# Time-Gated Diffuse Correlation Spectroscopy for functional imaging of the human brain

> **NIH NIH U01** · MASSACHUSETTS GENERAL HOSPITAL · 2020 · $1,418,720

## Abstract

Project Summary/Abstract
Functional near-infrared spectroscopy (fNIRS) is a well-established neuroimaging method which enables
neuroscientists to study brain activity by non-invasively monitoring hemodynamic changes in the cerebral cortex.
In the last decade, the use of fNIRS has increased significantly with the formation of a society, with an exponential
growth of users and publications, and with an increasing number of available commercial instruments. Despite
these successes, the impact of fNIRS as a neuroimaging method could be greatly enhanced by addressing
several technological limitations.
In line with the BRAIN Initiative RFA EB-17-004 “Development of Next Generation Human Brain Imaging Tools
and Technologies” we propose to develop completely novel methodology to measure human brain function,
time-gated functional diffuse correlation spectroscopy (fDCS), which will dramatically improve upon the
capabilities of fNIRS. DCS, a cutting-edge optical modality, quantifies relative blood flow changes (rCBF) by
measuring the light intensity temporal fluctuations generated by the dynamic scattering of light by moving red
blood cells. A few years ago, we demonstrated the ability to operate DCS in the time-domain, and supported by
the parent early stage RFA EB-17-001, developed the first portable time-gated fDCS system. With this device
we can discriminate late from early arriving photon, obtaining blood flow measures only from photons which have
travelled deeper into the tissue, further increasing sensitivity to brain.
Our established team, which includes investigators from Massachusetts General Hospital, Massachusetts
Institute of Technology Lincoln Laboratory, and Boston University, is now ready to make a leap forward in this
technology with the goal to offer an imaging system that covers the whole adult head while producing high
resolution images of functional blood flow changes with 2-3x improvements in contrast to noise ratio, brain
sensitivity and resistance to extracerebral physiology cross-talk. This goal will be achieved by: i) using a longer
wavelength, specifically 1064 nm, where a multitude of factors combine to offer a 10x increase in light throughput,
as well as lower scattering for increased penetration depth and spatial resolution; ii) developing new laser and
detectors with optimal specifications for time-gated fDCS, overcoming limitations of current commercially
available components; iii) scaling-up the new components to build a multichannel system and an high density
fiber optic cap with 96 sources and 192 detectors distributed in a hexagonal pattern with an ~13mm separation,
for a total of 576 channels, to produce high resolution images of functional blood flow changes. The novel time-
gated fDCS system will be characterized in tissue-like phantoms, and validated in healthy volunteers during
standard functional tasks, against continuous-wave NIRS, DCS and fMRI.
The development of this technology will provide an unprecedented tool...

## Key facts

- **NIH application ID:** 10022331
- **Project number:** 5U01EB028660-02
- **Recipient organization:** MASSACHUSETTS GENERAL HOSPITAL
- **Principal Investigator:** Maria Angela Franceschini
- **Activity code:** U01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $1,418,720
- **Award type:** 5
- **Project period:** 2019-09-21 → 2024-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10022331

## Citation

> US National Institutes of Health, RePORTER application 10022331, Time-Gated Diffuse Correlation Spectroscopy for functional imaging of the human brain (5U01EB028660-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10022331. Licensed CC0.

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