Numerical investigation of cavitation inside the brain and correlation with injury

Blast-induced traumatic brain injury is prevalent in people involved in military combat. Cavitation is being hypothesized as a possible mechanism of primary injury of brain cells following exposure to a blast wave. Experimental investigations of laser-generated cavitation bubbles in a brain tissue surrogate have shown that the growth and collapse of the bubbles generate enough stretching in the medium to induce cell damage, and injury thresholds have been obtained. In this study, we provide a correlation between the observed stretching thresholds for various brain cells and the characteristics of the pressure pulse that would induce such thresholds. The range of values of the pulse we choose is in accordance with experimental results on blast propagation inside a brain surrogate. The pulse is input into our single bubble cavitation model, which consists of a modified Keller-Miksis equation that takes the medium viscoelastic behavior into account. We studied cavitation activity for a wide range of initial nucleus sizes and found that the injury threshold is predominant around 2 microns, which is consistent with previous results. With this critical nucleus size, we explore the space of the pulse parameters and relate cavitation to injury. These correlations will help determine safety limits against blast-induced traumatic injury.