Multispectral imaging of tissue absorption and scattering using spatial frequency domain imaging and a computed-tomography imaging spectrometer

• Published in: Journal of Biomedical Optics Vol. 16; no. 1; p. 011015
• Main Authors: Weber, Jessie R, Durkin, Anthony J, Tromberg, Bruce J, Cuccia, David J, Johnson, William R, Wilson, Daniel W, Bearman, Gregory H, Hsu, Mike, Lin, Alexander, Binder, Devin K
• Format: Journal Article
• Language: English
• Published: United States Society of Photo-Optical Instrumentation Engineers (SPIE) 01.01.2011
• Subjects: Animals; Brain Chemistry; Brain Injuries - diagnosis; Charge coupled devices; Equipment Design; Equipment Failure Analysis; Frequency domains; Imaging; Imaging spectrometers; Mice; Nephelometry and Turbidimetry - instrumentation; Oxygen - analysis; Phantoms, Imaging; Platforms; Reproducibility of Results; Scattering; Sensitivity and Specificity; Special Section on Pioneers in Biomedical Optics: Michael Feld; Spectra; Spectrum Analysis - instrumentation; Systems Integration; Tomography, X-Ray Computed - instrumentation
• ISSN: 1083-3668; 1560-2281
• DOI: 10.1117/1.3528628

We present an approach for rapidly and quantitatively mapping tissue absorption and scattering spectra in a wide-field, noncontact imaging geometry by combining multifrequency spatial frequency domain imaging (SFDI) with a computed-tomography imaging spectrometer (CTIS). SFDI overcomes the need to spatially scan a source, and is based on the projection and analysis of periodic structured illumination patterns. CTIS provides a throughput advantage by simultaneously diffracting multiple spectral images onto a single CCD chip to gather spectra at every pixel of the image, thus providing spatial and spectral information in a single snapshot. The spatial-spectral data set was acquired 30 times faster than with our wavelength-scanning liquid crystal tunable filter camera, even though it is not yet optimized for speed. Here we demonstrate that the combined SFDI-CTIS is capable of rapid, multispectral imaging of tissue absorption and scattering in a noncontact, nonscanning platform. The combined system was validated for 36 wavelengths between 650-1000 nm in tissue simulating phantoms over a range of tissue-like absorption and scattering properties. The average percent error for the range of absorption coefficients ( a) was less than 10% from 650-800 nm, and less than 20% from 800-1000 nm. The average percent error in reduced scattering coefficients ( s′) was less than 5% from 650-700 nm and less than 3% from 700-1000 nm. The SFDI-CTIS platform was applied to a mouse model of brain injury in order to demonstrate the utility of this approach in characterizing spatially and spectrally varying tissue optical properties.