Design of photoacoustic modular helmet for neonatal neurocritical care

Perinatal arterial ischemic stroke (PAIS) is a form of focal vascular neurological injury that occurs during or shortly after birth. We recently proposed a modular PA helmet (PAH) system, in which multiple modules constitutes a flexible helmet to accommodate any neonatal head shape and size to provide volumetric monitoring of neonatal brain oxygen saturation. Here, optical tracking of the PAH configuration enables spatial image reconstruction. Given the large freedom in PAH configuration, it is critical to understand the implications of various design parameters in imaging quality. In this paper, we present our simulation-aided design approach using acoustic and optical simulation tools. Our design criteria are to optimize 1) signal contrast and 2) spatial resolution with different number of modules and their mean distances, and is further challenged with modular position error inevitable in modular position recognition. Results of the simulation established an acceptable error threshold for optical tracking and informed module prototype configuration and shape. The prototype based on the optimal design specifications is also demonstrated.