Design and validation of an angle-resolved low-coherence interferometry fiber probe for in vivo clinical measurements of depth-resolved nuclear morphology

Abstract

Abstract. We present a novel Fourier-domain angle-resolved low-coherence interferometry (a /LCI) fiber probe designed for in vivo clinical application in gastrointestinal endoscopy. The a/LCI technique measures the depthresolved angular scattering distribution to determine the size distribution and optical density of cell nuclei for assessing the health of epithelial tissues. Clinical application is enabled by an endoscopic fiber-optic probe that employs a 2.3-m-long coherent fiber bundle and is compatible with the standard 2.8-mm-diam biopsy channel of a gastroscope. The probe allows for real-time data acquisition by collecting the scattering from multiple angles in parallel, enabled by the Fourier domain approach. The performance of the probe is characterized through measurement of critical parameters. The depth-resolved sizing capability of the system is demonstrated using single-and double-layer microsphere phantoms with subwavelength sizing precision and accuracy achieved. Initial results from a clinical feasibility test are also presented to show in vivo application in the human esophagus. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

Numerical investigation of two-dimensional light scattering patterns of cervical cell nuclei to map dysplastic changes at different epithelial depths

“…Overall, the results presented corroborate the fact that a depth-specific analysis is necessary to fully map the scattering properties of epithelial tissues [4,31,32]. While previous studies have revealed a layer-to-layer variation in scattering strength, a similar trend is also evident here for other intensity and shape metrics computed from two-dimensional patterns.…”

Evaluation of hybrid algorithm for analysis of scattered light using ex vivo nuclear morphology measurements of cervical epithelium

“…a/LCI clinical system schematic in a Mach-Zehnder interferometer geometry. The fiber probe tip shows the sample illumination by the PM fiber and scattered light collected through the fiber bundle [17].…”

“…1 and described in detail by Zhu, et al [17]. Briefly, an 830 nm superluminescent diode (Superlum, Moscow, Russia) is used in a Mach-Zehnder interferometer geometry.…”

Co-localized confocal Raman spectroscopy and optical coherence tomography (CRS-OCT) for depth-resolved analyte detection in tissue

“…These measurements were subracted from all subsequent ones in order to isolate the interference term. Next, the interference spectrum was remapped onto a linear wavenumber axis and a phase correction was applied to compensate for any dispersion imbalance between the sample and reference arms [22,23]. Finally, the processed interference spectrum was Fourier transformed to determine the depth-resolved reflectivity of the sample.…”