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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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Related in: MedlinePlus

(a) Skin mole boundaries determined from the grayscale image at 500 nm (white) compared to the image at 700 nm (green); (b) resolution target boundaries determined from the grayscale image at 500 nm (white) compared to the image at 700 nm (green); (c) skin mole boundaries determined from the successive scans (typical, not best result); (d) image registration between parallel and cross polarization images.
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f6: (a) Skin mole boundaries determined from the grayscale image at 500 nm (white) compared to the image at 700 nm (green); (b) resolution target boundaries determined from the grayscale image at 500 nm (white) compared to the image at 700 nm (green); (c) skin mole boundaries determined from the successive scans (typical, not best result); (d) image registration between parallel and cross polarization images.

Mentions: In Figure 6a, we show the skin mole boundary determined from the grayscale image at 500 nm compared to the image at 700 nm. The images show a boundary difference (likely due to wavelength dependent differences in melanin absorption and scattering), however the images are closely registered showing virtually no motion artifact during hyperspectral scans. The optical resolution of the system is 7 pixels (~300 μm) in the cross polarization mode, as shown by imaging a USAF 1951 resolution target. The image registration shift between the boundaries of USAF 1951 target at 500 nm and 700 nm was 2 pixels as shown in as Figure 6b. We think this is due to chromatic aberration in the optical system from the beam splitter. If we assume the spot size is roughly equivalent to the optical resolution in cross polarized mode, the registration shift is less than the spot size resolution and image re-registration due to motion artifact during hyperspectral imaging and chromatic aberration is likely unnecessary. We also analyzed motional artifact effect by capturing three successive measurement sequences. The measurement sequence requires 4 seconds and we waited 10 seconds between the scans. As shown in as Figure 6c, skin mole boundaries in images from three successive scans at the same wavelength (500 nm) and polarization state show at most 5 pixels translation and the image translation is slightly less than the optical resolution. Figure 6d shows the image registration between two polarization images by overlapping the boundary image of USAF 1951 target from Z∥ at 500 nm on the grayscale reflectance image of Z⊥. The image misregistration between Z∥ and Z⊥ is less than the limiting optical resolution of the system.


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)

(a) Skin mole boundaries determined from the grayscale image at 500 nm (white) compared to the image at 700 nm (green); (b) resolution target boundaries determined from the grayscale image at 500 nm (white) compared to the image at 700 nm (green); (c) skin mole boundaries determined from the successive scans (typical, not best result); (d) image registration between parallel and cross polarization images.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f6: (a) Skin mole boundaries determined from the grayscale image at 500 nm (white) compared to the image at 700 nm (green); (b) resolution target boundaries determined from the grayscale image at 500 nm (white) compared to the image at 700 nm (green); (c) skin mole boundaries determined from the successive scans (typical, not best result); (d) image registration between parallel and cross polarization images.
Mentions: In Figure 6a, we show the skin mole boundary determined from the grayscale image at 500 nm compared to the image at 700 nm. The images show a boundary difference (likely due to wavelength dependent differences in melanin absorption and scattering), however the images are closely registered showing virtually no motion artifact during hyperspectral scans. The optical resolution of the system is 7 pixels (~300 μm) in the cross polarization mode, as shown by imaging a USAF 1951 resolution target. The image registration shift between the boundaries of USAF 1951 target at 500 nm and 700 nm was 2 pixels as shown in as Figure 6b. We think this is due to chromatic aberration in the optical system from the beam splitter. If we assume the spot size is roughly equivalent to the optical resolution in cross polarized mode, the registration shift is less than the spot size resolution and image re-registration due to motion artifact during hyperspectral imaging and chromatic aberration is likely unnecessary. We also analyzed motional artifact effect by capturing three successive measurement sequences. The measurement sequence requires 4 seconds and we waited 10 seconds between the scans. As shown in as Figure 6c, skin mole boundaries in images from three successive scans at the same wavelength (500 nm) and polarization state show at most 5 pixels translation and the image translation is slightly less than the optical resolution. Figure 6d shows the image registration between two polarization images by overlapping the boundary image of USAF 1951 target from Z∥ at 500 nm on the grayscale reflectance image of Z⊥. The image misregistration between Z∥ and Z⊥ is less than the limiting optical resolution of the system.

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