Hyperspectral imaging in the spatial frequency domain with a supercontinuum source.

Mohammad Torabzadeh,Gordon T Kennedy,Anthony J Durkin,Randy A Bartels,Bruce J Tromberg,Patrick A Stockton,Rolf B Saager

doi:10.1117/1.jbo.24.7.071614

Abstract

.We introduce a method for quantitative hyperspectral optical imaging in the spatial frequency domain (hs-SFDI) to image tissue absorption () and reduced scattering () parameters over a broad spectral range. The hs-SFDI utilizes principles of spatial scanning of the spectrally dispersed output of a supercontinuum laser that is sinusoidally projected onto the tissue using a digital micromirror device. A scientific complementary metal–oxide–semiconductor camera is used for capturing images that are demodulated and analyzed using SFDI computational models. The hs-SFDI performance is validated using tissue-simulating phantoms over a range of and values. Quantitative hs-SFDI images are obtained from an ex-vivo beef sample to spatially resolve concentrations of oxy-, deoxy-, and met-hemoglobin, as well as water and fat fractions. Our results demonstrate that the hs-SFDI can quantitatively image tissue optical properties with 1000 spectral bins in the 580- to 950-nm range over a wide, scalable field of view. With an average accuracy of 6.7% and 12.3% in and , respectively, compared to conventional methods, hs-SFDI offers a promising approach for quantitative hyperspectral tissue optical imaging.

Highlights

Biomedical hyperspectral imaging (HSI) combines high-resolution spectral and spatial content, in order to characterize tissue structure and composition
To experimentally validate the performance of the broadband hyperspectral imager, we performed a series of controlled tissue phantom measurements to demonstrate that the instrument can quantify absorption and reduced scattering over a wide spectral range
Turbid versions of the same solutions were prepared by adding intralipid (IL) (Fresenius Kabi, Uppsala, Sweden): one milliliter of 20% IL was added to 19 mL of each solution, poured into the wells of the phantom, and measured with the hyperspectral Spatial frequency domain imaging (SFDI) instrument

Summary

Introduction

Biomedical hyperspectral imaging (HSI) combines high-resolution spectral and spatial content, in order to characterize tissue structure and composition. Because HSI typically employs hundreds or thousands of optical wavelengths, multiple endogenous and exogenous tissue components with unique spectral signatures can be resolved. Various HSI technical approaches have been developed for biomedical applications—most based on designs that generate reflectance and/or fluorescence maps over a continuous spectral bandwidth.[1,2,3] Hyperspectral content can be used in conjunction with computational models of light transport and various statistical methods, such as principal component analysis, to calculate optical and physiological properties for each pixel.[4,5,6] these methods generally require assumptions or approximations about certain tissue features, such as scattering properties and water concentration.[7,8] Unlike temporally or spatially resolved approaches, they do not independently separate and map subsurface tissue absorption and reduced scattering parameters, μa and μs[0], respectively, for each wavelength and pixel.[9] Changes in each of these parameters occur with spatial and temporal variations in tissue molecular composition and structure. Quantitatively characterizing these light–tissue interactions over a broad spectral range with high temporal resolution can be important in accurately recovering dynamics of multiple endogenous and exogenous tissue chromophores.[10,11]

Methods

Results

Discussion

Conclusion