Evaluation of the robustness of cerebral oximetry to variations in skin pigmentation using a tissue-simulating phantom

Afshari, Abbas; Saager, Rolf B.; Burgos, David; Vogt, William C.; Wang, Jianting; Mendoza, Gonzalo; Weininger, Sandy; Sung, Kung-Bin; Durkin, Anthony J.; Pfefer, T. Joshua

doi:10.1364/boe.454020

Cited by 24 publications

(25 citation statements)

References 53 publications

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“…Although their magnitudes are on the higher end, they still fall within the range of established values. Further comparisons can be seen in Figure S2, where the absorption coefficient of this OTP is compared with other epidermal OTPs from the literature. − The values of this work are comparable to that of other publications, with a moderate bias toward OTPs with higher degrees of pigmentation. Thus, although the absorption coefficient values of the epidermis OTP are reasonable, they may be better suited for modeling the absorption coefficients of darker pigmented skin tones rather than those of lighter skin.…”

Section: Resultssupporting

confidence: 74%

Optical Epidermal Mimicry from Ultraviolet to Infrared Wavelengths

Caratenuto

Wan

et al. 2022

ACS Appl. Bio Mater.

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Optical tissue phantoms present substantial value for medical imaging and therapeutic applications. We have developed an epidermal tissue phantom to mimic the optical properties of human skin from the ultraviolet to the infrared region, exceeding the breadth of existing studies. An epoxy matrix is combined with melanin-mimicking polydopamine via a cost-effective fabrication strategy. Reflectance and transmittance measurements enable calculation of the wavelength-dependent complex refractive index and absorption coefficient. Results are compared with literature data to establish agreement with a real human epidermis. By analyzing emissive power at a typical skin temperature, the epidermal tissue phantom is shown to accurately mimic the radiative properties of human skin. This simple, multifunctional material represents a promising substitute for human tissue for a variety of medical and bioengineering applications.

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Section: Resultssupporting

confidence: 74%

Optical Epidermal Mimicry from Ultraviolet to Infrared Wavelengths

Caratenuto

Wan

et al. 2022

ACS Appl. Bio Mater.

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“…1, 3, and 5 skin phantoms decreased 1, 3, and 6 mJ energy at 680 nm which is relevant to the absorption peak of deoxyhemoglobin (660 nm). [ 23 ] Moreover, the 680‐nm laser attenuated 1.3‐ and 1.98‐fold more energy than 800 and 1064 nm lasers, respectively, because of higher light absorption and scattering of synthetic melanin. To further evaluate this, µ a and µ s ′ of skin‐tone phantoms (Fitz.…”

Section: Resultsmentioning

confidence: 99%

“…It protects against injury, shields radiation, and offers cohort studies are ideal to define and rectify such bias, tissuemimicking phantoms that recreate the optical properties of human skin as a function of skin phototypes could offer dramatic time-and cost-savings. [23,24] These phantoms would be attractive to regulatory agencies, device development firms, and patients.…”

Section: Introductionmentioning

confidence: 99%

“…Here, we engineered 3D-bioprinted phantoms with skin phototypes containing synthetic melanin with controllable particle sizes and clustering to mimic the epidermis of different skin phototypes ranging from Fitzpatrick (Fitz) scale 1 to 6. [23,25] The PA signal of human skin changes as a function of melanin absorption: [26,27] the light absorbed by melanin is converted to spatially confined heat that generates acoustic waves. [28][29][30] This implies that PA can indirectly measure melanosome content and distribution in human skin.…”

Section: Introductionmentioning

confidence: 99%

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3D‐Bioprinted Phantom with Human Skin Phototypes for Biomedical Optics

et al. 2022

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Skin consists of a lamellar structure with diverse cell types (e.g., immune cells, melanocytes, and basal cells) that periodically detach from the basement membrane, move to the surface, and die for self-renewal. [3] Melanocytes are a critical cell type that generate melanin to absorb UV light (290-400 nm), which is a major risk for skin diseases (e.g., melanoma) due to DNA damage. [4][5][6][7] Here, melanin-containing organelles called melanosomes are transferred to the surrounding keratinocytes. This increase in melanosome concentration leads to darker skin phototypes, and darker phototypes can be a function of racial background or previous sun exposure, that is, tanning. [8] Indeed, skin pigmentation depends on variations in the size, number, clustering phase, and the proportions between melanin species (e.g., eumelanin and pheomelanin). [9] Skin pigmentation has been quantified using melanosome volume fraction (M f ) parameter: 1.3-6.3% for lightly pigmented adults, 11-16% for moderately pigmented adults, and 18-43% for darkly pigmented adults. [10] Variations in skin phototypes can complicate biomedical optics. Melanin absorption increases linearly from 800 to 600 nm and exponentially from 600 to 300 nm. [11,12] Darker skin phototypes can absorb and scatter more photons: as a result, incident light is attenuated before it reaches the target of interest, and signal transmission can be impeded back to the sensor. Therefore, variations in skin phototypes have negatively affected many forms of medical optic technology including pulse oximetry, [13,14] cerebral tissue oximeters, [15] optical coherence tomography, [16] wearable electronics, [17][18][19] photoacoustic (PA) imaging, [20] fluorescence imaging, [21] and photothermal therapy. [22] One recent study compared 48 097 pairs of oxygen saturation levels measured by pulse oximetry and arterial blood gas test obtained from 8675 white patients and 1326 black patients. [13] The results found that pulse oximetry had trouble in diagnosing hypoxemia in 11% Black patients and 3% white patients due to light absorption by melanin. [13,14] Furthermore, wearable electronics (e.g., smartwatches) have reported inaccuracies in heart rate readings occurring more often in users with dark skin than light skin. [17,18] Clearly, the impact of differences in skin phototypes underscore the ongoing need to understand and correct racial bias in optical technologies. While larger 3D-bioprinted skin-mimicking phantoms with skin colors ranging across the Fitzpatrick scale are reported. These tools can help understand the impact of skin phototypes on biomedical optics. Synthetic melanin nanoparticles of different sizes (70-500 nm) and clusters are fabricated to mimic the optical behavior of melanosome. The absorption coefficient and reduced scattering coefficient of the phantoms are comparable to real human skin. Further the melanin content and distribution in the phantoms versus real human skins are validated via photoacoustic (PA) imaging. The PA signal of the phantom can be improved ...

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“…In modern cerebral oximeters, wavelengths have been added to enable a more precise determination of hemoglobin and to be less sensitive to skin pigmentation. Very recently, the robustness of two commercial NIRS-based cerebral oximeters (using four or five wavelengths) to variations in skin pigmentation was evaluated using a tissue-simulating phantom; unexpectedly increasing melanin content decreased saturation values displayed by both devices [ 5 ]. The effect of skin pigmentation was particularly inflicted when using a neonatal sensor.…”

mentioning

confidence: 99%