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Fairfield, NJ, United States

D'Alessandro B.,Canfield Scientific | Dhawan A.P.,New Jersey Institute of Technology
IEEE Transactions on Biomedical Engineering | Year: 2012

Detecting the early stages of melanoma can be greatly assisted by an accurate estimate of subsurface blood volume and blood oxygen saturation, indicative of angiogenesis. Visualization of this blood volume present beneath a skin lesion can be achieved through the transillumination of the skin. As the absorption of major chromophores in the skin is wavelength dependent, multispectral imaging can provide the needed information to separate out relative amounts of each chromophore. However, a critical challenge to this strategy is relating the pixel intensities observed in a given image to the wavelength-dependent total absorption existing at each spatial location. Consequently, in this paper, we develop an extension to Beers law, estimated through a novel voxel-based, parallel processing Monte Carlo simulation of light propagation in skin which takes into account the specific geometry of our transillumination imaging apparatus. We then use this relation in a linear mixing model, solved using a multispectral image set, for chromophore separation and oxygen saturation estimation of an absorbing object located at a given depth within the medium. Validation is performed through the Monte Carlo simulation, as well as by imaging on a skin phantom. Results show that subsurface oxygen saturation can be reasonably estimated with good implications for the reconstruction of 3-D skin lesion volumes using transillumination toward early detection of malignancy. © 2012 IEEE. Source


Dobos G.,Charite - Medical University of Berlin | Trojahn C.,Charite - Medical University of Berlin | Lichterfeld A.,Charite - Medical University of Berlin | DAlessandro B.,Canfield Scientific | And 4 more authors.
International Journal of Cosmetic Science | Year: 2015

Objective The skin melanin system is affected by ageing, resulting in dyspigmentation with associated clinical and psychosocial consequences. In dark skinned phenotypes, broad evidence is available, whereas little is known about pigmentary changes in fair-skinned Caucasians. The objective of this study was to investigate age-related changes in facial pigmentation and dyspigmentation in subjects of skin phototypes II-III and to develop and test parameters for quantifying dyspigmentation. Methods Twenty-four skin healthy female subjects were recruited in three distinct age groups (30-40, 50-60, 70-80 years). Skin colour was measured by Mexameter and Chromameter. Skin dyspigmentation was measured by clinical evaluation and newly developed image-processing parameters on the cheeks and the forehead. The reliability of the clinical evaluation was investigated by intraclass correlation coefficients between three raters, and the validity of the dyspigmentation parameters was analysed by bivariate correlations with related measures. Results Skin lightness decreased with increasing age. Clinical dyspigmentation scores showed positive associations with chronological age ranging between 0.452 and 0.606. RBX®-Brown transformation-based hyperpigmentation and hypopigmentation indices increased with age, whereas the overall pigmentation intensity decreased with age at the cheeks. The image analysis-based parameters showed strong associations with the clinical scores and related measurements. Conclusion We demonstrated age-related changes in the facial colour and dyspigmentation of fair-skinned Caucasian females. An increase in dyspigmentation was found by clinical scoring and the RBX®-Brown transformation-based pigmentation indices. The validity of hyper- and hypopigmentation indices and overall pigmentation intensity was supported. The RBX® transformation-based pigmentation indices might be applied in future studies to complement or substitute clinical evaluation. © 2015 Society of Cosmetic Scientists. Source

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