scholarly journals Ambulant monitoring of bladder oxygenation and hemodynamics using wireless near-infrared spectroscopy

2013 ◽  
Vol 7 (1-2) ◽  
pp. 98 ◽  
Author(s):  
Andrew John Macnab ◽  
Babak Shadgan ◽  
Lynn Stothers ◽  
Kourosh Afshar
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Symphysis Pubis ◽  
Bladder Volume ◽  
Lower Urinary Tract Dysfunction ◽  
Detrusor Muscle ◽  
Silicon Photodiode ◽  
Nirs Data ◽  
Asymptomatic Subjects

Introduction: Near-infrared spectroscopy (NIRS) non-invasively detects changes in the concentration of the chromophores oxygenated (ΔO2Hb) and deoxygenated hemoglobin (ΔHHb) as the bladder detrusor muscle contracts during voiding. Such data provide novel information on bladder oxygenation and hemodynamics. We evaluated the feasibility of monitoring ambulant subjects using a wireless NIRS device.Methods: The wireless device uses paired light-emitting diodes (wavelengths 760 and 850 nm) and a silicon photodiode detector. We monitored 14 asymptomatic subjects (10 adults, 4 children) and 6 symptomatic children with non-neurogenic lower urinary tract dysfunction (NLUTD) during spontaneous voiding after natural filling. The device was taped to the abdominal skin 2 cm above the symphysis pubis across the midline. The wireless NIRS data (patterns of change in chromophore concentration) were compared between subjects and to the data obtained using a laser-powered instrument.Results: Graphs of ΔO2Hb, ΔHHb and total hemoglobin (ΔtHb) were obtained from all 20 patients. Data during uroflow showed reproducible patterns of bladder chromophore change between asymptomatic subjects (rise in ΔtHb/ΔO2Hb), consistent with laser instrument data. In contrast, all 6 symptomatic children had a negative trend in ΔtHb, with falls in ΔO2Hb. One adult experienced “shy” bladder and changes in hemodynamics/oxygenation occurred while bladder volume was unchanged.Conclusions: Wireless NIRS bladder monitoring is feasible in ambulant adults and children; wireless and laser-derived data in asymptomaticsubjects are comparable. Pilot data suggest that subjects with symptomatic NLUTD have impaired bladder oxygenation/hemodynamics. The fact that chromophore changes occur when bladder volume remains constant supports the concept that NIRS data are a physiologic measure.

scholarly journals Near-Infrared Spectroscopy of the Bladder: New Parameters for Evaluating Voiding Dysfunction

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Andrew Macnab ◽  
Babak Shadgan ◽  
Kourosh Afshar ◽  
Lynn Stothers
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Voiding Dysfunction ◽  
Outlet Obstruction ◽  
Positive Trend ◽  
Healthy Children ◽  
Silicon Photodiode ◽  
Light Emitting ◽  
Chromophore Concentration

We describe innovative methodology for monitoring alterations in bladder oxygenation and haemodynamics in humans using near-infrared spectroscopy (NIRS). Concentrations of the chromophores oxygenated (O2Hb) and deoxygenated (HHb) haemoglobin and their sum (total haemoglobin) differ during bladder contraction in health and disease. A wireless device that incorporates three paired light emitting diodes (wavelengths 760 and 850 nanometers) and silicon photodiode detector collects data transcutaneously (10 Hz) with the emitter/detector over the bladder during spontaneous bladder emptying. Data analysis indicates comparable patterns of change in chromophore concentration in healthy children and adults (positive trend during voiding, predominantly due to elevated O2Hb), but different changes in symptomatic subjects with characteristic chromophore patterns identified for voiding dysfunction due to specific pathophysiologies: bladder outlet obstruction (males), overactive bladder (females), and nonneurogenic dysfunction (children). Comparison with NIRS muscle data suggests altered bladder haemodynamics and/or oxygenation may underlie voiding dysfunction offering new insight into the causal physiology.

scholarly journals Algorithm construction methodology for diagnostic classification of near-infrared spectroscopy data

2011 ◽  
Vol 25 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Ramón Guevara ◽  
Lynn Stothers ◽  
Andrew Macnab
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Pelvic Floor Muscle ◽  
Classification And Regression Tree ◽  
Data Sets ◽  
Linear Discriminant ◽  
Cart Analysis ◽  
Chromophore Concentration ◽  
Nirs Data

