Multispectral multiple-scattering low-coherence interferometry (ms2/LCI) exploits forward scattered light to enable imaging depths of up to several mm in tissue with mm resolution in the transverse dimension and 0.1 mm depth resolution.
This technique uses both spatial and coherence gating to restrict the detected photon paths and achieve imaging depths of up to 90 scattering mean free paths (MFPs). This is a significant improvement over confocal microscopy and optical coherence tomography, where the imaging ranges are limited to ~ 3 and ~ 27 MFPs respectively.
Our current system exploits frequency domain detection to reduce data acquisition times and determine the spectroscopic properties of the sample. Fourier domain interferograms are acquired and processed using time-frequency analysis techniques such as the Short Time Fourier Transform (STFT) or the recently developed Dual Window (DW) method to yield depth-gated reflectance spectra. Such spectroscopic analysis enables localization of sub-surface chromophores such as blood vessels and identification of other tissue components (bone, cartilage).
Howard Levinson, MD