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Purpose:In glioma surgery, it is critical to maximize tumor resection without compromising adjacent noncancerous brain tissue. Optical coherence tomography (OCT) is a noninvasive, label-free, real-time, high-resolution imaging modality that has been explored for glioma infiltration detection. Here, we report a novel artificial intelligence (AI)-assisted method for automated, real-time, in situ detection of glioma infiltration at high spatial resolution.Experimental Design: Volumetric OCT datasets were intraoperatively obtained from resected brain tissue specimens of 21 patients with glioma tumors of different stages and labeled as either noncancerous or glioma-infiltrated on the basis of histopathology evaluation of the tissue specimens (gold standard). Labeled OCT images from 12 patients were used as the training dataset to develop the AI-assisted OCT-based method for automated detection of glioma-infiltrated brain tissue. Unlabeled OCT images from the other 9 patients were used as the validation dataset to quantify the method detection performance.Results:Our method achieved excellent levels of sensitivity (∼100%) and specificity (∼85%) for detecting glioma-infiltrated tissue with high spatial resolution (16 μm laterally) and processing speed (∼100,020 OCT A-lines/second).Conclusions:Previous methods for OCT-based detection of glioma-infiltrated brain tissue rely on estimating the tissue optical attenuation coefficient from the OCT signal, which requires sacrificing spatial resolution to increase signal quality, and performing systematic calibration procedures using tissue phantoms. By overcoming these major challenges, our AI-assisted method will enable implementing practical OCT-guided surgical tools for continuous, real-time, and accurate intraoperative detection of glioma-infiltrated brain tissue, facilitating maximal glioma resection and superior surgical outcomes for patients with glioma.

Sweep animation for a predicted cancer-free OCT volume

Sweep animation for a predicted cancer-infiltrated OCT volume

Rotation animation of a predicted cancer-infiltrated OCT volume

This document contains suplementary data (Figure S1, Figure S2, Table S1, and Table S2). Each of these Figures and Tables has a detailed explanation for their calculations

Rotation animation of a predicted cancer-free OCT volume

Purpose: In glioma surgery, it is critical to maximize tumor resection without compromising adjacent noncancerous brain tissue. Optical coherence tomography (OCT) is a noninvasive, label-free, real-time, high-resolution imaging modality that has been explored for glioma infiltration detection. Here, we report a novel artificial intelligence (AI)-assisted method for automated, real-time, in situ detection of glioma infiltration at high spatial resolution. Experimental Design: Volumetric OCT datasets were intraoperatively obtained from resected brain tissue specimens of 21 patients with glioma tumors of different stages and labeled as either noncancerous or glioma-infiltrated on the basis of histopathology evaluation of the tissue specimens (gold standard). Labeled OCT images from 12 patients were used as the training dataset to develop the AI-assisted OCT-based method for automated detection of glioma-infiltrated brain tissue. Unlabeled OCT images from the other 9 patients were used as the validation dataset to quantify the method detection performance. Results: Our method achieved excellent levels of sensitivity (∼100%) and specificity (∼85%) for detecting glioma-infiltrated tissue with high spatial resolution (16 μm laterally) and processing speed (∼100,020 OCT A-lines/second). Conclusions: Previous methods for OCT-based detection of glioma-infiltrated brain tissue rely on estimating the tissue optical attenuation coefficient from the OCT signal, which requires sacrificing spatial resolution to increase signal quality, and performing systematic calibration procedures using tissue phantoms. By overcoming these major challenges, our AI-assisted method will enable implementing practical OCT-guided surgical tools for continuous, real-time, and accurate intraoperative detection of glioma-infiltrated brain tissue, facilitating maximal glioma resection and superior surgical outcomes for patients with glioma.

