Interferometric diffusing wave spectroscopy imaging with an electronically variable time-of-flight filter

Zhao, Mingjun; Zhou, Wenjun; Aparanji, Santosh; Mazumder, Dibbyan; Srinivasan, Vivek J.

doi:10.1364/optica.472471

Cited by 18 publications

(12 citation statements)

References 72 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…9 (R s ¼ 0.57, p ¼ 0.121; R s ¼ 0.38, p ¼ 0.313; R s ¼ 0.28, p ¼ 0.463 for the homogenous, two-layer, and three-layer models, respectively). Finally, we point out that hematocrit varied across the cohort (median [IQR] of 34 [27,36] %). Because hematocrit can significantly confound DCS measurements, 24 the correlation between DCS and TCD may further improve with the development of validated approaches to correct DCS for hematocrit.…”

Section: Discussionmentioning

confidence: 99%

Comparison of diffuse correlation spectroscopy analytical models for measuring cerebral blood flow in adults

Zhao,

Sathialingam,

Cowdrick

et al. 2023

J. Biomed. Opt.

View full text Add to dashboard Cite

.SignificanceAlthough multilayer analytical models have been proposed to enhance brain sensitivity of diffuse correlation spectroscopy (DCS) measurements of cerebral blood flow, the traditional homogeneous model remains dominant in clinical applications. Rigorous in vivo comparison of these analytical models is lacking.AimWe compare the performance of different analytical models to estimate a cerebral blood flow index (CBFi) with DCS in adults.ApproachResting-state data were obtained on a cohort of 20 adult patients with subarachnoid hemorrhage. Data at 1 and 2.5 cm source-detector separations were analyzed with the homogenous, two-layer, and three-layer models to estimate scalp blood flow index and CBFi. The performance of each model was quantified via fitting convergence, fit stability, brain-to-scalp flow ratio (BSR), and correlation with transcranial Doppler ultrasound (TCD) measurements of cerebral blood flow velocity in the middle cerebral artery (MCA).ResultsThe homogeneous model has the highest pass rate (100%), lowest coefficient of variation (CV) at rest (median [IQR] at 1 Hz of 0.18 [0.13, 0.22]), and most significant correlation with MCA blood flow velocities (Rs = 0.59, p = 0.010) compared with both the two- and three-layer models. The multilayer model pass rate was significantly correlated with extracerebral layer thicknesses. Discarding datasets with non-physiological BSRs increased the correlation between DCS measured CBFi and TCD measured MCA velocities for all models.ConclusionsWe found that the homogeneous model has the highest pass rate, lowest CV at rest, and most significant correlation with MCA blood flow velocities. Results from the multilayer models should be taken with caution because they suffer from lower pass rates and higher coefficients of variation at rest and can converge to non-physiological values for CBFi. Future work is needed to validate these models in vivo, and novel approaches are merited to improve the performance of the multimodel models.

show abstract

Section: Discussionmentioning

confidence: 99%

Comparison of diffuse correlation spectroscopy analytical models for measuring cerebral blood flow in adults

Zhao,

Sathialingam,

Cowdrick

et al. 2023

J. Biomed. Opt.

View full text Add to dashboard Cite

show abstract

“…For SCOS, the implementation model was based on 850 nm operation with a CMOS camera with pixel number, read noise, and quantum efficiency properties based on aggregated camera properties for commercially available cameras 35 . Although great success has recently been shown in the application of interferometric methods to both SCOS and DCS, 14 , 15 , 36 – 41 we restricted the analysis in this work to strictly homodyne methods. The photon flux at each simulated source–detector separation was estimated from the diffuse reflectance output from MMC and scaling the results based on estimates from previous studies 42 .…”

Section: Methodsmentioning

confidence: 99%

Comparing the performance potential of speckle contrast optical spectroscopy and diffuse correlation spectroscopy for cerebral blood flow monitoring using Monte Carlo simulations in realistic head geometries

Robinson,

Cheng,

Renna

et al. 2024

Neurophoton.

