Photoacoustic brain imaging: from microscopic to macroscopic scales

Abstract

Human brain mapping has become one of the most exciting contemporary research areas, with major breakthroughs expected in the following decades. Modern brain imaging techniques have allowed neuroscientists to gather a wealth of anatomic and functional information about the brain. Among these techniques, by virtue of its rich optical absorption contrast, high spatial and temporal resolutions, and deep penetration, photoacoustic tomography (PAT) has attracted more and more attention, and is playing an increasingly important role in brain studies. In particular, PAT complements other brain imaging modalities by providing high-resolution functional and metabolic imaging. More importantly, PAT’s unique scalability enables scrutinizing the brain at both microscopic and macroscopic scales, using the same imaging contrast. In this Review, we present the state-of-the-art PAT techniques for brain imaging, summarize representative neuroscience applications, outline the technical challenges in translating PAT to human brain imaging, and envision potential technological deliverables.

A practical guide to photoacoustic tomography in the life sciences

“…7a) 27 , metabolism of oxygen and glucose 74 , resting state connectivity 75 , and brain responses to various physiological and pathological challenges 76–78 . PAT can provide neuronal imaging using either endogenous contrast from lipids or exogenous contrast from dyes 79 . In addition, PAT has been increasingly used to study small-animal models of brain diseases, including stroke 80 , epilepsy 81 , and edema 60 .…”

Advances in Imaging Techniques and Genetically Encoded Probes for Photoacoustic Imaging

“…Deep-tissue PA imaging using genetically encoded reporter genes, particularly photoswitchable BphP1, offers a powerful tool for tracking cell fates and molecular functions in deep tissue within light-scattering living organisms. Although, unlike chemical dyes or nanoparticles, the use of BphP1 in humans remains challenging due to the requirement of introduction of exogenous genetic material 20 and potential safety issues 98, PA imaging with BphP1 provides unprecedented detection sensitivity and penetration depth and is thus useful for both basic research such as cancer, developmental biology and neurosciences and preclinical applications in small animals 10, 99, 100.…”

“…In general, there are four types of PA imaging systems 10: optical-resolution photoacoustic microscopy (OR-PAM), acoustic-resolution photoacoustic microscopy (AR-PAM), optical-resolution photoacoustic computed tomography (OR-PACT), and acoustic-resolution photoacoustic computed tomography (AR-PACT) (Figure 1). Depending on whether the laser beam or ultrasonic detection is more tightly focused, PA imaging can be divided into OR and AR with different lateral resolution.…”

Biomedical photoacoustics: fundamentals, instrumentation and perspectives on nanomedicine

“…96,97 A real-time and clear visualization of brain vasculature is of great importance to study its functions and diagnose developing diseases. Lu et al performed PEGylated conjugation with hollow gold nanospheres (PEG-HAuNS) as the contrast agent to show the brain vasculature of nude mice.…”