Radiological Determination of Stone Density and Skin-to-Stone Distance—Can it Predict the Success of Extracorporeal Shock Wave Lithotripsy?:

Abstract Objectives To determine the role of stone density and skin-to-stone distance (SSD) by non-contrast computed tomography of the kidneys, ureters and bladder (CT-KUB) in predicting the success of extracorporeal shock wave lithotripsy (ESWL). Methods We evaluated 89 patients who received ESWL for renal and upper ureteric calculi measuring 5–20 mm, over a 12 month period. Mean stone density in Hounsfield units (HU) and mean SSD in millimetres (mm) was determined on pre-treatment CT-KUB at the CT workstation. ESWL was successful if post-treatment residual stone fragments were ≤3 mm. Results ESWL success was observed in 68.5% of the patients. Mean stone densities were 505 ± 153 and 803 ± 93 HU in ESWL successful and failure groups, respectively; this was statistically significant ( p t -test). Mean SSD were 10.6 ± 2.0 and 11.2 ± 2.6 cm in ESWL successful and failure groups, respectively, this was not statistically significant. Conclusions This study shows that stone density can help in predicting the outcome of ESWL. We propose that stone densities