MP17-01 THE POSTERIOR ACOUSTIC SHADOW: EVALUATING STONE SIZE IN PEDIATRIC STONE FORMERS

Abstract

You have accessJournal of UrologyImaging/Radiology: Uroradiology III1 Apr 2015MP17-01 THE POSTERIOR ACOUSTIC SHADOW: EVALUATING STONE SIZE IN PEDIATRIC STONE FORMERS Franklin Lee, Jonathan Harper, Thomas Lendvay, Ziyue Liu, Barbrina Dunmire, Jonathan Swanson, Manjiri Dighe, Michael Bailey, and Mathew Sorensen Franklin LeeFranklin Lee More articles by this author , Jonathan HarperJonathan Harper More articles by this author , Thomas LendvayThomas Lendvay More articles by this author , Ziyue LiuZiyue Liu More articles by this author , Barbrina DunmireBarbrina Dunmire More articles by this author , Jonathan SwansonJonathan Swanson More articles by this author , Manjiri DigheManjiri Dighe More articles by this author , Michael BaileyMichael Bailey More articles by this author , and Mathew SorensenMathew Sorensen More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2015.02.843AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Unlike adult stone formers, ultrasound is often exclusively used in both the initial diagnosis and the follow-up of pediatric stone formers. As such, treatment decisions are made based on ultrasound findings alone. Ultrasound has been shown to consistently overestimate stone size, which could lead to surgical intervention for a stone that may spontaneously pass. Our group has previously demonstrated that the posterior acoustic shadow is a more accurate predictor of true stone size in an in vitro model. We sought to determine the prevalence and accuracy of the posterior acoustic shadow in a pediatric cohort. METHODS A retrospective analysis was performed of all pediatric stone patient encounters at a children's hospital over the last 10 years using the ICD-9 code for nephrolithiasis (592.0). All included subjects had a stone present on computed tomography (CT) scan and renal ultrasound, taken within 3 months of each other for an initial stone event. The size of the stone and posterior acoustic shadow were measured on ultrasound by two board certified radiologists and compared to stone size as measured on CT. RESULTS Of 633 charts reviewed, 37 patients with 49 kidney stones were included in this study. Mean age was 13 ± 4 years with a mean BMI of 19 ± 6 kg/m2 and mean stone size of 7.2 ± 2.9 based on CT. A posterior acoustic shadow was seen in 85% of stones evaluated and found to be a significantly (p < 0.001) better predictor of true stone size. When compared to CT, measuring the stone directly resulted in an average overestimation of 2.0 ± 1.5 mm, while measuring the acoustic shadow resulted in an underestimation of 0.4 ± 2.5 mm. CONCLUSIONS In this retrospective study, the posterior acoustic shadow was seen in the majority of stones. Measuring the shadow was a more accurate measure of true stone size and may provide valuable prognostic information to help guide clinicians in counseling families about surveillance or surgical management of renal stones. This is particularly relevant to the pediatric population and may reduce unnecessary procedures and further decrease reliance on CT imaging. The results may be improved in a prospective study where the image is optimized for a shadow measurement. © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 4SApril 2015Page: e176 Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information Franklin Lee More articles by this author Jonathan Harper More articles by this author Thomas Lendvay More articles by this author Ziyue Liu More articles by this author Barbrina Dunmire More articles by this author Jonathan Swanson More articles by this author Manjiri Dighe More articles by this author Michael Bailey More articles by this author Mathew Sorensen More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...