Evaluation of hyperspectral NIRS for quantitative measurements of tissue oxygen saturation by comparison to time-resolved NIRS

Kewin, Matthew; Rajaram, Ajay; Milej, Daniel; Abdalmalak, Androu; Morrison, Laura; Diop, Mamadou; Lawrence, Keith St.

doi:10.1364/boe.10.004789

Cited by 19 publications

(14 citation statements)

References 37 publications

(50 reference statements)

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“…The performance of the algorithm could be improved by an optimization of wavelengths, perhaps extending the range to capture HbO 2 features at 670 nm. The effect of wavelength selection in our broadband measurements is evident when comparing the results obtained with BF in other literature; the error of recovering StO 2 in Monte Carlo simulated data [ 28 ] was approximately four times smaller than the error of StO 2 recovery in model 1, Fig. 3 .…”

Section: Discussionsupporting

confidence: 60%

“…BRUNO is a hybrid algorithm based on two other oximetry algorithms; a broadband approach based on differential spectroscopy, further referred to as ‘broadband fitting’ (BF), and spatially resolved spectroscopy (SRS), a multidistance approach relying on a measurement of the attenuation slope to quantify scaled absorption and then StO 2 . BF [ 27 ] has been evaluated in Monte Carlo studies and compared to time-resolved (TR) NIRS measurements [ 28 ]; it has also been applied in preterm infants [ 29 ]. SRS, on the other hand, has been developed in the mid-1990s [ 30 ] and is used commercially in NIRO devices (Hamamatsu Photonics, Japan) [ 31 ] and in research instruments [ 32 , 33 ].…”

Section: Introductionmentioning

confidence: 99%

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Absolute quantification of cerebral tissue oxygen saturation with multidistance broadband NIRS in newborn brain

Kovacsova¹,

Bale²,

Mitra³

et al. 2021

Biomed. Opt. Express

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Tissue oximetry with near-infrared spectroscopy (NIRS) is a technique for the measurement of absolute tissue oxygen saturation (StO 2 ). Offering a real-time and non-invasive assessment of brain oxygenation and haemodynamics, StO 2 has potential to be used for the assessment of newborn brain injury. Multiple algorithms have been developed to measure StO 2 , however, issues with low measurement accuracy or extracranial tissue signal contamination remain. In this work, we present a novel algorithm to recover StO 2 in the neonate, broadband multidistance oximetry (BRUNO), based on a measurement of the gradient of attenuation against distance measured with broadband NIRS. The performance of the algorithm was compared to two other published algorithms, broadband fitting (BF) and spatially resolved spectroscopy (SRS). The median error when recovering StO 2 in light transport simulations on a neonatal head mesh was 0.4% with BRUNO, 4.2% with BF and 9.5% with SRS. BRUNO was more sensitive to brain tissue oxygenation changes, shown in layered head model simulations. Comparison of algorithm performance during full oxygenation-deoxygenation cycles in a homogeneous dynamic blood phantom showed significant differences in the dynamic range of the algorithms; BRUNO recovered StO 2 over 0–100%, BF over 0–90% and SRS over 39–80%. Recovering StO 2 from data collected in a neonate treated at the neonatal intensive care showed different baseline values; mean StO 2 was 64.9% with BRUNO, 67.2% with BF and 73.2% with SRS. These findings highlight the effect of StO 2 algorithm selection on oxygenation recovery; applying BRUNO in the clinical care setting could reveal further insight into complex haemodynamic processes occurring during neonatal brain injury.

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Section: Discussionsupporting

confidence: 60%

Section: Introductionmentioning

confidence: 99%

Absolute quantification of cerebral tissue oxygen saturation with multidistance broadband NIRS in newborn brain

Kovacsova¹,

Bale²,

Mitra³

et al. 2021

Biomed. Opt. Express

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“…Data were collected using an in-house built TR-fNIRS system (Milej et al, 2016b;Kewin et al, 2019). The system consisted of two lasers (λ = 760 and 830 nm) pulsing at 80 MHz and controlled by a Sepia laser driver (PicoQuant, Germany).…”

