Real-time handheld probe tracking and image formation using digital frequency-domain diffuse optical spectroscopy

2021 ◽  
pp. 1-1
Author(s):  
Matthew Applegate ◽  
Robert Amelard ◽  
Carlos Gomez ◽  
Darren Roblyer
Keyword(s):  
Frequency Domain ◽  
Real Time ◽  
Optical Spectroscopy ◽  
Image Formation ◽  
Diffuse Optical Spectroscopy ◽  
Digital Frequency

Real-Time In Vivo Characterization of Primary Liver Tumors With Diffuse Optical Spectroscopy During Percutaneous Needle Interventions

2015 ◽  
Vol 50 (7) ◽  
pp. 443-448 ◽  
Author(s):  
Rami Nachabé ◽  
Benno H.W. Hendriks ◽  
Ross Schierling ◽  
Jasmine Hales ◽  
Judy M. Racadio ◽  
...  
Keyword(s):  
Real Time ◽  
Optical Spectroscopy ◽  
Liver Tumors ◽  
Diffuse Optical Spectroscopy ◽  
Primary Liver Tumors ◽  
In Vivo Characterization ◽  
Needle Interventions

scholarly journals Noninvasive in vivo monitoring of methemoglobin formation and reduction with broadband diffuse optical spectroscopy

2006 ◽  
Vol 100 (2) ◽  
pp. 615-622 ◽  
Author(s):  
Jangwoen Lee ◽  
Naglaa El-Abaddi ◽  
Andrew Duke ◽  
Albert E. Cerussi ◽  
Matthew Brenner ◽  
...  
Keyword(s):  
Real Time ◽  
Optical Spectroscopy ◽  
Near Infrared ◽  
Ex Vivo ◽  
Rabbit Model ◽  
Nir Spectroscopy ◽  
Blood Chemistry ◽  
Diffuse Optical Spectroscopy ◽  
Methemoglobin Formation

We present noninvasive, quantitative in vivo measurements of methemoglobin formation and reduction in a rabbit model using broadband diffuse optical spectroscopy (DOS). Broadband DOS combines multifrequency frequency-domain photon migration (FDPM) with time-independent near infrared (NIR) spectroscopy to quantitatively measure bulk tissue absorption and scattering spectra between 600 nm and 1,000 nm. Tissue concentrations (denoted by brackets) of methemoglobin ([MetHb]), deoxyhemoglobin ([Hb-R]), and oxyhemoglobin ([HbO2]) were determined from absorption spectra acquired in “real time” during nitrite infusions in nine pathogen-free New Zealand White rabbits. As little as 30 nM [MetHb] changes were detected for levels of [MetHb] that ranged from 0.80 to 5.72 μM, representing 2.2 to 14.9% of the total hemoglobin content (%MetHb). These values agreed well with on-site ex vivo cooximetry data ( r2 = 0.902, P < 0.0001, n = 4). The reduction of MetHb to functional hemoglobins was also carried out with intravenous injections of methylene blue (MB). As little as 10 nM changes in [MB] were detectable at levels of up to 150 nM in tissue. Our results demonstrate, for the first time, the ability of broadband DOS to noninvasively quantify real-time changes in [MetHb] and four additional chromophore concentrations ([Hb-R], [HbO2], [H2O], and [MB]) despite significant overlapping spectral features. These techniques are expected to be useful in evaluating dynamics of drug delivery and therapeutic efficacy in blood chemistry, human, and preclinical animal models.

Abstract 311: Selection of Optimal Predictor and Critical Thresholds for Return of Spontaneous Circulation Using Non-Invasive Frequency-Domain Diffuse Optical Spectroscopy During Cardiopulmonary Resuscitation

Circulation ◽  
2018 ◽  
Vol 138 (Suppl_2) ◽  
Author(s):  
Tiffany S Ko ◽  
Wensheng Guo ◽  
Constantine D Mavroudis ◽  
Ryan W Morgan ◽  
Wesley M Baker ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Optical Spectroscopy ◽  
Sensitivity Threshold ◽  
Invasive Monitoring ◽  
Diffuse Optical Spectroscopy ◽  
Absolute Change ◽  
Critical Thresholds ◽  
Non Invasive ◽  
The Mean ◽  
Over Time

Introduction: We have shown that during CPR, novel non-invasive monitoring of cerebral tissue oxygenation (StO 2 , %) and total hemoglobin concentration (THC, μmol/L) by frequency-domain diffuse optical spectroscopy (FD-DOS) is associated with ROSC in a swine model of pediatric cardiac arrest. Our objective is to find the optimal non-invasive predictor for ROSC and assess feasibility of a stable critical threshold over time in early CPR. Hypothesis: Stable critical thresholds with high sensitivity or specificity for ROSC may be established in early CPR (<10 min) from non-invasive cerebral StO 2 and THC measurements initiated at CPR start. Methods: One-month-old swine (n=31) underwent 7 minutes of asphyxia, induction of ventricular fibrillation, and up to 20 minutes of CPR till ROSC or death (no ROSC). Absolute StO 2 and THC and absolute and relative change from 1 minute into CPR (time for chest molding and FD-DOS placement) were evaluated as ROSC predictors over time. For each variable, an ROC curve and two critical thresholds, maximizing specificity (=1) or sensitivity (=1), were determined at 1-min intervals from 2-10 minutes of CPR using univariate logistic regression. Optimal predictor was selected by highest mean AUC. A stable specificity or sensitivity threshold was feasible if the mean threshold had a specificity or sensitivity >0.9 over all intervals, respectively. Results: Absolute change in StO 2 (ΔStO 2 ) had the highest mean (SD) AUC of 0.90 (0.07). Consistently >0.8, the AUC exceeded 0.9 after 7 minutes of CPR ( see Fig. ). The mean specificity threshold (ΔStO 2 = +5.1%) and sensitivity threshold (ΔStO 2 = +1.4%) achieved an overall specificity of 0.93 and sensitivity of 0.98, respectively. Conclusions: Non-invasive monitoring of absolute change in StO 2 was most predictive of ROSC and stable critical thresholds with high specificity or sensitivity were established in early CPR. Future work will independently validate this promising tool for CPR optimization.

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