Significance: Fiber-optic extended-wavelength diffuse reflectance spectroscopy (EWDRS) using both visible/near-infrared and shortwave-infrared detectors enables improved detection of spectral absorbances arising from lipids, water, and collagen and has demonstrated promise in a variety of applications, including detection of nerves and neurovascular bundles (NVB). Development of future applications of EWDRS for nerve detection could benefit from the use of model-based analyses including Monte Carlo (MC) simulations and evaluation of agreement between model systems and empirical measurements.Aim: The aim of this work is to characterize agreement between EWDRS measurements and simulations and inform future applications of model-based studies of nerve-detecting applications.Approach: A model-based platform consisting of an ex vivo microsurgical nerve dissection model, unique two-layer optical phantoms, and MC model simulations of fiber-optic EWDRS spectroscopic measurements were used to characterize EWDRS and compare agreement across models. In addition, MC simulations of an EWDRS measurement scenario are performed to provide a representative example of future analyses.Results: EWDRS studies performed in the common chicken thigh femoral nerve microsurgical dissection model indicate similar spectral features for classification of NVB versus adjacent tissues as reported in porcine models and human subjects. A comparison of measurements from unique EWDRS issue mimicking optical phantoms and MC simulations indicates high agreement between the two in homogeneous and two-layer optical phantoms, as well as in dissected tissues. Finally, MC simulations of measurement over a simulated NVB indicate the potential of future applications for measurement of nerve plexus.Conclusions: Characterization of agreement between fiber-optic EWDRS measurements and MC simulations demonstrates strong agreement across a variety of tissues and optical phantoms, offering promise for further use to guide the continued development of EWDRS for translational applications.
KEYWORDS: Tissues, Monte Carlo methods, Animal model studies, Statistical modeling, Optical properties, Optical phantoms, Diffuse reflectance spectroscopy, Near infrared
Extended-wavelength diffuse reflectance spectroscopy (EWDRS) combines two spectrometers extending the wavelength range up to 1500 nm, which provides more information than visible or near-infrared DRS alone and indicates the improved ability to differentiate biological tissues. Identification of Neurovascular bundles (NVB) is a main challenging during surgery, while current EWDRS studies have been prove the ability in open surgeries. However, theoretical simulations for complex multilayer structure in EWDRS range have yet to be reported. Monte Carlo (MC) model has been developed to accurately simulate the random propagations in complex and multilayered structures in various optical applications. We report the design and development of an EWDRS system with a fiber optic EWDRS probe. In addition, 2-layer tissue simulating phantoms with different top-layer thickness are developed and MC simulations of EWDRS spectra based on the optical properties of phantoms are compared against empirical measurements, demonstrating the accuracy of MC model in simulating multilayers structures and a superficial bias in probe sampling volume. Finally, measurements taken during dissection of the NVB in an ex vivo chicken thigh animal model are reported and confirm the ability of EWDRS to identify peripheral NVB from adjacent tissues. The results showed the developed phantoms had the ability to mimic blood content and lipid absorption features in visible and near-infrared region and simulated spectra had same tendency as measured spectra. Additionally, the classification results from the animal model displayed the overall accuracy was over 92%, which indicated the feasibility of identification of NVB from adjacent tissues.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.