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Polarization-sensitive hyperspectral imaging in vivo: a multimode dermoscope for skin analysis.

Vasefi F, MacKinnon N, Saager RB, Durkin AJ, Chave R, Lindsley EH, Farkas DL - Sci Rep (2014)

Bottom Line: This corrects for the melanin-hemoglobin misestimation common to other systems, without resorting to complex and computationally intensive tissue optical models.For this system's proof of concept, human skin measurements on melanocytic nevus, vitiligo, and venous occlusion conditions were performed in volunteers.The resulting molecular distribution maps matched physiological and anatomical expectations, confirming a technologic approach that can be applied to next generation dermoscopes and having biological plausibility that is likely to appeal to dermatologists.

View Article: PubMed Central - PubMed

Affiliation: Spectral Molecular Imaging Inc., 250 N. Robertson Blvd., Beverly Hills CA, USA 90211.

ABSTRACT
Attempts to understand the changes in the structure and physiology of human skin abnormalities by non-invasive optical imaging are aided by spectroscopic methods that quantify, at the molecular level, variations in tissue oxygenation and melanin distribution. However, current commercial and research systems to map hemoglobin and melanin do not correlate well with pathology for pigmented lesions or darker skin. We developed a multimode dermoscope that combines polarization and hyperspectral imaging with an efficient analytical model to map the distribution of specific skin bio-molecules. This corrects for the melanin-hemoglobin misestimation common to other systems, without resorting to complex and computationally intensive tissue optical models. For this system's proof of concept, human skin measurements on melanocytic nevus, vitiligo, and venous occlusion conditions were performed in volunteers. The resulting molecular distribution maps matched physiological and anatomical expectations, confirming a technologic approach that can be applied to next generation dermoscopes and having biological plausibility that is likely to appeal to dermatologists.

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Calculated relative skin chromophore distribution of melanocytic nevus and vitiligo showing reduction of melanin-hemoglobin misestimation.(a) Color cross-polarized image of nevus; (b) relative melanin (Mel); oxy-hemoglobin (oHb), deoxy-hemoglobin (Hb), total hemoglobin (tHb), and Oxygen Saturation Percentage (OSP) distribution for skin with nevus (c) before melanin correction, (d) after melanin correction; (e) Color cross-polarized image of vitiligo; (f) relative melanin (Mel), oxy-hemoglobin (oHb), deoxy-hemoglobin (Hb), total hemoglobin (tHb), and Oxygen Saturation Percentage (OSP) map of skin with vitiligo (g) before melanin correction, (h) after melanin correction (i) relative melanin, total hemoglobin concentration profile at A-A′ in melanocytic nevus (j) relative melanin, total hemoglobin concentration profile at B-B′ in vitiligo.
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f3: Calculated relative skin chromophore distribution of melanocytic nevus and vitiligo showing reduction of melanin-hemoglobin misestimation.(a) Color cross-polarized image of nevus; (b) relative melanin (Mel); oxy-hemoglobin (oHb), deoxy-hemoglobin (Hb), total hemoglobin (tHb), and Oxygen Saturation Percentage (OSP) distribution for skin with nevus (c) before melanin correction, (d) after melanin correction; (e) Color cross-polarized image of vitiligo; (f) relative melanin (Mel), oxy-hemoglobin (oHb), deoxy-hemoglobin (Hb), total hemoglobin (tHb), and Oxygen Saturation Percentage (OSP) map of skin with vitiligo (g) before melanin correction, (h) after melanin correction (i) relative melanin, total hemoglobin concentration profile at A-A′ in melanocytic nevus (j) relative melanin, total hemoglobin concentration profile at B-B′ in vitiligo.

Mentions: Figure 3 shows the derived chromophore maps of the skin with a melanocytic nevus (a–d) as well as skin with vitiligo (e–h). The skin melanin maps (see Figure 3b and Figure 3f) were calculated from the optical density spectra (OD⊥) in cross-polarization mode. For relative melanin estimation, we used a three-chromophore model including melanin, oxy-hemoglobin and deoxy-hemoglobin employing curve-fitting algorithms with the extinction coefficients of the chromophores as primary vectors. Figure 3c shows how high melanin concentration is conducive to misestimation of the hemoglobin concentrations. We applied our deep melanin estimation method described above to correct this hemoglobin misestimation. Figure 3d shows how this approach corrects the hemoglobin over-estimation in the nevus. The melanin corrected polarized attenuation spectrum (APOL-Mel_corrected) was employed for hemoglobin estimation using a two-chromophore (oHb and Hb) model and curve-fitting algorithms with the extinction coefficients of oHb and Hb as primary vectors in the 500 nm–577 nm spectral range.