Background: Near-infrared spectroscopy (NIRS) has recognized potential but limited application for non-invasive diagnostic evaluation. Data analysis methodology that reproducibly distinguishes between the presence or absence of physiologic abnormality could broaden clinical application of this optical technique.Methods: Sample data sets from simultaneous NIRS bladder monitoring and invasive urodynamic pressure-flow studies (UDS) are used to illustrate how a diagnostic algorithm is constructed using classification and regression tree (CART) analysis. Misclassification errors of CART and linear discriminant analysis (LDA) are computed and examples of other urological NIRS data likely amenable to CART analysis presented.Results: CART generated a clinically relevant classification algorithm (error 4%) using 46 data sets of changes in chromophore concentration composed of the whole time series without specifying features. LDA did not (error 16%). Using CART NIRS data provided comparable discriminant ability to the UDS diagnostic nomogram for the presence or absence of obstructive pathology (88% specificity, 84% precision). Pilot data examples from children with and without voiding dysfunction and women with mild or severe pelvic floor muscle dysfunction also show potentially diagnostic differences in chromophore concentration.Conclusions: CART analysis can likely be applied in other NIRS monitoring applications intended to classify patients into those with and without pathology.

Human calf microvascular compliance measured by near-infrared spectroscopy

2000 ◽  
Vol 88 (2) ◽  
pp. 369-372 ◽  
Author(s):  
T. Binzoni ◽  
V. Quaresima ◽  
M. Ferrari ◽  
E. Hiltbrand ◽  
P. Cerretelli
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Region Of Interest ◽  
Venous System ◽  
Vasomotor Response ◽  
Head Up Tilt ◽  
Nirs Data ◽  
The Subject ◽  
Human Calf

The purpose of this study is to develop a new method for the measurement in humans of the compliance of the microvascular superficial venous system of the lower limb by near-infrared spectroscopy (NIRS). This method is complementary to strain-gauge plethysmography, which does not allow compliance between deep and superficial venous or between venous and arterial compartments to be distinguished. In practice, hydrostatic pressure (P) changes were induced in a calf region of interest by head-up tilt of the subject from α = −10 to 75°. For P ≤ 24 mmHg, the measured compliance [0.086 ± 0.005 (SD) ml ⋅ l− 1 ⋅ mmHg− 1] based on NIRS data of total, deoxygenated, and oxygenated hemoglobin, reflects essentially that of the superficial venous system. For P ≥ 24 mmHg, no distinction can be made between arterial and venous volumes changes. However, by following the changes in oxy- and deoxyhemoglobin in the P range −16 to 100 mmHg, it appears to be possible to assess the characteristics of the vasomotor response of the arteriolar system.

scholarly journals Understanding near infrared spectroscopy and its application to skeletal muscle research

2019 ◽  
Vol 126 (5) ◽  
pp. 1360-1376 ◽  
Author(s):  
Thomas J. Barstow
Keyword(s):  
Skeletal Muscle ◽  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Oxygen Delivery ◽  
Near Infrared ◽  
Control Mechanisms ◽  
Oxygen Utilization ◽  
Muscle Research ◽  
Athletic Field ◽  
Nirs Data

Near infrared spectroscopy (NIRS) is a powerful noninvasive tool with which to study the matching of oxygen delivery to oxygen utilization and the number of new publications utilizing this technique has increased exponentially in the last 20 yr. By measuring the state of oxygenation of the primary heme compounds in skeletal muscle (hemoglobin and myoglobin), greater understanding of the underlying control mechanisms that couple perfusive and diffusive oxygen delivery to oxidative metabolism can be gained from the laboratory to the athletic field to the intensive care unit or emergency room. However, the field of NIRS has been complicated by the diversity of instrumentation, the inherent limitations of some of these technologies, the associated diversity of terminology, and a general lack of standardization of protocols. This Cores of Reproducibility in Physiology (CORP) will describe in basic but important detail the most common methodologies of NIRS, their strengths and limitations, and discuss some of the potential confounding factors that can affect the quality and reproducibility of NIRS data. Recommendations are provided to reduce the variability and errors in data collection, analysis, and interpretation. The goal of this CORP is to provide readers with a greater understanding of the methodology, limitations, and best practices so as to improve the reproducibility of NIRS research in skeletal muscle.

Near-Infrared Spectroscopy: A Tool for Diagnosing Necrotizing Enterocolitis at Onset of Symptoms in Preterm Neonates with Acute Gastrointestinal Symptoms?

