MULTI-SPECTRAL TISSUE IMAGING

• US 20140364745A1
• Filed: 08/21/2014
• Published: 12/11/2014
• Est. Priority Date: 11/26/2007
• Status: Active Grant

• Current Assignee: Canfield Scientific Incorporated
• Original Assignee: Canfield Scientific Incorporated
• Inventors: Patwardhan, Sachin V.
• Granted Patent: US 10,130,260 B2
• Time in Patent Office: Days
• US Class Current: 600/476
• CPC Class Codes: A61B 2576/00 Medical imaging apparatus involving image processing or analysis A61B1/00009, A61B6/52 and A61B8/52 take precedence; image processing per se G06T; details of algorithms for analysing medical images G06T7/0012
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/0064 Body surface scanning
• CPC Class Codes: A61B 5/0071 by measuring fluorescence emission
• CPC Class Codes: A61B 5/0075 by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy A61B5/0071 takes precedence
• CPC Class Codes: A61B 5/442 Evaluating skin mechanical properties, e.g. elasticity, hardness, texture, wrinkle assessment
• CPC Class Codes: A61B 5/443 Evaluating skin constituents, e.g. elastin, melanin, water
• CPC Class Codes: A61B 5/444 Evaluating skin marks, e.g. mole, nevi, tumour, scar
• CPC Class Codes: A61B 5/445 Evaluating skin irritation or skin trauma, e.g. rash, eczema, wound, bed sore
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence

Abstract

Apparatus and methods are disclosed for multi-spectral imaging of tissue to obtain information about the distribution of fluorophores and chromophores in the tissue. Using specific spectral bands for illumination and specific spectral bands for detection, the signal-to-noise ratio and information related to the distribution of specific fluorophores is enhanced as compared to UV photography, which uses a single RGB image. Furthermore, the chromophore distribution information derived from the multi-spectral absorption images can be used to correct the fluorescence measurements. The combined fluorescence, absorption, and broadband reflectance data can be analyzed for disease diagnosis and skin feature detection.

Claims

1-54. -54. (canceled)

55. A method of imaging human skin in vivo comprising:

capturing a fluorescence reflectance image of the human skin;

capturing a cross-polarized broadband white light reflectance image of the human skin;

processing the cross-polarized broadband white light reflectance image to obtain a chromophore distribution image; and

generating a normalized fluorescence image by normalizing the fluorescence reflectance image with respect to the chromophore distribution image.

56. The method of claim 55, wherein processing the cross-polarized broadband white light reflectance image includes at least one of a color space transformation, an Independent Component Analysis (ICA) and a Principle Component Analysis (PCA).

57. The method of claim 55 comprising:

filtering light reflected from the tissue to eliminate at least one of an ultraviolet and an infrared light.

58. The method of claim 55, wherein the chromophore distribution image includes a distribution of at least one chromophore selected from the group consisting of hemoglobin, melanin and bilirubin.

59. The method of claim 55 comprising:

storing at least one of the fluorescence reflectance image, the normalized fluorescence image, the cross-polarized broadband white light reflectance image and the chromophore distribution image; and

displaying at least one of the fluorescence reflectance image, the cross-polarized broadband white light reflectance image and the chromophore distribution image.

60. The method of claim 55 comprising identifying a skin pathological condition selected from the group consisting of rosacea, hyper-pigmentation, ultraviolet light damage, melanin spots, nevi, sun tan, erythema, inflammation, irritation, and skin lesion.

61. The method of claim 55 comprising:

using at least one of the fluorescence reflectance image, the normalized fluorescence image, the chromophore distribution image, and the cross-polarized broadband white light reflectance image for;

identifying scars and spots,

classifying inflammatory from non-inflammatory lesions,

evaluating erythema by analyzing hemoglobin information,

detecting wrinkles,

predicting future wrinkle development,

evaluating skin hydration levels using water absorption information,

evaluating at least one of a normal, dysplastic, and malignant skin lesion,

classifying at least one of a normal, dysplastic, and malignant lesion,

evaluating at least one of a skin pathology including rosacea, hyper-pigmentation, skin burn, irritation, and inflammation,

classifying an acne lesion as being of a type including at least one of an open comedone, closed comedone, papule, pustule, nodule, cyst, burnt-out lesion, and excoriated lesion,

predicting future acne lesion formation sites,

evaluating at least one of a treatment product and a treatment procedure;

or

recommending at least one of a treatment product and a treatment procedure.

62. The method of claim 55 comprising processing the normalized fluorescence image so as to characterize a condition of the tissue.

63. The method of claim 62 comprising at least one of:

communicating at least one of the normalized fluorescence image and the processed normalized fluorescence image;

storing at least one of the normalized fluorescence image and the processed normalized fluorescence image; and

displaying at least one of the normalized fluorescence image and the processed normalized fluorescence image.

64. The method of claim 55, wherein the fluorescence reflectance image is obtained by:

illuminating the human skin with a narrow spectral band illumination which excites a plurality of endogenous fluorophores including an endogenous target fluorophore of the human skin to each generate an emission signal;

filtering the emission signals so as to pass the emission signal of the target fluorophore and of at least one other of the plurality of fluorophores while suppressing emissions from at least one other source;

capturing a reflectance image of the human skin by detecting the filtered emission signals;

capturing an excitation image so as to characterize a light distribution over a surface of the human skin by detecting light reflected from the human skin; and

normalizing the captured reflectance image using the excitation image,

wherein the narrow spectral band illumination and the filtering are selected so that the filtered emission signal of the target fluorophore can be individually detected among the filtered emission signals.

65. The method of claim 64, wherein a wavelength range of the narrow spectral band illumination is selected so as to optimally excite the target fluorophore.

66. The method of claim 64, wherein the at least one other source includes at least one of a further fluorophore, an ambient light source, and an excitation light source.

67. The method of claim 64, wherein:

the narrow spectral band illumination is centered around 405 nm (±

15 nm), and

the filtering is performed with a 10 to 50 nm (FWHM) narrow band-pass filter centered around 460 nm (±

20 nm), for detecting a collagen fluorescence signal.

68. The method of claim 64, wherein:

the narrow spectral band illumination is centered around 405 nm (±

15 nm), and

the filtering is performed with a 10 to 50 nm (FWHM) narrow band-pass filter centered around 560 nm (±

20 nm), for detecting a horns fluorescence signal.

69. The method of claim 64, wherein:

the narrow spectral band illumination is centered around 405 nm (±

15 nm), and

the filtering is performed with a long-pass filter with a cut-off wavelength of approximately 620 nm for detecting a porphyrin fluorescence signal.

70. The method of claim 64, wherein:

the narrow spectral band illumination is centered around 350 nm (±

15 nm),

the target fluorophore includes elastin, and

the filtering is performed with a 10 to 50 nm (FWHM) narrow band-pass filter centered around 410 nm (±

20 nm).