A Hybrid Multi-Distance Phase and Broadband Spatially Resolved Algorithm for Resolving Absolute Concentrations of Chromophores in the Near-Infrared Light Spectrum: Results from Studies in Dynamic Phantoms

Tachtsidis, Ilias; Leung, Terence S.; Tahir, Bilal; Elwell, Clare E.; Kohl‐Bareis, Matthias; Gramer, Markus; Cooper, Chris E.

doi:10.1364/biomed.2008.bsue76

Cited by 6 publications

(7 citation statements)

References 5 publications

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“…Devices and methods using this fNIRI multi-spectral (or broadband) approach are under development (e.g. Diop et al, 2009;Pucci et al, 2010;Srinivasan et al, 2007;Tachtsidis et al, 2008bTachtsidis et al, , 2011Tachtsidis et al, , 2012Xu et al, 2005). That the usage of the different spectral fitting methods has an effect on the measured concentration changes has been shown by Schelkanova and Toronov (2010).…”

Section: Three and More Wavelengthsmentioning

confidence: 99%

A review on continuous wave functional near-infrared spectroscopy and imaging instrumentation and methodology

Scholkmann¹,

Kleiser²,

Metz³

et al. 2014

NeuroImage

1,523

1,394

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This year marks the 20th anniversary of functional near-infrared spectroscopy and imaging (fNIRS/fNIRI). As the vast majority of commercial instruments developed until now are based on continuous wave technology, the aim of this publication is to review the current state of instrumentation and methodology of continuous wave fNIRI. For this purpose we provide an overview of the commercially available instruments and address instrumental aspects such as light sources, detectors and sensor arrangements. Methodological aspects, algorithms to calculate the concentrations of oxy-and deoxyhemoglobin and approaches for data analysis are also reviewed. From the single-location measurements of the early years, instrumentation has progressed to imaging initially in two dimensions (topography) and then three (tomography). The methods of analysis have also changed tremendously, from the simple modified Beer-Lambert law to sophisticated image reconstruction and data analysis methods used today. Due to these advances, fNIRI has become a modality that is widely used in neuroscience research and several manufacturers provide commercial instrumentation. It seems likely that fNIRI will become a clinical tool in the foreseeable future, which will enable diagnosis in single subjects. This year marks the 20th anniversary of functional near-infrared spectroscopy and imaging (fNIRS/fNIRI). As the vast majority of commercial instruments developed until now are based on continuous wave technology, the aim of this publication is to review the current state of instrumentation and methodology of continuous wave fNIRI. For this purpose we provide an overview of the commercially available instruments and address instrumental aspects such as light sources, detectors and sensor arrangements. Methodological aspects, algorithms to calculate the concentrations of oxy-and deoxyhemoglobin and approaches for data analysis are also reviewed. From the single-location measurements of the early years, instrumentation has progressed to imaging initially in two dimensions (topography) and then three (tomography). The methods of analysis have also changed tremendously, from the simple modified Beer-Lambert law to sophisticated image reconstruction and data analysis methods used today. Due to these advances, fNIRI has become a modality that is widely used in neuroscience research and several manufacturers provide commercial instrumentation. It seems likely that fNIRI will become a clinical tool in the foreseeable future, which will enable diagnosis in single subjects. Contents

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Section: Three and More Wavelengthsmentioning

confidence: 99%

A review on continuous wave functional near-infrared spectroscopy and imaging instrumentation and methodology

Scholkmann¹,

Kleiser²,

Metz³

et al. 2014

NeuroImage

1,523

1,394

View full text Add to dashboard Cite

show abstract

“…Absolute values of chromophores are essential in studies where comparisons between patient data are required or when the knowledge of the baseline of the chromophore concentration is needed [5]. Time-resolved NIRS techniques, such as fdNIRS, provide a good compromise between simplicity of instrument design, low cost and portability of cwNIRS techniques and the accuracy and high information content of expensive time-domain NIRS instruments [1], [2], [5]- [7].…”

