Photoacoustic Neuroimaging - Perspectives on a Maturing Imaging Technique and its Applications in Neuroscience

Abstract

A prominent goal of neuroscience is to improve our understanding of how brain structure and activity interact to produce perception, emotion, behavior, and cognition. The brain’s network activity is inherently organized in distinct spatiotemporal patterns that span scales from nanometer-sized synapses to meter-long nerve fibers and millisecond intervals between electrical signals to decades of memory storage. There is currently no single imaging method that alone can provide all the relevant information, but intelligent combinations of complementary techniques can be effective. Here, we thus present the latest advances in biomedical and biological engineering on photoacoustic neuroimaging in the context of complementary imaging techniques. A particular focus is placed on recent advances in whole-brain photoacoustic imaging in rodent models and its influential role in bridging the gap between fluorescence microscopy and more non-invasive techniques such as magnetic resonance imaging (MRI). We consider current strategies to address persistent challenges, particularly in developing molecular contrast agents, and conclude with an overview of potential future directions for photoacoustic neuroimaging to provide deeper insights into healthy and pathological brain processes.

Broadband Model‐Based Optoacoustic Mesoscopy Enables Deep‐Tissue Imaging beyond the Acoustic Diffraction Limit

“…[ 8 ] On the other hand, OA is gaining maturity as a neuroimaging tool. [ 80 ] High‐resolution imaging of cortical vascular networks can provide new insights into cerebrovascular function in health and disease. [ 20 ] Regarding potential clinical applications, OAM may provide new solutions to unmet clinical needs.…”

“…A third simulation was performed to validate the capability of MB-L1 to accurately quantify micro-vessel dimensions. To this end, OA signals corresponding to truncated paraboloid absorbers with diameters of (20,30,45,60,80 A fifth simulation was performed to confirm the super-resolution imaging capability of the MB-L1 method. For this, complex structures mimicking vascular networks with two different densities were simulated.…”

Photoacoustic Imaging in Biomedicine and Life Sciences

“…Photo-acoustic imaging (PA or PAI) is based upon the generation of rapid thermoelastic expansion and contraction within soft biological tissues through incident laser pulses. This localised thermal expansion leads to the subsequent emission of ultrasonic waves, which are then reconstructed in two or more dimensions to portray the internal spatial distribution of optical absorption [1][2][3][4][5][6][7][8][9][10][11]. Experiencing much less scattering compared to conventional optical techniques, PAI propagates deeper into biological tissues and provides higher spatial imaging resolution compared to conventional optical imaging techniques for high scattering objects, thereby breaking through the optical diffusion limit ultrasonically [12].…”

Advancing photoacoustic tomography using deep learning

“…IH is an established medical phenomenon caused due to the depletion of CSF, as CSF pressure is the modulating factor for intracranial pressure [42,43]. For inducing the IH, the CSF leak was mimicked by extracting the CSF from the cisterna magna, the most easily accessible subarachnoid space opening in adult rats.…”

“…All these advantages have led to a rapid development of PAI over the last two decades. Furthermore, the potential of PAI has also been explored for numerous applications such as breast cancer imaging [38], brain imaging [39], eye imaging [40,41], neuro imaging [42,43], tumor imaging [44][45][46], vascular imaging [47,48], sentinel lymph node mapping [49,50], small animal whole-body imaging [51,52], gastrointestinal imaging [53], drug delivery monitoring [54] etc. For brevity, PAT/PACT will be referred to as PAT here on wards.…”