Differentiation of ureteral stones and phleboliths using Hounsfield units on computerized tomography: a new method without observer bias

Urolithiasis. 2017 Jun;45(3):323-328. doi: 10.1007/s00240-016-0918-1. Epub 2016 Sep 16.


To differentiate ureteral stones and phleboliths by measuring density [as Hounsfield unit (HU)] and volume (as mm3) of the opacities in the bony pelvis on unenhanced computerized tomography (U-CT). A total of 52 patients, who underwent semirigid ureteroscopy and laser lithotripsy for distal ureteral stone and had isochoronous phleboliths in U-CT, were included. Images were reviewed for density and volume of the opacities. Data were compared, and a cut-off value was defined with receiver operating characteristics curve analysis to differentiate the nature of the opacity. Using the cut-off values of 171 mm³ for volume (sensitivity 75 %, specificity 100 %) and 643 HU for density (sensitivity 75 %, specificity 93 %), differentiation between stone and phlebolith was achieved. Differentiation of pelvic opacities needs meticulous observation with certain signs on U-CT. On the other hand, our study offers a new method, with certain cut-off values, such as 643 HU and 171 mm3, which can be used to precisely predict the actual nature of opacities of interest.

Keywords: Diagnosis; Hounsfield unit; Imaging; Ureteral stones; Ureteroscopy.

Publication types

  • Comparative Study
  • Evaluation Study

MeSH terms

  • Case-Control Studies
  • Diagnosis, Differential
  • Humans
  • Lithotripsy, Laser
  • Observer Variation
  • Pelvis / diagnostic imaging
  • ROC Curve
  • Retrospective Studies
  • Sensitivity and Specificity
  • Tomography, X-Ray Computed / methods*
  • Ureteral Calculi / diagnostic imaging*
  • Ureteral Calculi / therapy*
  • Ureteroscopy
  • Vascular Calcification / diagnostic imaging*