Spectrometer calibration for spectroscopic Fourier domain optical coherence tomography

Szkulmowski, Maciej; Tamborski, Szymon; Wojtkowski, Maciej

doi:10.1364/boe.7.005042

Cited by 29 publications

(27 citation statements)

References 39 publications

(57 reference statements)

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“…Dispersion mismatch between the two arms was first carefully compensated with N-SF11 compensation glass (Edmund Optics), and the small residual mismatch was then finely corrected with a numerical compensation technique. 23 The axial resolution, defined as the full-width half-maximum, was measured to be 2 pixels on the tomogram, which is equivalent to about 8.3 μm in biological tissues, and its lateral resolution in tissue was about 2.3 μm. In the sample arm, a dichroic filter was placed to transmit the infrared light used by OCT system and deflect the visible light for wide-field imaging.…”

Section: Spectral-domain Oct Imaging Systemmentioning

confidence: 99%

Longitudinal optical coherence tomography imaging of tissue repair and microvasculature regeneration and function after targeted cerebral ischemia

Zhang

et al. 2020

J. Biomed. Opt.

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Significance: Understanding how the brain recovers from cerebral tissue and vascular damage after an ischemic event can help develop new therapeutic strategies for the treatment of stroke. Aim: We investigated cerebral tissue repair and microvasculature regeneration and function after a targeted ischemic stroke. Approach: Following photothrombosis occlusion of microvasculature, chronic optical coherence tomography (OCT)-based angiography was used to track ischemic tissue repair and microvasculature regeneration at three different cortical depths and up to 28 days in awake animals. Capillary network orientation analysis was performed to study the structural pattern of newly formed microvasculature. Based on the time-resolved OCT-angiography, we also investigated capillary stalling, which is likely related to ischemic stroke-induced inflammation. Results: Deeper cerebral tissue was found to have a larger ischemic area than shallower regions at any time point during the course of poststroke recovery, which suggests that cerebral tissue located deep in the cortex is more vulnerable. Regenerated microvasculature had a highly organized pattern at all cortical depths with a higher degree of structural reorganization in deeper regions. Additionally, capillary stalling event analysis revealed that cerebral ischemia augmented stalling events considerably. Conclusion: Longitudinal OCT angiography reveals that regenerated capillary network has a highly directional pattern and an increased density and incidence of capillary stalling event.

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Section: Spectral-domain Oct Imaging Systemmentioning

confidence: 99%

Longitudinal optical coherence tomography imaging of tissue repair and microvasculature regeneration and function after targeted cerebral ischemia

Zhang

et al. 2020

J. Biomed. Opt.

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“…The spectral interferogram was registered by a spectrometer (Cobra 1300-[1235-1385 nm], Wasatch Photonics, USA) and then digitized by a frame grabber (PCIe-1433, National Instruments, USA). Dispersion mismatch between the two arms was first carefully compensated with N-SF11 compensation glass (Edmund Optics, USA), and the small residual mismatch was then finely corrected with a numerical compensation technique 34 . The axial resolution was measured to be about 4.15 µm in biological tissues.…”

Section: Oct Acquisition Systemmentioning

confidence: 99%

A Simulation Study Investigating Potential Diffusion-based MRI Signatures of Microstrokes

Damseh

et al. 2020

Preprint

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Recent studies suggested that cerebrovascular micro-occlusions , i.e. microstokes, could lead to ischemic tissue infarctions and cognitive deficits. Due to their small size, identifying measurable biomarkers of these microvascular lesions remains a major challenge. This work aims to simulate potential MRI signatures combining arterial spin labeling (ASL) and multi-directional diffusion-weighted imaging (DWI). Driving our hypothesis are recent observations demonstrating a radial reorientation of microvasculature around the micro-infarction locus during recovery in mice. Synthetic capillary beds, randomly- and radially- oriented, and optical coherence tomography (OCT) angiograms, acquired in the barrel cortex of mice (n=5) before and after inducing targeted photothrombosis, were analyzed. Computational vascular graphs combined with a 3D Monte-Carlo simulator were used to characterize the magnetic resonance (MR) response, encompassing the effects of magnetic field perturbations caused by deoxyhemoglobin, and the advection and diffusion of the nuclear spins. We quantified the minimal intravoxel signal loss ratio when applying multiple gradient directions, at varying sequence parameters with and without ASL. With ASL, our results demonstrate a significant difference (p<0.05) between the signal-ratios computed at baseline and 3 weeks after photothrombosis. The statistical power further increased (p<0.005) using angiograms measured at week 4. Without ASL, no reliable signal change was found. We found that higher ratios, and accordingly improved significance, were achieved at lower magnetic field strengths (e.g., B0=3) and shorter readout TE (<16 ms). Our simulations suggest that microstrokes might be characterized through ASL-DWI sequence, providing necessary insights for posterior experimental validations, and ultimately, future translational trials.

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“…Changes in systematic polarizations or spectrally uneven back-coupling efficiencies might affect the calibration result. In a similar approach, a calibration scheme can utilize the Doppler frequency shifts produced by controlled mirror motions which are independent of the systematic dispersion mismatches [13,14]. This method can be interpreted as a dynamic variant of the double measurement scheme of K. Wang et al's.…”

Section: A Spectrometer Calibrationmentioning

confidence: 99%

“…From the ideal fringe form, the spectrometer could be calibrated to correct the spectral OCT signals to be later acquired. Note that a grating-based spectrometer used widely as a signal acquisition means for an SD-OCT system does not detect the signals in a correctly registered manner in frequency or wavenumber (denoted by k, hereafter) [5][6][7][8][9][10][11][12][13][14][15][16]. It needs an accurate calibration for so-called linear-k resampling.…”

Section: Introductionmentioning

confidence: 99%

Characterization of spectral-domain OCT with autocorrelation interference response for axial resolution performance

Moon¹,

Qu²,

Chen³

2018

Opt. Express

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We present a class of novel system characterization methods for spectral-domain optical coherence tomography (SD-OCT) particularly on getting optimized axial resolution performance. Our schemes uniquely utilize the autocorrelation interference response, also known as the self-interference product, which is generated by the optical fields from the imaging sample in automatic interferences. In our methods, an autocorrelation-inducing calibration sample was prepared which was made by sandwiching glass plates. OCT images of the calibration sample were captured by an SD-OCT system under testing. And the image data were processed to find various system characteristics based on the unique properties of autocorrelation interferograms, free of dispersion- and polarization-involved modulations. First, we could analyze the sampling characteristic of the SD-OCT's spectrometer for spectral calibration that enables accurate linear-k resampling of detected spectral fringes. Second, we could obtain the systematic polarization properties for quantifying their impact on the achieved axial resolutions. We found that our methods based on the autocorrelation response provide an easy way of self-characterization and self-validation that is useful in optimizing and maintaining axial resolution performances. It was found very attractive that a variety of system characteristics can be obtained in a single-shot measurement without any increased system complexity.

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Spectrometer calibration for spectroscopic Fourier domain optical coherence tomography

Cited by 29 publications

References 39 publications

Longitudinal optical coherence tomography imaging of tissue repair and microvasculature regeneration and function after targeted cerebral ischemia

Longitudinal optical coherence tomography imaging of tissue repair and microvasculature regeneration and function after targeted cerebral ischemia

A Simulation Study Investigating Potential Diffusion-based MRI Signatures of Microstrokes

Characterization of spectral-domain OCT with autocorrelation interference response for axial resolution performance

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