Three-Step Sequential Positioning Algorithm During Sonographic Evaluation for Appendicitis Increases Appendiceal Visualization Rate and Reduces CT Use

Chang, Stephanie T.; Jeffrey, R. Brooke; Olcott, Eric W.

doi:10.2214/ajr.13.12334

Cited by 56 publications

(51 citation statements)

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“…We were surprised to find no increase in either accuracy or determinacy despite increasing appendiceal visualization rates over the course of our study. These findings are similar to those of Chang et al [6]. Although efforts toward increased appendiceal visualization and accuracy are important, the actual improvement in patient outcomes that they may achieve is not entirely straightforward.…”

supporting

confidence: 88%

Appendiceal ultrasound: the importance of determinacy

et al. 2015

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"The first job of the radiologist is to minimize doubt."-William E. Shiels, 1954Shiels, -2015 We appreciate the thoughtful comments of Drs. Trout and Larson [1] concerning our article in this issue of Pediatric Radiology and the opportunity to further this discussion with a few additional thoughts. There are striking similarities between our two studies with respect to design and results but there are substantial differences in the conclusions drawn [2,3].Patients referred for US evaluation for acute appendicitis have already been stratified into an indeterminate risk group based on their clinical data. Those thought to have a very high probability of acute appendicitis may be sent directly to surgery and those thought to have a very low probability of appendicitis often are not imaged at all. It is for those patients whose probability of acute appendicitis is indeterminate that clinicians seek our help with US imaging. When clinicians order an imaging test to assist in establishing or excluding the diagnosis of acute appendicitis, they should know the likelihood that the test will provide a determinate result and how accurate that result will be. We presented our appendiceal US data in two ways so as to clearly provide this information to our clinicians. The intention-to-diagnose analysis categorizes indeterminate results as missed cases based on the final outcome. Contrary to Trout and Larson's statement, this analysis is specifically endorsed by Fedko et al. [4] because it allows for "transparent reporting of all results and determination of diagnostic yield" and likelihood ratios and informs physicians what proportion of appendiceal US examinations will not yield determinate results. The intention-to-diagnose method does underestimate measures of the diagnostic performance of US such as accuracy and sensitivity for the determinate results. To account for this, we performed a second analysis using the standard binary approach that excludes indeterminate studies because this analysis relates to clinicians the accuracy of appendiceal US when a determinate result is given.In our opinion, indeterminate results do not yield useful information. Trout and Larson think they do. They assert that indeterminate results reflect a range of probabilities that a given patient has appendicitis and that this information is meaningful to clinicians. While we did find a narrow range of prevalences of appendicitis in our three indeterminate groups, we disagree that this information is clinically useful. Our findings do not support their assertion on two grounds.

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confidence: 88%

Appendiceal ultrasound: the importance of determinacy

et al. 2015

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“…(37.7%) and Chang et al . (35.1%–58.5%), yet significantly lower than other studies that have identified up to an exceptionally high 99% of appendices . This may indicate important differences that provide potential for improvement or a more systematic approach to visualising the appendix.…”

Section: Discussionmentioning

confidence: 63%

Sonographic diagnosis of acute appendicitis in children: a 3‐year retrospective

et al. 2016

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Introduction: Ultrasound is commonly used as a tool for investigation of acute appendicitis in children. The accuracy of ultrasound in appendicitis depends on the ability to visualise the appendix and the potential contribution from secondary signs. The study was a retrospective analysis of children referred for sonographic investigation of possible acute appendicitis at an Australian Methods: Radiology reports, ultrasound images and electronic medical records were evaluated for eligible patients. The ability to visualise the appendix and determine secondary sonographic signs was evaluated for diagnostic accuracy.Results: The study identified 457 eligible children, with the appendix visualised on ultrasound in 40.7% of cases. Using a binary diagnostic model that incorporated equivocal results, sensitivity of ultrasound to diagnose acute appendicitis was 88.1%, specificity 91.4% and accuracy 90.4%. Ultrasound was found to have a high negative predictive value (96.3%), and the presence of echogenic mesentery had a positive predictive value of 89.4%. Discussion:Our results compare favourably with other studies, but indicate the potential for improvement in accuracy and visualisation, with a future study incorporating new methods of categorising ultrasound findings currently being undertaken.Funding: This manuscript is based on research performed as part of a higher research degree at Queensland University of Technology (QUT), Brisbane, Australia. Conflict of interest: None.Sonography 3 87-94

