PROJECT SUMMARY/ABSTRACT
The lack of a noninvasive, cost-effective, and highly accessible technology for monitoring cerebral metabolic rate
of oxygen (CMRO2) poses a critical gap in neurology and brain health. Current methods, including positron
emission tomography, functional magnetic resonance imaging, diffuse optical tomography, and catheter-based
jugular venous oxygen saturation monitoring, have limitations such as radiation exposure, invasiveness, limited
spatial and temporal resolution, and reduced accessibility. This project aims to address this unmet need by
developing the next-generation photoacoustic computed tomography through an ergodic relay (PACTER) device
for noninvasive CMRO2 monitoring. In Aim 1, the device will be designed and fabricated to enable high-resolution
vascular imaging of oxygen metabolism. This will involve integrating an acoustic impedance-matching layer,
using longer-wavelength illumination for improved spatial resolution and penetration depth for imaging the carotid
artery and internal jugular vein, and employing dual-wavelength illumination for quantifying total hemoglobin
concentration and oxygen saturation. Additionally, blood flow will be measured using photoacoustic vector
tomography. The device will be customized for handheld operation, ensuring easy access to imaging regions. In
Aim 2, the next-generation PACTER device will be characterized and validated for monitoring CMRO2 in humans.
Imaging performance, accuracy, and sensitivity will be assessed using tissue-simulating phantoms, animal
models, healthy volunteers, and patients with neurological conditions. By measuring relevant parameters in the
carotid artery and internal jugular vein, including blood volume, hemoglobin concentration, oxygen saturation,
and blood flow, the device will enable the calculation of oxygen extraction and CMRO2. Comparisons with
existing methods, such as fMRI, will be conducted, setting the stage for future clinical validation studies. The
proposed research addresses the significant gap in noninvasive CMRO2 monitoring and offers transformative
advancements. The development of the next-generation PACTER device will facilitate personalized diagnostics
and care for neurology, neurosurgery, and critical care patients. It will provide timely and crucial information for
accurate diagnosis, treatment guidance, and surgical decision-making, ultimately leading to improved medical
outcomes and quality of life. Furthermore, the cost-effectiveness and accessibility of PACTER will contribute to
reducing the overall cost of medical care and benefit researchers in the field. The project's innovation lies in the
creation of a highly accessible device with label-free, non-ionizing, and high-spatiotemporal-resolution imaging
capabilities, overcoming the limitations of current CMRO2 monitoring techniques. In summary, the next-
generation PACTER device offers a novel approach to noninvasive CMRO2 monitoring, addressing a critical gap
in the field. This research will facilitate progress towards significant improvements in brain health assessment,
personalized diagnostics, and intraoperative monitoring, ultimately advancing our understanding of brain function
and improving patient outcomes.