PURPOSE: In glioma surgery, it is critical to maximize tumor resection without compromising adjacent non-cancerous brain tissue. Optical Coherence Tomography (OCT) is a non-invasive, label-free, real-time, high-resolution imaging modality that has been explored for glioma infiltration detection. Here we report a novel artificial intelligence (AI) assisted method for automated, real-time, in situ detection of glioma infiltration at high spatial resolution. EXPERIMENTAL DESIGN: Volumetric OCT datasets were intraoperatively obtained from resected brain tissue specimens of 21 patients with glioma tumors of different stages and labeled as either non-cancerous or glioma-infiltrated based on histopathology evaluation of the tissue specimens (gold standard). Labeled OCT images from 12 patients were used as the training dataset to develop the AI assisted OCT-based method for automated detection of glioma-infiltrated brain tissue. Unlabeled OCT images from the other 9 patients were used as the validation dataset to quantify the method detection performance. RESULTS: Our method achieved excellent levels of sensitivity (~100%) and specificity (~85%) for detecting glioma-infiltrated tissue with high spatial resolution (16 μm laterally) and processing speed (~100,020 OCT A-lines/second). CONCLUSIONS: Previous methods for OCT-based detection of glioma-infiltrated brain tissue rely on estimating the tissue optical attenuation coefficient from the OCT signal, which requires sacrificing spatial resolution to increase signal quality, and performing systematic calibration procedures using tissue phantoms. By overcoming these major challenges, our AI-assisted method will enable implementing practical OCT-guided surgical tools for continuous, real-time and accurate intra-operative detection of glioma-infiltrated brain tissue, facilitating maximal glioma resection and superior surgical outcomes for glioma patients.

Transient receptor potential A1 (TRPA1) is a newly defined cationic ion channel, which selectively expresses in primary sensory afferent nerve, and is essential in mediating inflammatory nociception. Our previous study demonstrated that TRPA1 plays an important role in tissue mast cell activation-induced increase in the excitability of esophageal vagal nodose C fibers. The present study aims to determine whether prolonged antigen exposure in vivo sensitizes TRPA1 in a guinea pig model of eosinophilic esophagitis (EoE). Antigen challenge-induced responses in esophageal mucosa were first assessed by histological stains and Ussing chamber studies. TRPA1 function in vagal sensory neurons was then studied by calcium imaging and by whole cell patch-clamp recordings in 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (DiI)-labeled esophageal vagal nodose and jugular neurons. Extracellular single-unit recordings were performed in vagal nodose and jugular C-fiber neuron subtypes using ex vivo esophageal-vagal preparations with intact nerve endings in the esophagus. Antigen challenge significantly increased infiltrations of eosinophils and mast cells in the esophagus. TRPA1 agonist allyl isothiocyanate (AITC)-induced calcium influx in nodose and jugular neurons was significantly increased, and current densities in esophageal DiI-labeled nodose and jugular neurons were also significantly increased in antigen-challenged animals. Prolonged antigen challenge decreased esophageal epithelial barrier resistance, which allowed intraesophageal-infused AITC-activating nodose and jugular C fibers at their nerve endings. Collectively, these results demonstrated that prolonged antigen challenge sensitized TRPA1 in esophageal sensory neurons and afferent C fibers. This novel finding will help us to better understand the molecular mechanism underlying esophageal sensory and motor dysfunctions in EoE.

Speckle resides in OCT signals and inevitably effects OCT image quality. In this work, we present a novel method for speckle noise reduction in Fourier-domain OCT images, which utilizes the phase information of complex OCT data. In this method, speckle area is pre-delineated pixelwise based on a phase-domain processing method and then adjusted by the results of wavelet shrinkage of the original image. Coefficient shrinkage method such as wavelet or contourlet is applied afterwards for further suppressing the speckle noise. Compared with conventional methods without speckle adjustment, the proposed method demonstrates significant improvement of image quality.

Prostate cancer is highly heterogeneous in nature; while the majority of cases are clinically insignificant, some cases are lethal. Currently, there are no reliable screening methods for aggressive prostate cancer. Since most established serum and urine biomarkers are glycoproteins secreted or leaked from the diseased tissue, the current study seeks to identify glycoprotein markers specific to aggressive prostate cancer using tissue specimens. With LC-MS/MS glycoproteomic analysis, we identified 350 glycopeptides with 17 being altered in aggressive prostate cancer. ELISA assays were developed/purchased to evaluate four candidates, that is, cartilage oligomeric matrix protein (COMP), periostin, membrane primary amine oxidase (VAP-1), and cathepsin L, in independent tissue sets. In agreement with the proteomic analysis, we found that COMP and periostin expressions were significantly increased in aggressive prostate tumors while VAP-1 expression was significantly decreased in aggressive tumor. In addition, the expression of these proteins in prostate metastases also follows the same pattern observed in the proteomic analysis. This study provides a workflow for biomarker discovery, prioritization, and evaluation of aggressive prostate cancer markers using tissue specimens. Our data suggest that increase in COMP and periostin and decrease in VAP-1 expression in the prostate may be associated with aggressive prostate cancer.

