Assessing the Sensitivity of Multi-Distance Hyperspectral NIRS to Changes in the Oxidation State of Cytochrome C Oxidase in the Brain

Suwalski, Marianne; Shoemaker, Leena N.; Shoemaker, J. Kevin; Diop, Mamadou; Murkin, John M.; Chui, Jason; Lawrence, Keith St.; Milej, Daniel

doi:10.3390/metabo12090817

Cited by 13 publications

(14 citation statements)

References 56 publications

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“…DCS data were acquired using an in-house DCS system that included a continuous long coherence length (>10 m) emitting at 786 nm (DL852-100-SO, CrystaLaser, USA) [13]. The laser was coupled to a single fiber (core diameter 400 μm, NA = 0.22, Loptek, Germany).…”

Section: Instrumentationmentioning

confidence: 99%

Assessing extracerebral contamination in cerebral blood flow pulsatility measured by diffuse correlation spectroscopy

Mistry¹,

Shoemaker²,

Milej³

et al. 2023

Optical Tomography and Spectroscopy of Tissue XV

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Diffuse Correlation Spectroscopy (DCS) provides a non-invasive method of measuring microvasculature cerebral blood flow (CBF). Recent advancements have enabled flow pulsatility to be captured, providing a means of continuously monitoring critical closing pressure (CCP), which is intrinsically linked to intracranial pressure [1]. Similar to DCS measurements of mean CBF, DCS pulsatility data can be contaminated by blood flow in the extracerebral (EC) tissue [2]. This study focuses on extracting CBF pulsatility using the probe pressure modulation algorithm proposed by Baker et al. for removing EC contamination [3]. DCS data were collected from five healthy volunteers, along with continuous recordings of arterial blood pressure and ECG. Data were acquired at two source-detector distances (rSD = 1 and 2.5 cm) at a sampling frequency of 20 Hz [4]. The pulsatile waveform was generated by two methods: (1) fitting the semi-infinite model to data acquired at rSD = 2.5 cm and (2) applying the pressure modulation algorithm to data from both distances. The two waveforms were compared based on extracting waveform features, including the systolic-to-diastolic amplitude (YSD), reflective flow peak (S2), dicrotic notch (d), diastolic peak (D), and Δt (Δt = tS1 -td). Preliminary results indicated that removing EC contamination caused a significant increase in YSD and Δt. Reductions in S2 and d were also observed, but these changes did not reach statistical significance. In conclusion, these preliminary findings suggest that EC contamination can alter the shape of the pulsatile waveform, which could influence parameters such as CCP used to assess brain health. Collecting multi-distance DCS data and incorporating the pressure modulation algorithm to remove EC contamination is recommended.

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Section: Instrumentationmentioning

confidence: 99%

Assessing extracerebral contamination in cerebral blood flow pulsatility measured by diffuse correlation spectroscopy

Mistry¹,

Shoemaker²,

Milej³

et al. 2023

Optical Tomography and Spectroscopy of Tissue XV

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“…Measurements were acquired for 8 min (baseline) before deoxygenation of the solution in the bottom compartment by 2 g of yeast dissolved in 2 mL of 50% glucose and 1 mL of SBB. No yeast was added to the top layer compartment to mimic the low mitochondrial concentration in the ECL relative to the brain 25 , 63 . The bottom layer was left to deoxygenate for 28 min before reoxygenation was initiated by bubbling oxygen gas through the air stone.…”

Section: Methodsmentioning

confidence: 99%

“…Several studies have demonstrated that oxCCO can be monitored in piglets and neonates using CW systems; 5 , 7 , 24 however, extending the technique to adults has been hampered by contamination of brain-related signals by the thick adult extracerebral layers (ECL; scalp and skull) 6 , 25 , 26 . In adults, substantial light absorption and scattering occur in these surface layers, limiting light penetration into deeper tissues and reducing sensitivity to the brain 27 …”

Section: Introductionmentioning

confidence: 99%

“…16,[20][21][22][23] Several studies have demonstrated that oxCCO can be monitored in piglets and neonates using CW systems; 5,7,24 however, extending the technique to adults has been hampered by contamination of brain-related signals by the thick adult extracerebral layers (ECL; scalp and skull). 6,25,26 In adults, substantial light absorption and scattering occur in these surface layers, limiting light penetration into deeper tissues and reducing sensitivity to the brain. [27][28][29] Multidistance measurements have been proposed to account for the ECL contribution to the NIRS signal, 25,26,30,31 wherein the signal from a short source-detector distance is regressed from a long source-detector distance measurement.…”

mentioning

confidence: 99%

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HyperTRCSS: A hyperspectral time-resolved compressive sensing spectrometer for depth-sensitive monitoring of cytochrome-c-oxidase and blood oxygenation

