Stone size calculator
With increasing frequency patients who present with kidney stones are
undergoing computed tomography (CT) scans as an initial imaging study.
Much of the management of kidney stones is based on stone size, but
the same stone may appear larger on a conventional X-ray film (KUB)
than on CT. The following Javascript calculator computes the apparent
size of a kidney stone on KUB given the measured size on CT. Default
values are given for the University of Illinois at Chicago KUB
radiographic system (plate surface to film distance w is taken into
account when measuring patient's dorsum to plate distance y2, hence
the default value of 0 for w).
If you like, you may use Nakada's algorithm (Stephen Y. Nakada, Douglas
G. Hoff, Sherwin Attai, Dennis Heisey, Donna Blankenbaker, and Myron
Pozniak, "Determination of Stone Composition by Noncontrast Spiral
Computed Tomography in the Clinical Setting", Urology 55 (6),
2000, pp. 816-819) to predict stone composition from Hounsfield unit
density.
At the bottom of this page, you can download this calculator for a
PalmPilot or Handspring device.
