The effect of gas composition on the color Doppler ultrasound twinkling artifact

Abstract

The twinkling artifact, or twinkling, appears when imaging kidney stones and other mineralizations with Doppler ultrasound and is caused by scattering off crevice microbubbles. Previous work found that twinkling on in vivo kidney stones increased or decreased with elevated oxygen or carbon dioxide, respectively. However, it is unclear whether these results are from biological adaptions to the changing respiratory gas and thus if in vitro mineralizations are similarly affected. Here, cholesterol, calcium phosphate, and uric acid crystals were grown in vitro and imaged in deionized water using a Vantage-128 research ultrasound system with a Philips/ATL L7-4 transducer. Five of each crystal composition were imaged for one minute at different dissolved gas concentrations. By bubbling gas through water, dissolved oxygen ranged from 2 to 20 mg/L while dissolved carbon dioxide ranged from 30 to 290 mg/L. Twinkling on cholesterol crystals increased by 70% and 140% when oxygen and carbon dioxide levels were maximized, respectively. In contrast, twinkling on calcium phosphate and uric acid was not significantly affected by either gas. These results suggest that changes in twinkling from increased gas concentrations are dependent on crystal composition and are likely affected by biological adaptations in vivo. [Work supported by NSF-CAREER-1943937 and NSF-GRFP-DGE1255832.]