Layer thickness prediction and tissue classification in two-layered tissue structures using diffuse reflectance spectroscopy

Geldof, Freija; Dashtbozorg, Behdad; Hendriks, Benno H. W.; Sterenborg, Henricus J. C. M.; Ruers, Theo J.M.

doi:10.1038/s41598-022-05751-5

Cited by 14 publications

(10 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Neural networks can also be used to quickly ( 50 ms) estimate tissue optical properties in inverse problems 49 . However, they require long training times and are roughly 1000× slower than the presented analytical model for forward calculations 49 , 50 . Several solutions for photon diffusion in layered media have been reported, but present technical difficulties for numerical computation.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Efficient computation of the steady-state and time-domain solutions of the photon diffusion equation in layered turbid media

Helton

Zerafa

Vishwanath

et al. 2022

Sci Rep

View full text Add to dashboard Cite

Accurate and efficient forward models of photon migration in heterogeneous geometries are important for many applications of light in medicine because many biological tissues exhibit a layered structure of independent optical properties and thickness. However, closed form analytical solutions are not readily available for layered tissue-models, and often are modeled using computationally expensive numerical techniques or theoretical approximations that limit accuracy and real-time analysis. Here, we develop an open-source accurate, efficient, and stable numerical routine to solve the diffusion equation in the steady-state and time-domain for a layered cylinder tissue model with an arbitrary number of layers and specified thickness and optical coefficients. We show that the steady-state ($$< 0.1$$ < 0.1 ms) and time-domain ($$< 0.5$$ < 0.5 ms) fluence (for an 8-layer medium) can be calculated with absolute numerical errors approaching machine precision. The numerical implementation increased computation speed by 3 to 4 orders of magnitude compared to previously reported theoretical solutions in layered media. We verify our solutions asymptotically to homogeneous tissue geometries using closed form analytical solutions to assess convergence and numerical accuracy. Approximate solutions to compute the reflected intensity are presented which can decrease the computation time by an additional 2–3 orders of magnitude. We also compare our solutions for 2, 3, and 5 layered media to gold-standard Monte Carlo simulations in layered tissue models of high interest in biomedical optics (e.g. skin/fat/muscle and brain). The presented routine could enable more robust real-time data analysis tools in heterogeneous tissues that are important in many clinical applications such as functional brain imaging and diffuse optical spectroscopy.

show abstract

Section: Discussionmentioning

confidence: 99%

“…Skin, fat, muscle model 32 Brain model 43 www.nature.com/scientificreports/ calculations 49,50 . Several solutions for photon diffusion in layered media have been reported, but present technical difficulties for numerical computation.…”

Section: Discussionmentioning

confidence: 99%

Efficient computation of the steady-state and time-domain solutions of the photon diffusion equation in layered turbid media

Helton

Zerafa

Vishwanath

et al. 2022

Sci Rep

View full text Add to dashboard Cite

show abstract

“…The fact that the interrogation depth varies with fiber distance or spatial frequency also offers the opportunity to extract depth information on tissue optical properties. For example, fiber-optic probes with multiple fibers distances and SFDI with multiple frequencies have been used to extract optical properties of different tissue layers, as well as the thickness of the layers (Sharma et al, 2014;Tabassum et al, 2018;Geldof et al, 2022;Sung et al, 2022). Also, in the very first paper where SFDI A pitfall in the development of diagnostic algorithms is not realizing that results from one fiber distance or spatial frequency cannot simply be translated to another fiber distance or spatial frequency.…”