View full text Add to dashboard Cite

The non-invasive measurement of cerebral blood flow based on diffuse optical techniques has seen increased interest as a research tool for cerebral perfusion monitoring in critical care and functional brain imaging. Diffuse correlation spectroscopy (DCS) and speckle contrast optical spectroscopy (SCOS) are two such techniques that measure complementary aspects of the fluctuating intensity signal, with DCS quantifying the temporal fluctuations of the signal and SCOS quantifying the spatial blurring of a speckle pattern. With the increasing interest in the use of these techniques, a thorough comparison would inform new adopters of the benefits of each technique.Aim: We systematically evaluate the performance of DCS and SCOS for the measurement of cerebral blood flow.Approach: Monte Carlo simulations of dynamic light scattering in an MRI-derived head model were performed. For both DCS and SCOS, estimates of sensitivity to cerebral blood flow changes, coefficient of variation of the measured blood flow, and the contrast-to-noise ratio of the measurement to the cerebral perfusion signal were calculated. By varying complementary aspects of data collection between the two methods, we investigated the performance benefits of different measurement strategies, including altering the number of modes per optical detector, the integration time/fitting time of the speckle measurement, and the laser source delivery strategy.Results: Through comparison across these metrics with simulated detectors having realistic noise properties, we determine several guiding principles for the optimization of these techniques and report the performance comparison between the two over a range of measurement properties and tissue geometries. We find that SCOS outperforms DCS in terms of contrast-to-noise ratio for the cerebral blood flow signal in the ideal case simulated here but note that SCOS requires careful experimental calibrations to ensure accurate measurements of cerebral blood flow. Conclusion:We provide design principles by which to evaluate the development of DCS and SCOS systems for their use in the measurement of cerebral blood flow.

show abstract

“…In biological applications, DWS has been used to assess brain activity [439,440], to monitor blood flow [441] and the visual cortex [442] and cerebral blood flows [443]. Diffusing-wave spectroscopy can be performed with interferometric detection using long coherence [444,445] or short coherence to resolve optical path length [434,[446][447][448][449] as well as with swept-source for coherence control [450] and with holographic detection [399,451].…”

Section: Diffusing Wave Spectroscopy (Dws) and Diffuse-correlation Sp...mentioning

confidence: 99%

Coherent light scattering from cellular dynamics in living tissues

Nolte

2024

Rep. Prog. Phys.

View full text Add to dashboard Cite

This review examines the biological physics of intracellular transport probed by the coherent optics of dynamic light scattering from optically thick living tissues. Cells and their constituents are in constant motion, composed of a broad range of speeds spanning many orders of magnitude that reflect the wide array of functions and mechanisms that maintain cellular health. From the organelle scale of tens of nanometers and upward in size, the motion inside living tissue is actively driven rather than thermal, propelled by the hydrolysis of bioenergetic molecules and the forces of molecular motors. Active transport can mimic the random walks of thermal Brownian motion, but mean-squared displacements are far from thermal equilibrium and can display anomalous diffusion through Lévy or fractional Brownian walks. Despite the average isotropic three-dimensional environment of cells and tissues, active cellular or intracellular transport of single light-scattering objects is often pseudo-one-dimensional, for instance as organelle displacement persists along cytoskeletal tracks or as membranes displace along the normal to cell surfaces, albeit isotropically oriented in three dimensions. Coherent light scattering is a natural tool to characterize such tissue dynamics because persistent directed transport induces Doppler shifts in the scattered light. The many frequency-shifted partial waves from the complex and dynamic media interfere to produce dynamic speckle that reveals tissue-scale processes through speckle contrast imaging and fluctuation spectroscopy. Low-coherence interferometry, dynamic optical coherence tomography, diffusing-wave spectroscopy, diffuse-correlation spectroscopy, differential dynamic microscopy and digital holography offer coherent detection methods that shed light on intracellular processes. In health-care applications, altered states of cellular health and disease display altered cellular motions that imprint on the statistical fluctuations of the scattered light. For instance, the efficacy of medical therapeutics can be monitored by measuring the changes they induce in the Doppler spectra of living ex vivo cancer biopsies.

show abstract

Interferometric diffusing wave spectroscopy imaging with an electronically variable time-of-flight filter

Cited by 18 publications

References 72 publications

Comparison of diffuse correlation spectroscopy analytical models for measuring cerebral blood flow in adults

Comparison of diffuse correlation spectroscopy analytical models for measuring cerebral blood flow in adults

Comparing the performance potential of speckle contrast optical spectroscopy and diffuse correlation spectroscopy for cerebral blood flow monitoring using Monte Carlo simulations in realistic head geometries

Coherent light scattering from cellular dynamics in living tissues

Contact Info

Product

Resources

About