title: Stone-Mode Ultrasound for Determining Renal Stone Size.
abstract: The purpose of this study was to measure the accuracy of stone-specific algorithms (S-mode) and the posterior acoustic shadow for determining kidney stone size with ultrasound (US) in vivo.
  
  
  
  Thirty-four subjects with 115 renal stones were prospectively recruited and scanned with S-mode on a research US system. S-mode is gray-scale US adjusted to enhanced stone contrast and resolution by minimizing compression and averaging, and increasing line density and frequency. Stone and shadow width were compared with a recent CT scan and, in 5 subjects with 18 stones, S-mode was compared with a clinical US system.
  
  
  
  Overall, 84% of stones identified on CT were detected on S-mode and 66% of these shadowed. Seventy-three percent of the stone measurements and 85% of the shadow measurements were within 2 mm of the size on CT. A posterior acoustic shadow was present in 89% of stones over 5 mm versus 53% of stones under 5 mm. S-mode visualized 78% of stones, versus 61% for the clinical system. S-mode stone and shadow measurements differed from CT by 1.6 ± 1.0 mm and 0.8 ± 0.6 mm, respectively, compared with 2.0 ± 1.5 mm and 1.6 ± 1.0 mm for the clinical system.
  
  
  
  S-mode offers improved visualization and sizing of renal stones. With S-mode, sizing of the stone itself and the posterior acoustic shadow were similarly accurate. Stones that do not shadow are most likely <5 mm and small enough to pass spontaneously.
authors.affiliation: 1 Department of Urology, University of Washington , Seattle, Washington.|2 Center for Industrial and Medical Ultrasound, University of Washington Applied Physics Lab , Seattle, Washington.
authors.forename: Philip C
authors.initials: PC
authors.lastname: May
authors.affiliation: 2 Center for Industrial and Medical Ultrasound, University of Washington Applied Physics Lab , Seattle, Washington.
authors.forename: Yasser
authors.initials: Y
authors.lastname: Haider
authors.affiliation: 2 Center for Industrial and Medical Ultrasound, University of Washington Applied Physics Lab , Seattle, Washington.
authors.forename: Barbrina
authors.initials: B
authors.lastname: Dunmire
authors.affiliation: 2 Center for Industrial and Medical Ultrasound, University of Washington Applied Physics Lab , Seattle, Washington.
authors.forename: Bryan W
authors.initials: BW
authors.lastname: Cunitz
authors.affiliation: 3 Department of Radiology, University of Washington , Seattle, Washington.
authors.forename: Jeff
authors.initials: J
authors.lastname: Thiel
authors.affiliation: 4 Department of Biostatistics, Indiana University , Indianapolis, Indiana.
authors.forename: Ziyue
authors.initials: Z
authors.lastname: Liu
authors.affiliation: 2 Center for Industrial and Medical Ultrasound, University of Washington Applied Physics Lab , Seattle, Washington.
authors.forename: Matthew
authors.initials: M
authors.lastname: Bruce
authors.affiliation: 1 Department of Urology, University of Washington , Seattle, Washington.|2 Center for Industrial and Medical Ultrasound, University of Washington Applied Physics Lab , Seattle, Washington.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Bailey
authors.affiliation: 1 Department of Urology, University of Washington , Seattle, Washington.|5 Division of Urology, Department of Veteran Affairs Medical Center , Seattle, Washington.
authors.forename: Mathew D
authors.initials: MD
authors.lastname: Sorensen
authors.affiliation: 1 Department of Urology, University of Washington , Seattle, Washington.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Harper
mesh_terms: D000162:Acoustics; D000328:Adult; D000368:Aged; D000465:Algorithms; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography / Q000379:methods*