Section: Interrogation Depthmentioning

confidence: 99%

Opportunities and pitfalls in (sub)diffuse reflectance spectroscopy

et al. 2022

Self Cite

View full text Add to dashboard Cite

For a long time, steady-state reflectance spectroscopy measurements have been performed so that diffusion theory could be used to extract tissue optical properties from the reflectance. The development of subdiffuse techniques, such as Single Fiber Reflectance Spectroscopy and subdiffuse SFDI, provides new opportunities for clinical applications since they have the key advantage that they are much more sensitive to the details of the tissue scattering phase function in comparison to diffuse techniques. Since the scattering phase function is related to the subcellular structure of tissue, subdiffuse measurements have the potential to provide a powerful contrast between healthy and diseased tissue. In the subdiffuse regime, the interrogated tissue volumes are much smaller than in the diffuse regime. Whether a measurement falls within the diffuse or subdiffuse regime depends on tissue optical properties and the distance between the source and detector fiber for fiber-optic techniques or the projected spatial frequency for hyperspectral imaging and SFDI. Thus, the distance between source and detector fibers or the projected spatial frequency has important implications for clinical applications of reflectance spectroscopy and should be carefully selected, since it influences which tissue optical properties the technique is sensitive to and the size of the tissue volume that is interrogated. In this paper, we will review the opportunities and pitfalls in steady-state reflectance spectroscopy in the subdiffuse and the diffuse regime. The discussed opportunities can guide the choice of either the diffuse or subdiffuse regime for a clinical application, and the discussed pitfalls can ensure these are avoided to enable the development of robust diagnostic algorithms. We will first discuss the relevant basics of light-tissue interaction. Next, we will review all the tissue scattering phase functions that have been measured and investigate which scattering phase function models are representative of tissue. Subsequently, we will discuss the sensitivity of diffuse and subdiffuse techniques to tissue optical properties and we will explore the difference in the interrogation depth probed by diffuse and subdiffuse techniques.

show abstract

“… 10 , 11 Near infrared (NIR) spectroscopy and imaging allow water content assessment in deeper layers (dermis and hypodermis). 3 , 12 , 13 For instance, in heart failure patients, peripheral edema was analyzed with short-wave NIR imaging. 2 Cutaneous edema induced by histamine application was studied with diffuse reflectance spectroscopy (DRS), 9 , 14 Raman fiber probe, 9 and multispectral NIR imaging.…”

Section: Introductionmentioning

confidence: 99%

“…However, the problem of determining water in vivo using this technique has not been considered previously. The SR DRS has also been applied for determining the thicknesses of tissue layers in ex vivo samples and optical phantoms 12 , 25 , 26 thus making it a promising technique for sensing the properties of individual skin layers in vivo . This issue was also addressed in the present study.…”

Section: Introductionmentioning

confidence: 99%

Monitoring the skin structure during edema in vivo with spatially resolved diffuse reflectance spectroscopy

Davydov,

Budylin,

Baev

et al. 2023

J. Biomed. Opt.

View full text Add to dashboard Cite

. Significance Edema occurs in the course of various skin diseases. It manifests itself in changes in water concentrations in skin layers: dermis and hypodermis and their thicknesses. In medicine and cosmetology, objective tools are required to assess the skin’s physiological parameters. The dynamics of edema and the skin of healthy volunteers were studied using spatially resolved diffuse reflectance spectroscopy (DRS) in conjunction with ultrasound (US). Aim In this work, we have developed a method based on DRS with a spatial resolution (SR DRS), allowing us to simultaneously assess water content in the dermis, dermal thickness, and hypodermal thickness. Approach An experimental investigation of histamine included edema using SR DRS under the control of US was conducted. An approach for skin parameter determination was studied and confirmed using Monte-Carlo simulation of diffuse reflectance spectra for a three-layered system with the varying dermis and hypodermis parameters. Results It was shown that an interfiber distance of 1 mm yields a minimal relative error of water content determination in the dermis equal to 9.3%. The lowest error of hypodermal thickness estimation was achieved with the interfiber distance of 10 mm. Dermal thickness for a group of volunteers (7 participants, 21 measurement sites) was determined using SR DRS technique with an 8.3% error using machine learning approaches, taking measurements at multiple interfiber distances into account. Hypodermis thickness was determined with root mean squared error of 0.56 mm for the same group. Conclusions This study demonstrates that measurement of the skin diffuse reflectance response at multiple distances makes it possible to determine the main parameters of the skin and will serve as the basis for the development and verification of an approach that works in a wide range of skin structure parameters.

show abstract

Layer thickness prediction and tissue classification in two-layered tissue structures using diffuse reflectance spectroscopy

Cited by 14 publications

References 54 publications

Efficient computation of the steady-state and time-domain solutions of the photon diffusion equation in layered turbid media

Efficient computation of the steady-state and time-domain solutions of the photon diffusion equation in layered turbid media

Opportunities and pitfalls in (sub)diffuse reflectance spectroscopy

Monitoring the skin structure during edema in vivo with spatially resolved diffuse reflectance spectroscopy

Contact Info

Product

Resources

About