Stone-mode ultrasound for determining renal stone size

Philip C. May, Yasser Haider, Barbrina Dunmire, Bryan W. Cunitz, Jeff Thiel, Ziyue Liu, Matthew Bruce, Michael R. Bailey, Mathew D. Sorensen, Jonathan D. Harper

Research output: Contribution to journalArticle

11 Scopus citations


Purpose: 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. Materials and Methods: 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. Results: 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. Conclusions: 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.

Original languageEnglish (US)
Pages (from-to)958-962
Number of pages5
JournalJournal of Endourology
Issue number9
StatePublished - Sep 1 2016

ASJC Scopus subject areas

  • Medicine(all)
  • Urology

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    May, P. C., Haider, Y., Dunmire, B., Cunitz, B. W., Thiel, J., Liu, Z., Bruce, M., Bailey, M. R., Sorensen, M. D., & Harper, J. D. (2016). Stone-mode ultrasound for determining renal stone size. Journal of Endourology, 30(9), 958-962.