2020 ◽  
Author(s):  
Julia Le Bouhellec ◽  
Olivier Prodhomme ◽  
Thibault Mura ◽  
Aurélien Jacquot ◽  
Clémentine Combes ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Necrotizing Enterocolitis ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Cerebral Oxygenation ◽  
Gastrointestinal Symptoms ◽  
Abdominal Distension ◽  
Tissue Oxygen Saturation ◽  
Preterm Neonates ◽  
Nirs Data

Abstract Objective In premature neonates, bloody stools and/or abdominal distension with feeding intolerance may be inaugural signs of necrotizing enterocolitis (NEC). We assessed the ability of near-infrared spectroscopy (NIRS) to distinguish those neonates with NEC soon after the occurrence of these symptoms. Study Design We prospectively collected NIRS measurements of abdominal and cerebral regional tissue oxygen saturation (r-SO2), with values masked by an opaque cover. Two physicians, blinded to the NIRS data, determined whether the gastrointestinal symptoms were related to NEC 10 days after symptom onset. Results Forty-five neonates with mean (standard deviation [SD]) gestational, birth weight and postnatal ages of 31 (3.9) weeks, 1,486 (794) g, and 18 (14) days were enrolled over 30 months. Gastrointestinal symptoms were related to NEC in 23 patients and associated with other causes in 22. Analysis of the 48 hours of monitoring revealed comparable abdominal r-SO2 and splanchnic-cerebral oxygenation ratio (SCOR) in patients with and without NEC (r-SO2: 47.3 [20.4] vs. 50.4 [17.8], p = 0.59, SCOR: 0.64 [0.26] vs. 0.69 [0.24], p = 0.51). Results were unchanged after NIRS analysis in 6-hour periods, and restriction of the analysis to severe NEC (i.e., grade 2 and 3, 57% of the NEC cases). Conclusion In this study, NIRS monitoring was unable to individualize NEC in premature infants with acute gastrointestinal symptoms.

scholarly journals Using a Portable Near-infrared Spectroscopy Device to Estimate The Second Ventilatory Threshold

2021 ◽  
Author(s):  
Víctor Rodrigo-Carranza ◽  
Fernando González-Mohíno ◽  
Anthony P. Turner ◽  
Sergio Rodriguez-Barbero ◽  
José María González-Ravé
Keyword(s):  
Infrared Spectroscopy ◽  
Gas Exchange ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Ventilatory Threshold ◽  
Maximum Heart Rate ◽  
Nirs Data ◽  
Trained Runners ◽  
Healthy Participants

AbstractA breakpoint in a portable near-infrared spectroscopy (NIRS) derived deoxygenated haemoglobin (deoxy[Hb]) signal during an incremental VO2max running test has been associated with the second ventilatory threshold (VT2) in healthy participants. Thus, the aim was to examine the association between this breakpoint (NIRS) and VT2 in well-trained runners. Gas exchange and NIRS data were collected during an incremental VO2max running test for 10 well-trained runners. The breakpoint calculated in oxygen saturation (StO2) and the VT2 were determined and compared in terms relative to %VO2max, absolute speed, VO2, and maximum heart rate (HRmax). There were no significant differences (p>0.05) between the breakpoint in StO2 and VT2 relative to %VO2max (87.00±6.14 and 88.28 ± 3.98 %), absolute speed (15.70±1.42 and 16.10±1.66 km·h−1), VO2 (53.71±15.17 and 54.66±15.57 ml·kg−1·min−1), and%HRmax (90.90±4.17 and 91.84±3.70%). There were large and significant correlations between instruments relative to%VO2max (r=0.68, p<0.05), absolute speed (r=0.86, p<0.001), VO2 (r=0.86, p<0.001), and %HRmax (r=0.69; p<0.05). A Bland and Altman analysis of agreement between instruments resulted in a mean difference of − 1.27±4.49%, −0.40±0.84 km·h−1,−0.90±3.07 ml·kg−1·min−1, and − 0.94±3.14 for %VO2max, absolute speed, VO2, and %HRmax, respectively. We conclude that a portable NIRS determination of the StO2 breakpoint is comparable with VT2 using gas exchange and therefore appropriate for use in determining exercise training above VT2 intensity. This is the first study to analyze the validity with the running mode using a NIRS portable device.

scholarly journals Development of the hyperspectral near infrared spectroscopy for monitoring tissue oxygen metabolism

2021 ◽  
Author(s):  
Reyhaneh Nosrati
Keyword(s):  
Signal Processing ◽  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Oxygen Metabolism ◽  
Processing Algorithm ◽  
Mathematical Concepts ◽  
Signal Processing Algorithm ◽  
Nirs Data ◽  
Series Of Experiments