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“…Graded compression appendiceal US was performed by a group of six ultrasonographers, each with at least 5 years of experience in appendiceal US, following our standard clinical protocol with long-and short-axis gray-scale US imaging with graded compression (27,35,36). To facilitate visualization of the appendix, we routinely utilized a three-step positioning algorithm in which patients were scanned sequentially, as necessary, in the supine, left posterior oblique, and "second-look" supine positions (37). US images were the criterion of PSV greater than 10 cm/sec and the criterion of RI greater than 0.65 (Table) compared favorably with the specificity of the original clinical graded compression US interpretations produced without spectral Doppler information (51 of 53, 96.2%; 95% CI: 87.0%, 99.5%); however, the original clinical graded compression US interpretations included equivocal results approximately 95% included PSV greater than 10 cm/sec and RI greater than 0.65, which produced specificity of 94.7% and 96.5%, sensitivity of 88.9% and 63.9% (P = .013), and negative predictive value of 93.1% and 80.9%, respectively (Table).…”

Section: Appendiceal Us Techniquementioning

confidence: 99%

Spectral Doppler Waveforms for Diagnosis of Appendicitis: Potential Utility of Point Peak Systolic Velocity and Resistive Index Values

et al. 2017

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Purpose To test the hypothesis that appendiceal spectral Doppler waveforms can distinguish patients with and patients without appendicitis. Materials and Methods In this retrospective study, Doppler waveforms were obtained from intramural appendiceal arteries identified with color Doppler imaging in 60% (93 of 155) of consecutive patients whose appendices were visualized at graded compression ultrasonography (US) performed for suspected appendicitis (53 male and 40 female; age, 1-56 years; mean, 14.5 years) over the 5-month period from November 2015 through March 2016. Point, non-angle-corrected peak systolic velocity (PSV) and resistive index (RI) values were compared between patients with and patients without appendicitis by utilizing histopathologically proven appendicitis and 6-week clinical follow-up as diagnostic reference standards. Data were assessed by using the Student t test, exact binomial distribution, two-sample test of proportions, and receiver operating characteristic analysis. Results Among the 93 patients, 36 (38.7%) had proven appendicitis (mean PSV, 19.7 cm/sec; mean RI, 0.69) and 57 patients (61.2%) did not (mean PSV, 7.1 cm/sec, P < .0001; mean RI, 0.50, P < .0001). The area under the receiver operating characteristic curve for the diagnosis of appendicitis was 0.97 (95% confidence interval [CI]: 0.95, 1.00) for PSV and 0.86 (95% CI: 0.78, 0.95; P = .011) for RI. Chosen discriminatory criteria of PSV greater than 10 cm/sec and RI greater than 0.65 yielded specificity for appendicitis of 94.7% and 96.5% with sensitivity of 88.9% and 63.9% (P = .013) and negative predictive value of 93.1% and 80.9% (P = .045), respectively. Original clinical graded compression US interpretations based on established US findings demonstrated specificity of 96.2% and sensitivity of 100.0%. Considering the subset of 20 patients whose maximum outer diameter measured 6-8 mm, the discriminatory criteria of PSV greater than 10 cm/sec and RI greater than 0.65 yielded specificity for appendicitis of 88.9% each, with sensitivity of 100.0% and 63.6% and negative predictive value of 100.0% and 66.6%, respectively. Conclusion In patients with visualized appendices at US, those with appendicitis exhibit significantly higher point PSV and point RI values than do patients without appendicitis and are distinguishable with high specificity by using a PSV greater than 10 cm/sec and an RI greater than 0.65 as diagnostic criteria. RSNA, 2017.

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Three-Step Sequential Positioning Algorithm During Sonographic Evaluation for Appendicitis Increases Appendiceal Visualization Rate and Reduces CT Use

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

Cited by 56 publications

References 25 publications

Appendiceal ultrasound: the importance of determinacy

Appendiceal ultrasound: the importance of determinacy

Sonographic diagnosis of acute appendicitis in children: a 3‐year retrospective

Spectral Doppler Waveforms for Diagnosis of Appendicitis: Potential Utility of Point Peak Systolic Velocity and Resistive Index Values

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