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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) SkinSpect research prototype system diagram and the (b) SkinSpect console; (c) SkinSpect data output includes reflection images over the range from 467 nm to 857 nm, in parallel and cross polarization modes.
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f5: (a) SkinSpect research prototype system diagram and the (b) SkinSpect console; (c) SkinSpect data output includes reflection images over the range from 467 nm to 857 nm, in parallel and cross polarization modes.

Mentions: As shown in Figure 5a, the system consists of a console and a handpiece probe. A computer (UNIX operating system) controls the specimen illumination and data acquisition, image processing, archiving and data transmission. Additionally, a touch-screen computer (Windows OS) is employed to create a user-friendly, touch-responsive interface and manage patient record data and visual interfaces (Figure 5b). The spectrally programmable OneLight Spectra illumination system has a Xenon arc light source and microelectromechanically-based wavelength selection ability over the range from 468 nm to 857 nm. The handpiece contains two cameras; a central chassis; a beam splitter; and fiber guides that direct the light from the console illumination source to a fixture that positions this assembly at the correct depth to illuminate the tissue surface. Our device provides diffuse illumination to skin in a geometry that limits the amount of specular reflection to the detector. A ring-shaped linear polarizer is placed in front of the fiber optics to allow only linearly polarized light to illuminate the tissue surface. The two cameras each have a polarization filter installed and oriented orthogonally to one another. This configuration captures images of the skin that maintain the linear polarization present in reflectance from both surface and deeper layers of tissue), and cross polarization images. A synchronized image acquisition by the two spatially registered cameras generates two images of an 11 mm × 16 mm area of skin in both parallel and cross polarizations. Image stacks are acquired by hyperspectral imaging of the target area enabled by the sequential illumination with 33 wavelength bands from visible (468 nm) to near infrared range (857 nm), with a wavelength step interval of ~13 nm. Moreover, digital color images can be generated by programming the light source for broadband illumination to mimic typical Bayer filters that are used in conventional color cameras. These color images are provided for display or for comparison with standard dermoscopes. Additional system details are described in22. Figure 5c shows a sample of the SkinSpect representation after sequential image capture. The minimum spatially resolvable line-width detected by the P and X cameras was approximately 110 μm, measured by imaging a USAF 1951 resolution test target.


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) SkinSpect research prototype system diagram and the (b) SkinSpect console; (c) SkinSpect data output includes reflection images over the range from 467 nm to 857 nm, in parallel and cross polarization modes.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f5: (a) SkinSpect research prototype system diagram and the (b) SkinSpect console; (c) SkinSpect data output includes reflection images over the range from 467 nm to 857 nm, in parallel and cross polarization modes.
Mentions: As shown in Figure 5a, the system consists of a console and a handpiece probe. A computer (UNIX operating system) controls the specimen illumination and data acquisition, image processing, archiving and data transmission. Additionally, a touch-screen computer (Windows OS) is employed to create a user-friendly, touch-responsive interface and manage patient record data and visual interfaces (Figure 5b). The spectrally programmable OneLight Spectra illumination system has a Xenon arc light source and microelectromechanically-based wavelength selection ability over the range from 468 nm to 857 nm. The handpiece contains two cameras; a central chassis; a beam splitter; and fiber guides that direct the light from the console illumination source to a fixture that positions this assembly at the correct depth to illuminate the tissue surface. Our device provides diffuse illumination to skin in a geometry that limits the amount of specular reflection to the detector. A ring-shaped linear polarizer is placed in front of the fiber optics to allow only linearly polarized light to illuminate the tissue surface. The two cameras each have a polarization filter installed and oriented orthogonally to one another. This configuration captures images of the skin that maintain the linear polarization present in reflectance from both surface and deeper layers of tissue), and cross polarization images. A synchronized image acquisition by the two spatially registered cameras generates two images of an 11 mm × 16 mm area of skin in both parallel and cross polarizations. Image stacks are acquired by hyperspectral imaging of the target area enabled by the sequential illumination with 33 wavelength bands from visible (468 nm) to near infrared range (857 nm), with a wavelength step interval of ~13 nm. Moreover, digital color images can be generated by programming the light source for broadband illumination to mimic typical Bayer filters that are used in conventional color cameras. These color images are provided for display or for comparison with standard dermoscopes. Additional system details are described in22. Figure 5c shows a sample of the SkinSpect representation after sequential image capture. The minimum spatially resolvable line-width detected by the P and X cameras was approximately 110 μm, measured by imaging a USAF 1951 resolution test target.

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