Noninvasive real time tomographic imaging of epileptic foci and networks

Abstract

While brain imaging and electrophysiology play a central role in neuroscience research and in the evaluation of neurological disorders, a single noninvasive modality that offers both high spatial and temporal resolution is currently not available. Here we show in an acute epilepsy rat model that photoacoustic tomography (PAT) can noninvasively track seizure brain dynamics with both high spatial and temporal resolution, and at a depth that is clinically relevant. The noninvasive yet whole surface and depth capabilities of the PAT system allowed us to actually see what is happening during ictogenesis in terms of seizure onset and spread. Both seizure onset and propagation were tomographically detected at a spatial resolution of 150μm and a temporal resolution of 300ms, respectively. The current study lends support to the theory that seizure onset and spread involves a rich interplay between multiple cortical and subcortical brain areas during the onset and spread of epileptic seizures. Dynamical changes of vasculature during epileptiform events were also detected with high spatiotemporal resolution. Together, these findings suggest that PAT represents a powerful tool for noninvasively mapping seizure onset and propagation patterns, and the 'functional' connectivity within epileptic brain networks.