Near Infrared Spectroscopy (NIRS) employs optical window of 650-1100 nm to measure the concentrations of different chromophores such as, oxygenated hemoglobin (HbO2), deoxygenated hemoglobin (Hb) and water. In addition, changes in the redox cytochrome c oxidase (Cyt-ox) can be measured using hyperspectral NIRS. Cyt-ox has a relatively low concentration compared to HbO2 and HHb therefore its measurements is very challenging. The main objective of this thesis was to identify the best signal-processing algorithm for deconvolution of the Cyt-ox changes. In this thesis two different studies have been done; in the first study, functional broadband NIRS during simulated driving (on 16 adult subjects) has been recorded and the best data processing algorithm for deconvolution of the chromophores was identified. In the second series of experiments broadband NIRS data during cardiac arrest and resuscitation was recorded on 19 pigs. A novel signal-processing algorithm was introduced to deconvolve Cyt-ox. The Introduction section covers relevant aspects of the theory and mathematical concepts. The Journal Manuscript part contains the two projects mentioned above. The last part is The Journal Manuscript part contains the two projects mentioned above. The last part is allocated for the overall conclusion of the entire thesis.

scholarly journals Classification Modeling Method for Near-Infrared Spectroscopy of Tobacco Based on Multimodal Convolution Neural Networks

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Lei Zhang ◽  
Xiangqian Ding ◽  
Ruichun Hou
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Infrared Spectroscopy ◽  
Convolutional Neural Network ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Two Dimensional ◽  
One Dimensional ◽  
Nirs Data ◽  
The One

The origin of tobacco is the most important factor in determining the style characteristics and intrinsic quality of tobacco. There are many applications for the identification of tobacco origin by near-infrared spectroscopy. In order to improve the accuracy of the tobacco origin classification, a near-infrared spectrum (NIRS) identification method based on multimodal convolutional neural networks (CNN) was proposed, taking advantage of the strong feature extraction ability of the CNN. Firstly, the one-dimensional convolutional neural network (1-D CNN) is used to extract and combine the pattern features of one-dimensional NIRS data, and then the extracted features are used for classification. Secondly, the one-dimensional NIRS data are converted into two-dimensional spectral images, and the structure features are extracted from two-dimensional spectral images by the two-dimensional convolutional neural network (2-D CNN) method. The classification is performed by the combination of global and local training features. Finally, the influences of different network structure parameters on model identification performance are studied, and the optimal CNN models are selected and compared. The multimodal NIR-CNN identification models of tobacco origin were established by using NIRS of 5,200 tobacco samples from 10 major tobacco producing provinces in China and 3 foreign countries. The classification accuracy of 1-D CNN and 2-D CNN models was 93.15% and 93.05%, respectively, which was better than the traditional PLS-DA method. The experimental results show that the application of 1-D CNN and 2-D CNN can accurately and reliably distinguish the NIRS data, and it can be developed into a new rapid identification method of tobacco origin, which has an important promotion value.

scholarly journals Near-Infrared Spectroscopy as a Beef Quality Tool to Predict Consumer Acceptance

Foods ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 984
Author(s):  
Wilson Barragán-Hernández ◽  
Liliana Mahecha-Ledesma ◽  
Joaquín Angulo-Arizala ◽  
Martha Olivera-Angel
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Structural Equation ◽  
Near Infrared ◽  
Likert Scale ◽  
Partial Least Square ◽  
Least Square ◽  
Equation Modeling ◽  
Nirs Data ◽  
Mean Square Errors

This study was conducted to evaluate the feasibility of using near-infrared spectroscopy (NIRS) to predict beef consumers’ perceptions. Photographs of 200 raw steaks were taken, and NIRS data were collected (transmittance and reflectance). The steak photographs were used to conduct a face-to-face survey of 400 beef consumers. Consumers rated beef color, visible fat, and overall appearance, using a 5-point Likert scale (where 1 indicated “Dislike very much” and 5 indicated “Like very much”), which later was simplified in a 3-point Likert scale. Factor analysis and structural equation modeling (SEM) were used to generate a beef consumer index. A partial least square discriminant analysis (PLS-DA) was used to predict beef consumers’ perceptions using NIRS data. SEM was used to validate the index, with root mean square errors of approximation ≤0.1 and comparative fit and Tucker–Lewis index values <0.9. PLS-DA results for the 5-point Likert scale showed low prediction (accuracy < 42%). A simplified 3-point Likert scale improved discrimination (accuracy between 52% and 55%). The PLS-DA model for purchasing decisions showed acceptable prediction results, particularly for transmittance NIRS (accuracy of 76%). Anticipating beef consumers’ willingness to purchase could allow the beef industry to improve products so that they meet consumers’ preferences.

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