We present an all-fiber-optically based endoscope platform for simultaneous optical coherence tomography (OCT) and fluorescence imaging. This design entails the use of double-clad fiber (DCF) in the endoscope for delivery of OCT source and fluorescence excitation light while collecting the backscattered OCT signal through the single-mode core and fluorescence emission through the large inner cladding of the DCF. Circumferential beam scanning was performed by rotating a 45° reflector using a miniature DC motor at the distal end of the endoscope. Additionally, a custom DCF coupler and a wavelength division multiplexer (WDM) were utilized to seamlessly integrate both imaging modalities to achieve an entirely fiber-optically based dual-modality imaging system. We demonstrated simultaneous intraluminal 3D OCT and 2D (surface) fluorescence imaging in ex vivo rabbit esophagus using the dual-modal endomicroscopy system. Structural morphologies (provided by OCT) and fluorophore distribution (provided by the fluorescence module) could be clearly visualized, suggesting the potential of the dual-modality system for future in vivo and clinical applications.

Fine optical coherence tomography (OCT) imaging needles that can be integrated with a standard biopsy needle have been developed with a new optics design to improve the optical quality and mechanical robustness, where a fiber-optic lens (that is spliced to a single-mode fiber) and a microreflector are encased within a microglass tube. The design also minimizes the cylindrical lens effect induced by the glass tube and eases the needle assembly process. Real-time cross-sectional OCT imaging of various tissue samples were performed ex vivo using the miniature-imaging needle along with a 1300-nm swept-source OCT system. The preliminary results demonstrate the improved mechanical and optical performance and suggest the potential of the fine OCT needle for minimally invasive interstitial imaging and image-guided biopsy.

We developed a universal, real-time uniform K-space sampling (Rt-UKSS) method for high-speed swept-source optical coherence tomography (SS-OCT). An external clock uniform in K-space was generated. The clock was synchronized with the zero-crossing time of an interferometric calibration signal and used as triggers for a high-speed data acquisition system in a point-by-point fashion, hence enabling uniform data sampling in K-space. Different from the numerical calibration algorithm commonly used in an SS-OCT system, the method reported here does not require over-sampling, thus greatly reducing the demand for digitization, data processing and storage speed. The Rt-UKSS method is adaptive and applicable to a generic SS-OCT system of a wide range of A-scan rates without special adjustment. We successfully implemented the Rt-UKSS method in an SS-OCT system based on a Fourier-domain mode-locked laser (FDML) of a 40-kHz scanning rate. Real-time imaging of biological tissues using such a system was demonstrated with a measured axial resolution of 9.3 mum and detection sensitivity greater than 120dB.

Finite difference time domain (FDTD) method is adopted to build a Bessel beams simulation model according to homogeneousness and linearity of the Maxwell equations in source-free region. Validation for this model is confirmed by comparing the simulation results with the theoretical results solved with a vector Helmholtz equation in free space and good agreement with maximum error 2% has been demonstrated. It is indicated that FDTD could be an effective approach to analyze other complicated models of Bessel beams in source-free region by means of superposition principle.

More complete brain cancer resection can prolong survival and delay recurrence. However, it is challenging to distinguish cancer from noncancer tissues intraoperatively, especially at the transitional, infiltrative zones. This is especially critical in eloquent regions (for example, speech and motor areas). This study tested the feasibility of label-free, quantitative optical coherence tomography (OCT) for differentiating cancer from noncancer in human brain tissues. Fresh ex vivo human brain tissues were obtained from 32 patients with grade II to IV brain cancer and 5 patients with noncancer brain pathologies. On the basis of volumetric OCT imaging data, pathologically confirmed brain cancer tissues (both high- and low-grade) had significantly lower optical attenuation values at both cancer core and infiltrated zones when compared with noncancer white matter, and OCT achieved high sensitivity and specificity at an attenuation threshold of 5.5 mm(-1) for brain cancer patients. We also used this attenuation threshold to confirm the intraoperative feasibility of performing in vivo OCT-guided surgery using a murine model harboring human brain cancer. Our OCT system was capable of processing and displaying a color-coded optical property map in real time at a rate of 110 to 215 frames per second, or 1.2 to 2.4 s for an 8- to 16-mm(3) tissue volume, thus providing direct visual cues for cancer versus noncancer areas. Our study demonstrates the translational and practical potential of OCT in differentiating cancer from noncancer tissue. Its intraoperative use may facilitate safe and extensive resection of infiltrative brain cancers and consequently lead to improved outcomes when compared with current clinical standards.

