1. Quantitative hemodynamic imaging: a method to correct the effects of optical properties on laser speckle imaging
- Author
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Phan, Thinh, Crouzet, Christian, Kennedy, Gordon T, Durkin, Anthony J, and Choi, Bernard
- Subjects
Engineering ,Biomedical Engineering ,Bioengineering ,Neurosciences ,Neurological ,cerebral hemodynamics ,diffuse optics ,laser speckle imaging ,spatial frequency domain imaging ,tissue optics ,Medical Biotechnology ,Biomedical engineering - Abstract
SignificanceStudying cerebral hemodynamics may provide diagnostic information on neurological conditions. Wide-field imaging techniques, such as laser speckle imaging (LSI) and optical intrinsic signal imaging, are commonly used to study cerebral hemodynamics. However, they often do not account appropriately for the optical properties of the brain that can vary among subjects and even during a single measurement. Here, we describe the combination of LSI and spatial-frequency domain imaging (SFDI) into a wide-field quantitative hemodynamic imaging (QHI) system that can correct the effects of optical properties on LSI measurements to achieve a quantitative measurement of cerebral blood flow (CBF).AimWe describe the design, fabrication, and testing of QHI.ApproachThe QHI hardware combines LSI and SFDI with spatial and temporal synchronization. We characterized system sensitivity, accuracy, and precision with tissue-mimicking phantoms. With SFDI optical property measurements, we describe a method derived from dynamic light scattering to obtain absolute CBF values from LSI and SFDI measurements. We illustrate the potential benefits of absolute CBF measurements in resting-state and dynamic experiments.ResultsQHI achieved a 50-Hz raw acquisition frame rate with a 10×10 mm field of view and flow sensitivity up to ∼4 mm/s. The extracted SFDI optical properties agreed well with a commercial system (R2≥0.98). The system showed high stability with low coefficients of variations over multiple sessions within the same day (
- Published
- 2023