Li,

Ioussoufovitch,

Diop

2024

J. Biomed. Opt.

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Hyperspectral time-resolved (TR) near-infrared spectroscopy offers the potential to monitor cytochrome-c-oxidase (oxCCO) and blood oxygenation in the adult brain with minimal scalp/skull contamination. We introduce a hyperspectral TR spectrometer that uses compressive sensing to minimize acquisition time without compromising spectral range or resolution and demonstrate oxCCO and blood oxygenation monitoring in deep tissue.Aim: Develop a hyperspectral TR compressive sensing spectrometer and use it to monitor oxCCO and blood oxygenation in deep tissue.Approach: Homogeneous tissue-mimicking phantom experiments were conducted to confirm the spectrometer's sensitivity to oxCCO and blood oxygenation. Twolayer phantoms were used to evaluate the spectrometer's sensitivity to oxCCO and blood oxygenation in the bottom layer through a 10 mm thick static top layer. Results:The spectrometer was sensitive to oxCCO and blood oxygenation changes in the bottom layer of the two-layer phantoms, as confirmed by concomitant measurements acquired directly from the bottom layer. Measures of oxCCO and blood oxygenation by the spectrometer were highly correlated with "gold standard" measures in the homogeneous and two-layer phantom experiments. Conclusions:The results show that the hyperspectral TR compressive sensing spectrometer is sensitive to changes in oxCCO and blood oxygenation in deep tissue through a thick static top layer.

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“…5 This work aimed to assess Kernel Flow's sensitivity to regional cerebral oxygenation changes using carotid compression (CC), a paradigm which results in substantial blood flow and oxyhemoglobin (HbO) reductions across the entire ipsilateral hemisphere. 6…”

Section: Introductionmentioning

confidence: 99%

Sensitivity of a full-head coverage high-density time-resolved NIRS device to carotid compressions

Kamar

Shoemaker

Abdalmalak³

et al. 2023

Optical Tomography and Spectroscopy of Tissue XV

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Neuromonitoring during cardiac surgery helps prevent brain injury by detecting evidence of cerebral ischemia. Current neuromonitoring devices, such as cerebral oximeters, generally monitor one brain region, which prevents the detection of blood flow impairment in other vascular territories. A potential solution is to use a device with full-head coverage such as the newly developed high-density time-resolved NIRS system, Kernel Flow. This work aimed to assess Kernel Flow's sensitivity to regional cerebral oxygenation changes using momentary carotid compression (CC), a paradigm that causes substantial decreases in cerebral blood flow and oxyhemoglobin (HbO) throughout the ipsilateral hemisphere. Five healthy volunteers were imaged using a Kernel Flow headset during a 30-s CC. To assess the sensitivity of the device to regional changes, the number of good quality channels was compared between four brain regions: frontal, somatosensory, temporal, and occipital. HbO and deoxyhemoglobin (HbR) time series in the ipsilateral and contralateral hemispheres were analyzed. Overall, the frontal region had the largest amount of good-quality channels, and the ipsilateral regions showed the expected HbO decrease during CC. All contralateral regions showed minimal changes during CC, as expected. Overall, the Flow device showed good sensitivity to reduced cerebral blood flow; however, its use as a neuromonitor during cardiac surgery could be challenged by signal degradation due to hair, although this may be less of an issue with cardiac patients considering that most are older and have less hair.

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Assessing the Sensitivity of Multi-Distance Hyperspectral NIRS to Changes in the Oxidation State of Cytochrome C Oxidase in the Brain

Cited by 13 publications

References 56 publications

Assessing extracerebral contamination in cerebral blood flow pulsatility measured by diffuse correlation spectroscopy

Assessing extracerebral contamination in cerebral blood flow pulsatility measured by diffuse correlation spectroscopy

HyperTRCSS: A hyperspectral time-resolved compressive sensing spectrometer for depth-sensitive monitoring of cytochrome-c-oxidase and blood oxygenation

Sensitivity of a full-head coverage high-density time-resolved NIRS device to carotid compressions

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