576 NONINVASIVE GRADE V VESICOURETERAL REFLUX DETECTION: AN ANIMAL STUDY

Abstract

You have accessJournal of UrologyPediatrics: Imaging/Infections & Vesicoureteral Reflux1 Apr 2011576 NONINVASIVE GRADE V VESICOURETERAL REFLUX DETECTION: AN ANIMAL STUDY Brent Snow, Kavitha Arunchalam, Valeria De Luca, Oystein Klemetsen, Yngve Birkelund, Paul Stauffer, and Paolo Maccarini Brent SnowBrent Snow Salt Lake City, UT More articles by this author , Kavitha ArunchalamKavitha Arunchalam Durham, NC More articles by this author , Valeria De LucaValeria De Luca Zurich, Switzerland More articles by this author , Oystein KlemetsenOystein Klemetsen Tromso, Norway More articles by this author , Yngve BirkelundYngve Birkelund Tromso, Norway More articles by this author , Paul StaufferPaul Stauffer Durham, NC More articles by this author , and Paolo MaccariniPaolo Maccarini Durham, NC More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2011.02.1386AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES A new noninvasive device is being developed for vesicoureteral reflux (VUR) detection. The concept is to comfortably warm the bladder transcutaneously with microwave antennas placed on the lower abdomen to 40–43¢XC. Kidney temperatures will be measured before and after bladder warming with a microwave receiving antenna placed on the skin surface and connected to a radiometer. When reflux of the warmed urine from the bladder occurs, kidney temperature will rise and reflux will be detected noninvasively. Reflux grade should correlate to the amount of heat detected. This study measures Grade V VUR detection. METHODS CT scans of 2–5 year old patients were digitized and computer simulations were used to design microwave antennas with directional receive pattern and electromagnetic (EM) shielding for passive kidney temperature monitoring. The antenna coupled to a radiometer with 550 MHz bandwidth centered at 1.375 GHz was then tested in a layered tissue phantom mimicking the electromagnetic properties of fat, muscle and kidney tissues to assess radiometric kidney temperature monitoring. Subsequently, the system was tested on a 15 Kg swine (the average weight of a 3.5 year old patient). A 30 ml inflatable Foley catheter was placed in the renal fossa and an ultrasound scan confirmed its location 3cm deep from the skin. In order to amplify our success, 42¢XC saline was circulated through the Foley catheter (chosen to represent significant Grade V VUR). The temperature change at depth was passively monitored using a radiometric antenna placed on the pig skin and directed towards the kidney renal fossa. The procedure was repeated with intermittent flow of warm saline and measurements were continually recorded. RESULTS Our EM shielded receive antenna connected to the 1.375 GHz radiometer yielded very stable readings in correlation with the temperature of the saline circulating inside the Foley catheter at 3.5 cm depth. The constant and intermittent temperature changes of about 5„aC from baseline could be detected in real time with a resolution of 0.002 dBm per degree Celsius temperature change at depth. CONCLUSIONS Temperature changes of about 5¢XC sufficient to detect Grade V VUR in animals were reliably detected using microwave radiometry. © 2011 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 185Issue 4SApril 2011Page: e232 Advertisement Copyright & Permissions© 2011 by American Urological Association Education and Research, Inc.MetricsAuthor Information Brent Snow Salt Lake City, UT More articles by this author Kavitha Arunchalam Durham, NC More articles by this author Valeria De Luca Zurich, Switzerland More articles by this author Oystein Klemetsen Tromso, Norway More articles by this author Yngve Birkelund Tromso, Norway More articles by this author Paul Stauffer Durham, NC More articles by this author Paolo Maccarini Durham, NC More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...