Section: Introductionmentioning

confidence: 99%

“…Time-resolved NIRS techniques, such as fdNIRS, provide a good compromise between simplicity of instrument design, low cost and portability of cwNIRS techniques and the accuracy and high information content of expensive time-domain NIRS instruments [1], [2], [5]- [7]. This paper presents a CMOS sensor chip integrating a low noise front-end circuit and signal processing electronics for high-resolution amplitude and phase measurement of RF modulated optical signals for fdNIRS studies.…”

Section: Introductionmentioning

confidence: 99%

A CMOS Sensor for Measurement of Cerebral Optical Coefficients Using Non-Invasive Frequency Domain Near Infrared Spectroscopy

Koomson

2013

IEEE Sensors J.

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A heterodyned architecture is integrated with a 180 nm CMOS chip for use in portable frequency domain near infrared spectroscopy (fdNIRS) tools for real time monitoring of tissue oxygenation in the brain. The design and performance measurement results of this chip are summarized in this paper to demonstrate its applicability in multi-distance fdNIRS to measure the absorption and scattering coefficients of tissue. The 2.25 mm 2 chip is integrated with four sensor channels, which have a high frequency low noise front end and information processing circuitry to interface with an avalanche photodiode to detect the high speed weak light signal. The four-channel sensor draws 40 mA of current from a 1.8 V power supply and uses an offchip counter implemented on an FPGA to quantify the amplitude and phase information required for tissue characterization with < 6.5% and < 2.5% linearity error, respectively. An experiment using the multi-distance measurement is used to measure the optical properties of a homogeneous tissue phantom using the CMOS integrated instrument.Index Terms-Frequency domain near infrared spectroscopy, CMOS, transimpedance amplifier, amplitude and phase detection, amplifier noise, optical sensor.

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“…In an attempt to address these issues, we have recently developed a hybrid optical spectrometer comprising a novel combination of broadband and frequency-domain near-infrared systems. The hybrid optical spectrometer has been described in detail elsewhere but, in brief, comprises two identical broadband spectroscopy systems and a two-channel frequency-domain spectrometer capable of absolute measurement of optical absorption and scattering at 690, 750, 790 and 850 nm over two regions of interest [57].…”

Section: (C) Monitoring Cerebral Autoregulation After Brain Injurymentioning

confidence: 99%

Shedding light on the adult brain: a review of the clinical applications of near-infrared spectroscopy

Smith

2011

Phil. Trans. R. Soc. A.

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Near-infrared spectroscopy (NIRS) has potential as a non-invasive brain monitor in a wide range of clinical scenarios. In the last decade, there has been a rapid expansion of clinical experience using NIRS to monitor cerebral oxygenation, particularly in cardiac surgery, where there is some evidence that NIRS-guided brain protection protocols might lead to a reduction in peri-operative neurological complications. There are no data to support the wider application of NIRS to monitor cerebral oxygenation during routine anaesthesia and surgery, and its application in brain injury, where it might be expected to have a key monitoring role, is as yet undefined. Technological developments, including the introduction of broadband and time-resolved spectrometers that are capable of reliably measuring changes in oxidized cytochrome c oxidase, offer real potential for a single NIRS-based device to provide multi-site, regional monitoring of cerebral metabolic status as well as oxygenation and haemodynamics.

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A Hybrid Multi-Distance Phase and Broadband Spatially Resolved Algorithm for Resolving Absolute Concentrations of Chromophores in the Near-Infrared Light Spectrum: Results from Studies in Dynamic Phantoms

Cited by 6 publications

References 5 publications

A review on continuous wave functional near-infrared spectroscopy and imaging instrumentation and methodology

A review on continuous wave functional near-infrared spectroscopy and imaging instrumentation and methodology

A CMOS Sensor for Measurement of Cerebral Optical Coefficients Using Non-Invasive Frequency Domain Near Infrared Spectroscopy

Shedding light on the adult brain: a review of the clinical applications of near-infrared spectroscopy

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