Section: Tr-nirs Systemmentioning

confidence: 99%

Assessing Time-Resolved fNIRS for Brain-Computer Interface Applications of Mental Communication

et al. 2020

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Brain-computer interfaces (BCIs) are becoming increasingly popular as a tool to improve the quality of life of patients with disabilities. Recently, time-resolved functional nearinfrared spectroscopy (TR-fNIRS) based BCIs are gaining traction because of their enhanced depth sensitivity leading to lower signal contamination from the extracerebral layers. This study presents the first account of TR-fNIRS based BCI for "mental communication" on healthy participants. Twenty-one (21) participants were recruited and were repeatedly asked a series of questions where they were instructed to imagine playing tennis for "yes" and to stay relaxed for "no." The change in the mean timeof-flight of photons was used to calculate the change in concentrations of oxy-and deoxyhemoglobin since it provides a good compromise between depth sensitivity and signal-to-noise ratio. Features were extracted from the average oxyhemoglobin signals to classify them as "yes" or "no" responses. Linear-discriminant analysis (LDA) and support vector machine (SVM) classifiers were used to classify the responses using the leave-one-out cross-validation method. The overall accuracies achieved for all participants were 75% and 76%, using LDA and SVM, respectively. The results also reveal that there is no significant difference in accuracy between questions. In addition, physiological parameters [heart rate (HR) and mean arterial pressure (MAP)] were recorded on seven of the 21 participants during motor imagery (MI) and rest to investigate changes in these parameters between conditions. No significant difference in these parameters was found between conditions. These findings suggest that TR-fNIRS could be suitable as a BCI for patients with brain injuries.

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“…This study presents an in-house built brain monitoring system referred to as NNeMo (Neonatal NeuroMonitor) that is capable of simultaneous measurement of cerebral perfusion, tissue saturation, and oxygen metabolism at the bedside through combining two optical techniques. Broadband near-infrared spectroscopy (B-NIRS) uses near-infrared light to measure absorption properties of tissue that can be used to estimate the concentrations of oxy and deoxyhemoglobin, from which the cerebral tissue saturation (S t O 2 ) can be calculated [21]. B-NIRS can also provide a direct measurement of cerebral metabolism by monitoring absorption changes in the oxidation state of cytochrome c oxidase (oxCCO), which is directly related to mitochondrial ATP production in the electron transport chain [22].…”

Section: Introductionmentioning

confidence: 99%

Perfusion and Metabolic Neuromonitoring during Ventricular Taps in Infants with Post-Hemorrhagic Ventricular Dilatation

et al. 2020

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Post-hemorrhagic ventricular dilatation (PHVD) is characterized by a build-up of cerebral spinal fluid (CSF) in the ventricles, which increases intracranial pressure and compresses brain tissue. Clinical interventions (i.e., ventricular taps, VT) work to mitigate these complications through CSF drainage; however, the timing of these procedures remains imprecise. This study presents Neonatal NeuroMonitor (NNeMo), a portable optical device that combines broadband near-infrared spectroscopy (B-NIRS) and diffuse correlation spectroscopy (DCS) to provide simultaneous assessments of cerebral blood flow (CBF), tissue saturation (StO2), and the oxidation state of cytochrome c oxidase (oxCCO). In this study, NNeMo was used to monitor cerebral hemodynamics and metabolism in PHVD patients selected for a VT. Across multiple VTs in four patients, no significant changes were found in any of the three parameters: CBF increased by 14.6 ± 37.6% (p = 0.09), StO2 by 1.9 ± 4.9% (p = 0.2), and oxCCO by 0.4 ± 0.6 µM (p = 0.09). However, removing outliers resulted in significant, but small, increases in CBF (6.0 ± 7.7%) and oxCCO (0.1 ± 0.1 µM). The results of this study demonstrate NNeMo’s ability to provide safe, non-invasive measurements of cerebral perfusion and metabolism for neuromonitoring applications in the neonatal intensive care unit.

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Evaluation of hyperspectral NIRS for quantitative measurements of tissue oxygen saturation by comparison to time-resolved NIRS

Cited by 19 publications

References 37 publications

Absolute quantification of cerebral tissue oxygen saturation with multidistance broadband NIRS in newborn brain

Absolute quantification of cerebral tissue oxygen saturation with multidistance broadband NIRS in newborn brain

Assessing Time-Resolved fNIRS for Brain-Computer Interface Applications of Mental Communication

Perfusion and Metabolic Neuromonitoring during Ventricular Taps in Infants with Post-Hemorrhagic Ventricular Dilatation

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