# Massively parallel high-speed 3D functional photoacoustic computed tomography of the adult human brain

> **NIH NIH U01** · CALIFORNIA INSTITUTE OF TECHNOLOGY · 2024 · $1,239,362

## Abstract

ABSTRACT (30 Lines)
The BRAIN initiative (RFA-EB-19-002) has called for the development of entirely new or next-generation
noninvasive human brain imaging tools and methods that will lead to transformative advances in our
understanding of the human brain. Functional MRI (fMRI) at ultrahigh fields has made tremendous improvements
in spatiotemporal resolution, allowing brain function to be studied on the level of cortical layers and columns.
However, fMRI is generally considered to have a low sensitivity and strong tissue background for detection of
function. Positron emission tomography provides powerful metabolic imaging through radioactive tracers but
suffers low spatial resolution, as is diffuse optical tomography despite its advantages in speed, cost, and
portability. Ultrasound-only imaging cannot image adult human brains because the ultrasonic waves are
attenuated and aberrated twice by the skull due to the round-trip propagation.
 To address these issues, we propose to develop 3D photoacoustic computed tomography (PACT) for fast
and ultrafast large-scale neural activity imaging in human brains. PACT is especially well suited for detecting
hemodynamic changes related to neural activities. It offers comparable spatial resolution but can be made much
faster than fMRI. It is directly sensitive to both oxy- and deoxy-hemoglobin linearly with a low tissue background.
Other potential benefits of PACT over fMRI include open imaging platforms, minimal site requirements, quiet and
bedside operation, magnet-free environment, and low system maintenance.
 In the last two decades, we have developed photoacoustic technology at multiple spatial scales ranging from
microscopic (subcellular and cellular) to macroscopic (whole rodent, whole human breast, ex vivo adult human
skull, and preliminary single-channel 2D and 64-channel 3D in vivo adult human brain) imaging. We have
revealed hemodynamic response in the rodent brain to whisker or electrical stimulation and mapped the resting-
state functional connectivity of the rat brain in the deep thalamic region. We have also developed sophisticated
numerical methods for simulating photoacoustic wave propagation in heterogeneous media and developed
frameworks for image reconstruction in acoustically heterogeneous media. Further, we have successfully
demonstrated ex vivo PACT through adult human skulls and acquired preliminary images of human heads in
vivo. We propose to translate these advances in PACT to human brain imaging through two specific aims:
Aim 1: Develop massively parallel high-speed 3D PACT for in vivo fast and ultrafast functional human brain
imaging.
Aim 2: Validate functional PACT in adult humans in vivo by comparing with ultrahigh-field 7 T fMRI.

## Key facts

- **NIH application ID:** 10906090
- **Project number:** 5U01EB029823-05
- **Recipient organization:** CALIFORNIA INSTITUTE OF TECHNOLOGY
- **Principal Investigator:** Danny JJ WANG
- **Activity code:** U01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $1,239,362
- **Award type:** 5
- **Project period:** 2020-09-08 → 2026-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10906090

## Citation

> US National Institutes of Health, RePORTER application 10906090, Massively parallel high-speed 3D functional photoacoustic computed tomography of the adult human brain (5U01EB029823-05). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10906090. Licensed CC0.

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