Realization of a near-field optical virtual probe based on an evanescent Bessel beam is strongly dependent on a radially polarized beam; this makes it essential to study the focusing property of the beam. In this paper, two experimental setups based on a fiber device and a liquid crystal device, respectively, are built to generate a radially polarized beam. This beam and an annular radially polarized beam are focused by means of a high numerical aperture objective and a solid immersion lens (SIL). Near-field distribution of the focus spot, the evanescent Bessel field, is experimentally measured with a scanning near-field optical microscope (SNOM). The full width at half maximum (FWHM) of the central peak of the evanescent Bessel field is about 200 nm in the close vicinity of the bottom surface of SIL. This has potential for use as a near-field optical virtual probe.

This paper describes an endoscopic-inspired imaging system employing a micro-electromechanical system (MEMS) micromirror scanner to achieve beam scanning for optical coherence tomography (OCT) imaging. Miniaturization of a scanning mirror using MEMS technology can allow a fully functional imaging probe to be contained in a package sufficiently small for utilization in a working channel of a standard gastroesophageal endoscope. This work employs advanced image processing techniques to enhance the images acquired using the MEMS scanner to correct non-idealities in mirror performance. The experimental results demonstrate the effectiveness of the proposed technique.

We presented a new OCT endoscope design for ultrahigh-resolution 3D imaging at 800nm by using a diffractive microlens for chromatic aberration management. The performance of the OCT imaging catheter was demonstrated by in vivo experiments

This study uses OCT and optical property mapping to detect brain tumors in vivo in mice bearing human glioblastoma and in fresh ex vivo brain tissues from 32 patients with high sensitivity and specificity.

We presented a new speckle detection and reduction method using phase-domain information of OCT signals. Speckle noise was reduced by adjusting the speckles and wavelet shrinkage. Good improvement of image quality was observed.

We report recent progresses in the fiber-optic multiphoton endomicroscopy technology. High-quality two-photon images of unstained biological tissues along with potential clinical applications are presented.

We investigated the optimal operational conditions for utilizing a broadband supercontinuum (SC) source in a portable 800 nm spectral-domain (SD) endoscopic OCT system to enable high resolution, high-sensitivity, and high-speed imaging in vivo. A SC source with a 3-dB bandwidth of ∼246 nm was employed to obtain an axial resolution of ∼2.7 μm (in air) and an optimal detection sensitivity of ∼-107 dB with an imaging speed up to 35 frames/s (at 70 k A-scans/s). The performance of the SC-based SD-OCT endoscopy system was demonstrated by imaging guinea pig esophagus in vivo, achieving image quality comparable to that acquired with a broadband home-built Ti:sapphire laser.

We report the development of an all-fiber-optic scanning endomicroscope capable of high-resolution second harmonic generation (SHG) imaging of biological tissues and demonstrate its utility for monitoring the remodeling of cervical collagen during gestation in mice. The endomicroscope has an overall 2.0 mm diameter and consists of a single customized double-clad fiber, a compact rapid two-dimensional beam scanner, and a miniature compound objective lens for excitation beam delivery, scanning, focusing, and efficient SHG signal collection. Endomicroscopic SHG images of murine cervical tissue sections at different stages of normal pregnancy reveal progressive, quantifiable changes in cervical collagen morphology with resolution similar to that of bench-top SHG microscopy. SHG endomicroscopic imaging of ex vivo murine and human cervical tissues through intact epithelium has also been performed. Our findings demonstrate the feasibility of SHG endomicroscopy technology for staging normal pregnancy, and suggest its potential application as a minimally invasive tool for clinical assessment of abnormal cervical remodeling associated with preterm birth.

