

Using a systematic survey in the US (The National Hospital Ambulatory Medical Care Survey) and administrative databases in Ontario, we performed a retrospective study of ED visits from 2003 to 2008. We calculated utilization overall, by visit characteristics, and for 5 clinical conditions in which CT is commonly indicated: abdominal pain, complex abdominal pain (abdominal pain, age ≥65 years, urgent to most urgent triage), admitted complex abdominal pain (abdominal pain, age ≥65 years, urgent to most urgent triage, and admitted to hospital), headache, and chest pain/shortness of breath. US data were weighted to produce national estimates.

RESULTS

On-site CT was available for 97% (95% confidence interval [CI] 95% to 99%) of visits in the United States compared with 80% (95% CI 80% to 80%) in Ontario. Visits were more frequently triaged as higher acuity in the United States than in Ontario, with 15.1% (95% CI 13.9% to 16.4%) of US visits categorized as most urgent versus 11.8% (95% CI 11.8% to 11.8%) in Ontario. The proportion of all ED visits in which CT was performed was 11.4% (95% CI 10.8% to 12.0%) in the United States versus 5.9% (95% CI 5.9% to 5.9%) in Ontario. The proportion for children was 4.7% (95% CI 4.3% to 5.1%) in the United States versus 1.4% (95% CI 1.4% to 1.4%) in Ontario. The rate of visits involving CT per year increased faster from 2003 to 2008 in the United States (odds ratio 2.00; 95% CI 1.81 to 2.21) than Ontario (odds ratio 1.69; 95% CI 1.68 to 1.70). Over time, all subgroups experienced increases in CT rate except Ontario children younger than 10 years, who experienced a significant decrease. United States-Ontario differences in CT proportions were significant among patients presenting with headache, abdominal pain, chest pain/shortness of breath, and complex abdominal pain. Proportions for visits involving admitted complex abdominal pain in the two jurisdictions were indistinguishable: 45.8% in the United States (95% CI 39.9% to 51.7%) versus 44.7% (95% CI 44.4% to 45.0%) in Ontario.

CONCLUSION

CT was more readily available in US EDs, and US clinicians used the technology more frequently than their colleagues in Ontario for nearly every category of patients, including children. CT utilization increased over time in both jurisdictions, but faster in the United States. Different demographic features between the two jurisdictions, including triage severity, frequency of hospitalization, and availability of CT scanners, likely account for at least some of the differences in CT utilization. Investigation of both clinical and nonclinical reasons for the differences in CT utilization between the United States and Canada would be a fruitful area for further research.

Sex differences in the epidemiology, seasonal variation, and trends in the management of patients with acute appendicitis

BACKGROUND

Acute appendicitis is the most common indication for acute surgical abdominal intervention. In this study, we analyzed the gender correlation with demographic, epidemiologic, diurnal, and seasonal trends in relation to the incidence and management of patients with acute appendicitis in our medical center.

METHODS

Data of patients, 18 years of age or older who underwent emergency appendectomies at the Rabin Medical Center during the last 13 years, were collected. The data collected included demographic parameters, hospitalization, procedures, and use of preoperative imaging.

RESULTS

Data were available for 3,736 patients. Males had more appendicitis attacks than females (p < 0.0001), whereas females had more normal appendixes than males (p < 0.0001). The overall rate of normal appendixes was 19.6 %, with a decline in the past 10 years from a yearly average of 23.5 % between 1998 and 2002 to 15 % between 2003 and 2007 (p < 0.0001) with a reverse correlation with the preoperative use of abdominal CT. A distinct seasonal pattern was observed; more appendectomies for acute appendicitis occurred during the summer months (p < 0.0001). Ten percent of patients had a complicated course with a mortality rate of 0.33 %; most of them were elderly, male/female ratio 0.4.

CONCLUSIONS

We found distinct gender, epidemiological, seasonal, and diurnal trends influencing the incidence of acute appendicitis. The incidence rate of false-positive surgery has been gradually declining, probably due to the increased use of preoperative abdominal CT and ultrasound. Acute appendicitis was more common in males and during the summer months.

Acute appendicitis: prospective evaluation of a diagnostic algorithm integrating ultrasound and low-dose CT to reduce the need of standard CT

OBJECTIVES

To evaluate an algorithm integrating ultrasound and low-dose unenhanced CT with oral contrast medium (LDCT) in the assessment of acute appendicitis, to reduce the need of conventional CT.

METHODS

Ultrasound was performed upon admission in 183 consecutive adult patients (111 women, 72 men, mean age 32) with suspicion of acute appendicitis and a BMI between 18.5 and 30 (step 1). No further examination was recommended when ultrasound was positive for appendicitis, negative with low clinical suspicion, or demonstrated an alternative diagnosis. All other patients underwent LDCT (30 mAs) (step 2). Standard intravenously enhanced CT (180 mAs) was performed after indeterminate LDCT (step 3).

RESULTS

No further imaging was recommended after ultrasound in 84 (46%) patients; LDCT was obtained in 99 (54%). LDCT was positive or negative for appendicitis in 81 (82%) of these 99 patients, indeterminate in 18 (18%) who underwent standard CT. Eighty-six (47%) of the 183 patients had a surgically proven appendicitis. The sensitivity and specificity of the algorithm were 98.8% and 96.9%.

CONCLUSIONS

The proposed algorithm achieved high sensitivity and specificity for detection of acute appendicitis, while reducing the need for standard CT and thus limiting exposition to radiation and to intravenous contrast media.

Negative appendectomy rate in the era of CT: an 18-year perspective

PURPOSE

To estimate the correlation between the negative appendectomy rate (NAR) and the rate of preoperative computed tomography (CT) in patients suspected of having acute appendicitis who presented to the emergency department during an 18-year period.

MATERIALS AND METHODS

This retrospective institutional review board-approved, HIPAA-compliant study was performed in a 719-bed tertiary care adult teaching hospital with 58,000 annual emergency department visits. The authors obtained a waiver of informed consent and used the medical records system to compare patients suspected of having appendicitis who presented to the emergency department between 2003 and 2007 to those who presented between 1990 and 1994, the period just before CT became commonly used at the authors' institution for the evaluation of appendicitis. Surgical and pathology reports were reviewed to determine the NAR, and the authors queried the radiology databases to determine the proportion of appendectomy patients who underwent preoperative imaging. Outcome measures included the NAR, the proportion of appendectomy patients who underwent preoperative CT, and the annual number of appendectomies performed. The chi(2) test for trend was used to assess for changes in proportions, and linear regression was used to evaluate numeric trends.

RESULTS

From 1990 to 2007, the NAR decreased significantly from 23.0% to 1.7% (P < .0001), the annual number of appendectomies decreased significantly from 217 per year to 119 per year (P = .0003), and the proportion of patients undergoing appendectomy who underwent preoperative CT increased significantly from 1% to 97.5% (P < .0001).

CONCLUSION

There was a significant reduction in both the NAR and the number of appendectomies in patients who presented to the emergency department during an 18-year period, which was associated with a significant increase in the use of preoperative abdominal CT.

Unenhanced MR Imaging in adults with clinically suspected acute appendicitis

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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