2026-06-02 テキサス大学オースチン校（UT Austin）
＜関連情報＞
- https://news.utexas.edu/2026/06/02/newly-discovered-view-of-brain-blood-flow-during-surgery-could-prevent-debilitation-save-lives/
- https://www.pnas.org/doi/abs/10.1073/pnas.2524940123
強度変調による長時間露光を用いた高速組織ダイナミクスのマッピング Mapping fast tissue dynamics with long camera exposures via intensity modulation
Hengfa Lu, Qingwei Fang, Jewel A. Ashbrook, +3 , and Andrew K. Dunn
Proceedings of the National Academy of Sciences Published:April 23, 2026
DOI:https://doi.org/10.1073/pnas.2524940123
Significance
Characterizing fast biological dynamics, such as blood flow in the brain’s microvasculature, across wide fields is crucial but typically demands expensive, specialized high-speed cameras. We address this limitation with sinusoidal intensity modulation speckle imaging (SIMSI), which encodes rapid dynamics within a long camera exposure. By decoupling the effective measurement timescale from frame rate, SIMSI captures microsecond to millisecond dynamics using standard cameras. Sweeping the modulation frequency yields wide field maps of the fluctuation spectrum, enabling frequency-resolved characterization of tissue dynamics. We validate SIMSI measurements with a coaligned high-speed reference detector and demonstrate utility by tracking cerebrovascular changes for ten days after stroke. This accessible method for wide field spectral mapping opens avenues for studying disease, materials, and complex fluids.
Abstract
Measuring fast dynamic processes with dynamic light scattering over wide fields of view is critical for applications ranging from blood flow imaging to characterizing complex fluids, yet is often limited by the need for expensive, high frame rate cameras. Here, we introduce sinusoidal intensity modulation speckle imaging (SIMSI), a technique that overcomes this hardware limitation by encoding information about fast dynamics into images captured with long camera exposures. Within each exposure, we sinusoidally modulate the illumination intensity, yielding frequency selective speckle variance measurements that sample the power spectral density (PSD) of intensity fluctuations. By sweeping the modulation frequency across exposures, SIMSI maps the PSD while preserving high signal-to-noise long exposures. We fit the measured spectra with a flexible model and report a spectral cutoff frequency fc as a flow index. In controlled flow microfluidic phantoms, SIMSI PSD estimates agree with the reference PSD measurements from a coaligned high-speed detector, and the derived fc varies linearly with the imposed flow velocity (R2>0.999). In vivo in the mouse cortex, the SIMSI derived fc maps distinguish vascular compartments with distinct spectral signatures. Finally, SIMSI tracks the spatiotemporal evolution of cortical blood flow changes for ten days following ischemic stroke. SIMSI provides a robust and accessible method for wide field, frequency domain characterization of fast dynamics using standard cameras. This advance enables a richer characterization of complex systems and has wide ranging applications in biomedicine, engineering, and physics.