Ex vivo human brain tissues from 8 glioma patients and 5 controls are imaged using SS-OCT, with higher glioma attenuation values and easily detectable and specific tumor features (microcyst, necrosis and pallisading) for intraoperative resections.

Using an acousto-optic modulator that froze beam positions on frames captured by an ordinary CCD camera, we were able to calibrate the Lissajous scanning pattern on a fiber-optic nonlinear endomicroscope quickly and precisely.

We investigated the feasibility of a high-speed SS-OCT system along with a miniature side-viewing catheter to dynamically assess structures of the bronchus in vivo. Excellent correlations were achieved between OCT images and the corresponding histology.

An all-fiber-optically based balloon catheter for simultaneous fluorescence imaging and OCT has been implemented. The performance of this multimodal catheter is demonstrated on tissue phantom, ex vivo pig esophagus and mouse tumor imaging.

A miniature fiber optic endomicroscope with built-in dynamic focus scanning capability is developed for the first time for 3-D two-photon fluorescence (TPF) imaging of biological samples. Fast 2-D lateral beam scan- ning is realized by resonantly vibrating a double-clad fiber cantilever with a tubular piezoactuator. Slow axial scan- ning is achieved by moving the distal end of the imaging probe with an extremely compact electrically driven shape memory alloy (SMA). The 10-mm-long SMA allows 150- μm contractions with a driving voltage varying only from 50 to 100 mV. The response of the SMA contraction with the applied voltage is nonlinear, but repeatable and can be ac- curately calibrated. Depth-resolved imaging of acriflavine- stained biological tissues and unstained white paper with the endomicroscope is performed, and the results demon- strate the feasibility of 3-D nonlinear optical imaging with the SMA-based scanning fiber-optic endomicroscope. C 2010

We report on our recent developments of optical coherence tomography endoscopy technologies that enable aberration correction, high-speed uniform data acquisition in Fourier domain, and functional integration with multiphoton fluorescence imaging.

We present updates on recent developments of a fully integrated, ultracompact fiberoptic scanning endomicroscope for nonlinear optical imaging. Approaches to significantly improve signal collection efficiency and resolution will be discussed.

This paper reviews our recent developments of ultrathin fiber-optic endomicroscopy technologies for transforming high-resolution noninvasive optical imaging techniques to in vivo and clinical applications such as early disease detection and guidance of interventions. Specifically we describe an all-fiber-optic scanning endomicroscopy technology, which miniaturizes a conventional bench-top scanning laser microscope down to a flexible fiber-optic probe of a small footprint (i.e. ~2-2.5 mm in diameter), capable of performing two-photon fluorescence and second harmonic generation microscopy in real time. This technology aims to enable realtime visualization of histology in situ without the need for tissue removal. We will also present a balloon OCT endoscopy technology which permits high-resolution 3D imaging of the entire esophagus for detection of neoplasia, guidance of biopsy and assessment of therapeutic outcome. In addition we will discuss the development of functional polymeric fluorescent nanocapsules, which use only FAD approved materials and potentially enable fast track clinical translation of optical molecular imaging and targeted therapy.

Gold nanocages were synthesized to shift the surface plasmon resonance peak to ~900 nm. We demonstrate these nanocages can be used as contrast agents for conventional and spectroscopic OCT at 1060 nm.

We report a discrete-frequency Fourier domain mode-locked (DF-FDML) laser with uniform k-space distribution for OCT imaging. The uniform-k discrete frequencies were generated by incorporating a Fabry-Perot interferometer inside a conventional FDML cavity. OCT imaging of biological tissues was demonstrated using a prototype FD-FDML with 10mW output power, 20 kHz scanning rate, −110dB sensitivity and 12 µm axial resolution. The sensitivity exhibited no degradation throughout a ranging depth of 6 mm.

A forward-viewing fiber-optic endoscope was developed with the scanning speed appropriate for 3-D real-time OCT imaging when using a high-speed swept source. The scanning speed was systematically analyzed. In-vivo 3-D oral cavity imaging was performed.

We demonstrated a real-time calibration method for high-speed SS-OCT. An external clock was generated to trigger the high-speed data acquisition system point by point and enable uniform data sampling in frequency domain (K-space).

