Possible role of ultrasound research platforms in measuring endogenous decompression bubble nuclei

Venous gas emboli (VGE), of the order of several tens of micrometers, can be detected with ultrasound imaging after scuba diving and are a marker of physiological decompression stress. Higher VGE post-dive are associated with a higher risk of decompression sickness, but these bubbles can also be observed after shallow, conservative and completely asymptomatic dives. The risk of decompression sickness, but also the amount of VGE observed post-dive, have been shown to exhibit a significant amount of yet unexplained inter- and intra-subject variability, even for an identical, controlled diving exposure. Importantly, the precise location and formation mechanism of VGE both remain largely unknown. In this talk, we describe the development of ultrasound techniques that overcome barriers to effective imaging of these bubbles in humans. A focus is on optimizing the assessment of post-dive bubble loads by refining their evaluation on echocardiograms to facilitate a more dynamic assessment. Emphasis will then be given to the adaptation of biomedical ultrasound contrast-specific imaging schemes to investigate the infamous "micronuclei" hypothesized to be at the origin of the gas bubbles observed in divers.