Interferometric speckle visibility spectroscopy (ISVS) for human cerebral blood flow monitoring
Abstract
Infrared light scattering methods have been developed and employed to non-invasively monitor human cerebral blood flow (CBF). However, the number of reflected photons that interact with the brain is low when detecting blood flow in deep tissue. To tackle this photon-starved problem, we present and demonstrate the idea of interferometric speckle visibility spectroscopy (ISVS). In ISVS, an interferometric detection scheme is used to boost the weak signal light. The blood flow dynamics are inferred from the speckle statistics of a single frame speckle pattern. We experimentally demonstrated the improvement in the measurement of fidelity by introducing interferometric detection when the signal photon number is low. We apply the ISVS system to monitor the human CBF in situations where the light intensity is ∼100-fold less than that in common diffuse correlation spectroscopy (DCS) implementations. Due to the large number of pixels (∼2 × 10⁵) used to capture light in the ISVS system, we are able to collect a similar number of photons within one exposure time as in normal DCS implementations. Our system operates at a sampling rate of 100 Hz. At the exposure time of 2 ms, the average signal photoelectron number is ∼0.95 count/pixel, yielding a single pixel interferometric measurement signal-to-noise ratio (SNR) of ∼0.97. The total ∼2 × 10⁵ pixels provide an expected overall SNR of 436. We successfully demonstrate that the ISVS system is able to monitor the human brain pulsatile blood flow, as well as the blood flow change when a human subject is doing a breath-holding task.
Additional Information
© 2020 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). Submitted: 16 July 2020 • Accepted: 19 November 2020 • Published Online: 4 December 2020. The authors would like to thank Professor John O'Doherty, Professor Adoph Ralphs, Dr. Yan Liu, Dr. Haowen Ruan, and Dr. Haojiang Zhou for their helpful discussions. This research was supported by Kernel-Brain Research and Technologies—Grant No. FS 13520230. AUTHORS' CONTRIBUTIONS. J.X., A.K.J., and J.B. contributed equally to this work. DATA AVAILABILITY. The data that support the findings of this study are available from the corresponding author upon reasonable request.Errata
Jian Xu, Ali K. Jahromi, Joshua Brake, J. Elliott Robinson, and Changhuei Yang , "Erratum: "Interferometric speckle visibility spectroscopy (ISVS) for human cerebral blood flow monitoring" [APL Photonics 5, 126102 (2020)]", APL Photonics 7, 059902 (2022) https://doi.org/10.1063/5.0096266Attached Files
Published - 5.0021988.pdf
Supplemental Material - isvs_for_human_cbf_monitoring_revision_supp.pdf
Erratum - 5.0096266.pdf
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Additional details
- Eprint ID
- 106963
- Resolver ID
- CaltechAUTHORS:20201208-105038376
- Kernel-Brain Research and Technologies
- FS 13520230
- Created
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2020-12-09Created from EPrint's datestamp field
- Updated
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2022-05-12Created from EPrint's last_modified field