We report on a fiber-optic scanning endomicroscopy system based on a customized double-clad fiber (DCF) and a miniature compound lens that enables two-photon autofluorescence imaging of biological tissues for the first time.

An extremely compact all-fiber-optic scanning endomicroscopy system was developed for two-photon fluorescence (TPF) and second harmonic generation (SHG) imaging of biological samples. A conventional double-clad fiber (DCF) was employed in the endomicroscope for single-mode femtosecond pulse delivery, multimode nonlinear optical signals collection and fast two-dimensional scanning. A single photonic bandgap fiber (PBF) with negative group velocity dispersion at two-photon excitation wavelength (i.e. approximately 810 nm) was used for pulse prechirping in replacement of a bulky grating/lens-based pulse stretcher. The combined use of DCF and PBF in the endomicroscopy system made the endomicroscope basically a plug-and-play unit. The excellent imaging ability of the extremely compact all-fiber-optic nonlinear optical endomicroscopy system was demonstrated by SHG imaging of rat tail tendon and depth-resolved TPF imaging of epithelial tissues stained with acridine orange. The preliminary results suggested the promising potential of this extremely compact all-fiber-optic endomicroscopy system for real-time assessment of both epithelial and stromal structures in luminal organs.

This paper reports on our recent development of two-types of all-fiber-optic scanning endomicroscopy technologies for high-resolution optical imaging of internal organs. The first one is an OCT balloon catheter technology that permits systematic imaging of fine architectural morphologies of internal luminal organs over a large area. The second is a two-photon fluorescence endomicroscopy technology that enables assessment of tissue biochemical/metabolic information with a superb spatial resolution. Both endomicroscopes have a small diameter (1.2–2.4 mm) and can be readily integrated with a standard clinical gastroscope, providing complementary information about tissue structure and function and helping improve diagnostic yield. We will discuss the basic design principles, major engineering challenges, solutions, and some preliminary results. In addition, we will also present our approach in developing near infrared (NIR) fluorescent nanocomplexes (ICG-micelles), which can be functionalized for active molecular targeting to improve molecular specificity and imaging contrast. These nanocomplexes, made of FDA approved building blocks, are biocompatible and very promising for clinical translation. Ultimately the NIR nanocomplexes can be used in conjunction with endomicroscopy technologies for performing high-resolution optical molecular imaging in vivo and in real time.

A flexible fiber-optic endomicroscopy system was developed for nonlinear optical imaging of biological samples. Double-clad fiber and photonic bandgap fiber were employed in the endomicroscope for femtosecond pulse delivery, dispersion compensation, nonlinear optical signals collection and fast beam scanning. Three-dimensional imaging of biological tissues based on second harmonic generation and two-photon excited fluorescence was performed with the endomicroscope. The depth-resolved imaging results strongly suggest the potential of this flexible fiber-optic microscope system for real-time assessment of both epithelial and stromal structures in luminal organs.

An endomicroscope with enhanced signal collection efficiency was developed using customized double-clad fiber and aspherical compound-lens. Ex vivo two-photon fluorescence imaging of epithelial tissues was demonstrated for the first time with an all-fiber-optic scanning endomicroscope.

Gold nanocages with a relatively small size (e.g., approximately 45 nm in edge length) have been developed, and the structure of these nanocages was tailored to achieve strong absorption in the near-infrared (NIR) region for photothermal cancer treatment. Numerical calculations show that the nanocage has a large absorption cross section of 3.48 x 10(-14) m(2), facilitating conversion of NIR irradiation into heat. The gold nanocages were conjugated with monoclonal antibodies (anti-HER2) to target epidermal growth factor receptors (EGFR) that are overexpressed on the surface of breast cancer cells (SK-BR-3). Our preliminary photothermal results show that the nanocages strongly absorb light in the NIR region with an intensity threshold of 1.5 W/cm(2) to induce thermal destruction to the cancer cells. In the intensity range of 1.5-4.7 W/cm(2), the circular area of damaged cells increased linearly with the irradiation power density. These results suggest that this new class of bioconjugated gold nanostructures, immuno gold nanocages, can potentially serve as an effective photothermal therapeutic agent for cancer treatment.

