Color Doppler imaging of pure crystals in hyperbaric conditions

Abstract

The color Doppler ultrasound twinkling artifact is a rapid color shift that appears on some kidney stones and other pathological mineralizations during ultrasound imaging. Twinkling on kidney stones is primarily attributed to scattering from stabilized microbubbles as increasing hydrostatic pressures has been shown to decrease twinkling. However, it is unknown whether microbubbles are also present and cause twinkling on other forms of pathological mineralizations or pure crystals. In this study, 5 cholesterol and 5 calcium phosphate crystals were grown in vitro from supersaturated solutions and imaged in a custom-built, hydrostatic pressure chamber with a Philips/ATL L7-4 transducer and Vantage-128 research ultrasound system. Hydrostatic pressure was increased to a maximum of 14 MPa while saving IQ data at 1 fps for evaluation of Doppler power. On all 10 imaged crystals, twinkling was found to decrease by approximately 90% when pressures reached 4 MPa absolute. Twinkling reappeared when the pressure was returned to atmospheric levels. These results suggest that bubbles are present on pure crystals and give rise to the twinkling artifact. [Work supported by NSF CAREER 1943937 and NSF GRFP DGE1255832.]