Radiological Density, Atomic Numbers and Stone Fragmentation of Bego Stones Used for Research on Endourology. Comparison to Real Urinary Stones.

The aim of the study was to characterize artificial stones which are used for research in endourology from the perspective of radiological properties and hardness in terms of stone fragmentation, and to compare them to real stones from those assessments. We built artificial stones from BegoStone Plus powder (BEGO Lincoln, RI, USA) with powder(grams): water(ml) ratios from 15:03 to 15:12. The CT Gemstone Spectral Imaging Software (GE Medical Systems, LLC. Waukesha, WI, U.S.A) was used to evaluate the radiological density in Hounsfield Units (HU) and spectral properties. Stone fragmentation was assessed with an in vitro experimental setting. Artificial stones were compared to real urinary calculi from those perspectives. Regarding radiological density in terms of HU, 15:03 artificial calculi showed similar results compared to real stones composed of Calcium Oxalate and Calcium Phosphate. Spectral properties wise, 15:03 and 15:04 artificial stones showed similar results than calcium pyrophosphate stones. Stone fragmentation wise, 15:11 artificial stones showed similar results than real stones composed of uric acid. 15:03 artificial calculi showed similar results than apatite and cystine stones. Artificial stones are very useful for research in endourology. Stones with a gr of powder: ml water ratio of 15:03 proved to mimic hard real stones in terms of HU, atomic number and stone fragmentation in our study and could be used as artificial hard stones. 15:11 stones showed similar stone fragmentation than uric acid stones. Our study might suggest that standard Bego stones are a very useful material to investigate different areas in endourology but not radiological properties because radiological homogeneity is not ensured unless using more sophisticated mixing methods.