Extendable, large-field multi-modal optical imaging system for measuring tissue hemodynamics

Wang, Chen; Chen, Xiao; Hong, Jiachi; Meng, Liangwei; Cheng, Weimin; Zhu, Xuan; Lu, Jinling; Li, Pengcheng

doi:10.1364/boe.386197

Cited by 5 publications

(2 citation statements)

References 40 publications

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“…10 Considering its temporal and spatial resolution, LSCI could reveal static blood vessel structure and dynamic cerebral blood flow (CBF). Several researchers have used LSCI to observe microvasculature structure, for example, in the retina, [11][12][13][14] cerebral cortex, 15,16 skin surface, 17,18 ear, 17 and other in vivo tissues. 19 Others used LSCI to characterize BFA, for instance, sensory activation, 20 somatosensory (S1BF) activation, 5,21,22 and auditory activation.…”

Section: The Application Of Lsci To Study Brain Structure and Functionmentioning

confidence: 99%

Analysis and visualization methods for detecting functional activation using laser speckle contrast imaging

Niu

Yang

et al. 2022

Microcirculation

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Background: Previous studies have used regional cerebral blood flow (CBF) hemodynamic response to measure brain activities. In this work, we use a laser speckle contrast imaging (LSCI) apparatus to sample the CBF activation in somatosensory cortex (S1BF) with repetitive whisker stimulation. Traditionally, the CBF activations were processed by depicting the change percentage above baseline; however, it is not clear how different methods influence the detection of activations.Aims: Thus, in this work we investigate the influence of different methods to detect activations in LSCI. Materials & Methods: First, principal component analysis (PCA) was performed to denoise the CBF signal. As the signal of the first principal component (PC1) showed the highest correlation with the S1BF CBF response curve, PC1 was used in the subsequent analyses. Then, we used fast Fourier transform (FFT) to evaluate the frequency properties of the LSCI images and the activation map was generated based on the amplitude of the central frequency. Furthermore, Pearson's correlation coefficient (C-C) analysis and a general linear model (GLM) were performed to estimate the S1BF activation based on the time series of PC1.Results: We found that GLM performed better in identifying activation than C-C.Additionally, the activation maps generated by FFT were similar to those obtained by GLM. Particularly, the superficial vein and arterial vessels separated the activation region as segmented activated areas, and the regions with unresolved vessels showed a common activation for whisker stimulation. Discussion and Conclusion:Our research analyzed the extent to which PCA can extract meaningful information from the signal and we compared the performance for detecting brain functional activation between different methods that rely on LSCI. This can be used as a reference for LSCI researchers on choosing the best method to estimate brain activation.

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Section: The Application Of Lsci To Study Brain Structure and Functionmentioning

confidence: 99%

Analysis and visualization methods for detecting functional activation using laser speckle contrast imaging

Niu

Yang

et al. 2022

Microcirculation

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“…Other groups have adopted an integration approach that directly uses the LED emission spectra during calculations. 23 – 26 This method requires careful characterization of the system LEDs and is more appropriate for nb-DRS.…”

Section: Introductionmentioning

confidence: 99%

Spectral correction of light emitting diodes enables accurate hydration ratio calculation using narrowband diffuse reflectance spectroscopy

Lam

Kim

et al. 2023

J. Biomed. Opt.

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. Significance Light emitting diodes (LEDs) are commonly utilized for tissue spectroscopy due to their small size, low cost, and simplicity. However, LEDs are often approximated as single-wavelength devices despite having relatively broad spectral bandwidths. When paired with photodiodes, the wavelength information of detected light cannot be resolved. This can result in errors during chromophore concentration calculations. These errors are particularly apparent when analyzing water and fat in the 900 to 1000 nm window where the spectral bandwidth of LEDs can encompass much of the analysis region, resulting in intense crosstalk. Aim We utilize and present a spectral correction (SC) algorithm to correct for the spectral bandwidth of LEDs. We show the efficacy using a narrowband technique of spectrally broad and overlapping LEDs. Approach Narrowband diffuse reflectance spectroscopy (nb-DRS), a technique capable of quantifying the hydration ratio ( ) of turbid media, was utilized. nb-DRS typically requires a broadband light source and spectrometer. We reduce the hardware to just five LEDs and a photodiode detector, relying on SC to compensate for spectral crosstalk. The effectiveness of our SC approach was tested in simulations as well as in an emulsion phantom and limited selection of human tissue. Results In simulations, we show that calculated errors increased with the spectral bandwidth of LEDs but could be corrected using SC. Likewise, in emulsions, we found an average error of 8.7% (maximum error 14%) if SC was not used. By contrast, applying SC reduced the average error to 2.2% (maximum error of 6.4%). We show that despite utilizing multiple, spectrally broad, and overlapping LEDs, SC was still able to restore the performance of our narrowband method, making it comparable to a much larger full broadband system.

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Motion correction of laser speckle imaging of blood flow by simultaneous imaging of tissue structure and non-rigid registration

Xiao-hu

Wei

Meng

et al. 2021

Optics and Lasers in Engineering

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Extendable, large-field multi-modal optical imaging system for measuring tissue hemodynamics

Cited by 5 publications

References 40 publications

Analysis and visualization methods for detecting functional activation using laser speckle contrast imaging

Analysis and visualization methods for detecting functional activation using laser speckle contrast imaging

Spectral correction of light emitting diodes enables accurate hydration ratio calculation using narrowband diffuse reflectance spectroscopy

Motion correction of laser speckle imaging of blood flow by simultaneous imaging of tissue structure and non-rigid registration

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