A near-field optical virtual probe based on the principle of near-field evanescent wave interference can be used in optical data storage, nano-lithography, near-field imaging and optical manipulation etc. The best choice of evanescent wave interference is evanescent Bessel beams that have the characteristics of both propagating Bessel beams and evanescent wave. It is concluded that evanescent Bessel beams is an evanescent wave with the characteristics of diffraction free and radial polarization. These characteristics lead to several advantages in near-field optics: the focus of radially polarized light can be quite smaller than the one of linear polarized light used commonly and diffraction free can bring in constant intensity distribution in a certain range. Meanwhile, based on the concept of conventional apodization, the idea of apodization of evanescent field is proposed to overcome some disadvantages of evanescent Bessel beams, such as the big side lobe and spread of transversal intensity. In this paper, Finite Difference Time Domain (FDTD) method is adopted to simulate the evanescent Bessel beams. Several parameters are considered as variants changeable to get the different simulation results. The better performance of the side lobe suppression and the narrow spot size are discussed. This work may be important to the application of near-field optical virtual probe in the future.

We present a generic phase-domain processing method for detecting speckles in Fourier-domain optical coherence tomography (OCT) images. The physics behind the interferometry is revisited and analytically along with simulation results it indicates that the speckle formation comes with phase distortion to the complex OCT signal. The first and the second derivatives of phase along the imaging depth are then calculated for speckle identification. The phase-domain processing method was applied to images acquired by both spectral-domain OCT and swept-source OCT systems, and the experimental results show that this method enables pixel-wise speckle identification.

Background: Neuro-immune interaction has evolved as an integral part in the pathophysiology of gut and crosstalk between nerves andmast cells is a typical example of such interactions. We have already reported that CGRP-immunoreactive intrinsic nerve fibers are specifically increased along with the development of food allergy in the colonic mucosa of our food allergy model mice. Furthermore, our previous studies have provided vivid evidences of mucosal mast cells (MMCs) juxtaposed with CGRP-positive enteric nerve fibers in the colonic mucosa of food allergy model mice. IgE-antigen stimulation has not only documented to cause degranulation in mast cells but also, recently, reported to cause activation of neurons in superior cervical ganglion. However, no study so far employed isolated enteric neurons and MMCs to elaborate this interaction which closely mimics to the pathophysiological state of the gut in the allergic condition. In the present study, we cultured both isolated enteric neurons and MMCs and examine their interaction. Material & methods: Enteric neurons were isolated from small intestine of BALB/c (4 to 6 weeks old) and examined by anti-β3tubulin antibody (anti-pan-neuronal marker antibody). Presence of high-affinity IgE receptors (FceRIs) on myentric neurons was examined in longitudinal muscle/myenteric plexus (LMMP) preparations by immunohistochemistry (IHC). Mucosal type bone marrow-derived mast cells (mBMMCs) were prepared from the femurs of BALB/c mice using four cytokines (SCF, IL-3, IL-9 and TGF-β1) and degranulation was performed by incubation with IgEantigen (IgE-DNP) to give mast cell juice (MCJ). Isolated enteric neurons were stimulated with either IgE-DNP or MCJ and analyzed by calcium imaging using fluo-8, a fluorescent calcium indicator. Finally, isolated enteric neurons were co-incubated with IgE-pretreated mBMMCs followed by stimulation with DNP. Only isolated enteric neurons were loaded with Fluo-8. Results: IHC studies revealed the presence of FceRI on the cell body of myentric neurons. Stimulation of isolated enteric neurons with IgE-DNP demonstrated an increase in intracellular calcium concentration ([Ca2+]i). Similarly, treatment of isolated enteric neurons with MCJ also led to an increase in [Ca2+]i. Furthermore, stimulation with DNP in an isolated enteric neuron/IgE-pretreated mBMMC co-culture condition produced an elevation of [Ca2+]i in isolated enteric neurons. Conclusion: We demonstrated here for the first time the activation of isolated enteric neurons by IgE-antigen, MCJ, and activated mBMMCs via calcium imaging. Therefore, we infer both direct and indirect involvement of crosstalk between enteric neurons and mucosal mast cells in allergic and inflammatory/ functional diseases of gut like food allergy or irritable bowel syndrome.