Polarization-sensitive hyperspectral imaging in vivo: a multimode dermoscope for skin analysis.

Vasefi F, MacKinnon N, Saager RB, Durkin AJ, Chave R, Lindsley EH, Farkas DL - Sci Rep (2014)

Calculated relative skin chromophore distribution of melanocytic nevus and vitiligo showing reduction of melanin-hemoglobin misestimation.(a) Color cross-polarized image of nevus; (b) relative melanin (Mel); oxy-hemoglobin (oHb), deoxy-hemoglobin (Hb), total hemoglobin (tHb), and Oxygen Saturation Percentage (OSP) distribution for skin with nevus (c) before melanin correction, (d) after melanin correction; (e) Color cross-polarized image of vitiligo; (f) relative melanin (Mel), oxy-hemoglobin (oHb), deoxy-hemoglobin (Hb), total hemoglobin (tHb), and Oxygen Saturation Percentage (OSP) map of skin with vitiligo (g) before melanin correction, (h) after melanin correction (i) relative melanin, total hemoglobin concentration profile at A-A′ in melanocytic nevus (j) relative melanin, total hemoglobin concentration profile at B-B′ in vitiligo.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4017245&req=5

f3: Calculated relative skin chromophore distribution of melanocytic nevus and vitiligo showing reduction of melanin-hemoglobin misestimation.(a) Color cross-polarized image of nevus; (b) relative melanin (Mel); oxy-hemoglobin (oHb), deoxy-hemoglobin (Hb), total hemoglobin (tHb), and Oxygen Saturation Percentage (OSP) distribution for skin with nevus (c) before melanin correction, (d) after melanin correction; (e) Color cross-polarized image of vitiligo; (f) relative melanin (Mel), oxy-hemoglobin (oHb), deoxy-hemoglobin (Hb), total hemoglobin (tHb), and Oxygen Saturation Percentage (OSP) map of skin with vitiligo (g) before melanin correction, (h) after melanin correction (i) relative melanin, total hemoglobin concentration profile at A-A′ in melanocytic nevus (j) relative melanin, total hemoglobin concentration profile at B-B′ in vitiligo.
Mentions: Figure 3 shows the derived chromophore maps of the skin with a melanocytic nevus (a–d) as well as skin with vitiligo (e–h). The skin melanin maps (see Figure 3b and Figure 3f) were calculated from the optical density spectra (OD⊥) in cross-polarization mode. For relative melanin estimation, we used a three-chromophore model including melanin, oxy-hemoglobin and deoxy-hemoglobin employing curve-fitting algorithms with the extinction coefficients of the chromophores as primary vectors. Figure 3c shows how high melanin concentration is conducive to misestimation of the hemoglobin concentrations. We applied our deep melanin estimation method described above to correct this hemoglobin misestimation. Figure 3d shows how this approach corrects the hemoglobin over-estimation in the nevus. The melanin corrected polarized attenuation spectrum (APOL-Mel_corrected) was employed for hemoglobin estimation using a two-chromophore (oHb and Hb) model and curve-fitting algorithms with the extinction coefficients of oHb and Hb as primary vectors in the 500 nm–577 nm spectral range.

Bottom Line: This corrects for the melanin-hemoglobin misestimation common to other systems, without resorting to complex and computationally intensive tissue optical models.For this system's proof of concept, human skin measurements on melanocytic nevus, vitiligo, and venous occlusion conditions were performed in volunteers.The resulting molecular distribution maps matched physiological and anatomical expectations, confirming a technologic approach that can be applied to next generation dermoscopes and having biological plausibility that is likely to appeal to dermatologists.

View Article: PubMed Central - PubMed

Affiliation: Spectral Molecular Imaging Inc., 250 N. Robertson Blvd., Beverly Hills CA, USA 90211.

ABSTRACT
Attempts to understand the changes in the structure and physiology of human skin abnormalities by non-invasive optical imaging are aided by spectroscopic methods that quantify, at the molecular level, variations in tissue oxygenation and melanin distribution. However, current commercial and research systems to map hemoglobin and melanin do not correlate well with pathology for pigmented lesions or darker skin. We developed a multimode dermoscope that combines polarization and hyperspectral imaging with an efficient analytical model to map the distribution of specific skin bio-molecules. This corrects for the melanin-hemoglobin misestimation common to other systems, without resorting to complex and computationally intensive tissue optical models. For this system's proof of concept, human skin measurements on melanocytic nevus, vitiligo, and venous occlusion conditions were performed in volunteers. The resulting molecular distribution maps matched physiological and anatomical expectations, confirming a technologic approach that can be applied to next generation dermoscopes and having biological plausibility that is likely to appeal to dermatologists.

Show MeSH
Related in: MedlinePlus