Rapid head and neck tissue identification in thyroid and parathyroid surgery using optical coherence tomography.

Background: Optical coherence tomography (OCT) is a noninvasive imaging modality that may reproduce the microarchitecture of tissues in real-time. This study examines whether OCT can render distinct images of thyroid, parathyroid glands, adipose tissue, and lymph nodes in both healthy and pathological states.

Methods: Twenty-seven patients undergoing thyroidectomy, parathyroidectomy, and/or neck dissection for thyroid cancer were recruited prospectively for imaging prior to histopathological analysis.

Development and characterization of a handheld hyperspectral Raman imaging probe system for molecular characterization of tissue on mesoscopic scales.

Purpose: Raman spectroscopy is a promising cancer detection technique for surgical guidance applications. It can provide quantitative information relating to global tissue properties associated with structural, metabolic, immunological, and genetic biochemical phenomena in terms of molecular species including amino acids, lipids, proteins, and nucleic acid (DNA). To date in vivo Raman spectroscopy systems mostly included probes and biopsy needles typically limited to single-point tissue interrogation over a scale between 100 and 500 microns.

Dimension reduction technique using a multilayered descriptor for high-precision classification of ovarian cancer tissue using optical coherence tomography: a feasibility study.

Optical coherence tomography (OCT) yields microscopic volumetric images representing tissue structures based on the contrast provided by elastic light scattering. Multipatient studies using OCT for detection of tissue abnormalities can lead to large datasets making quantitative and unbiased assessment of classification algorithms performance difficult without the availability of automated analytical schemes. We present a mathematical descriptor reducing the dimensionality of a classifier's input data, while preserving essential volumetric features from reconstructed three-dimensional optical volumes.

Morphologic three-dimensional scanning of fallopian tubes to assist ovarian cancer diagnosis.

The majority of high-grade serous ovarian cancers is now believed to originate in the fallopian tubes. Therefore, current practices include the pathological examination of excised fallopian tubes. Detection of tumors in the fallopian tubes using current clinical approaches remains difficult but is of critical importance to achieve accurate staging and diagnosis.

A review of Raman spectroscopy advances with an emphasis on clinical translation challenges in oncology.

There is an urgent need for improved techniques for disease detection. Optical spectroscopy and imaging technologies have potential for non- or minimally-invasive use in a wide range of clinical applications. The focus here, in vivo Raman spectroscopy (RS), measures inelastic light scattering based on interaction with the vibrational and rotational modes of common molecular bonds in cells and tissue.

Tri-modal microscope for head and neck tissue identification.

A novel tri-modal microscope combining optical coherence tomography (OCT), spectrally encoded confocal microscopy (SECM) and fluorescence imaging is presented. This system aims at providing a tool for rapid identification of head and neck tissues during thyroid surgery. The development of a dual-wavelength polygon-based swept laser allows for synchronized, co-registered and simultaneous imaging with all three modalities.

Molecular imaging needles: dual-modality optical coherence tomography and fluorescence imaging of labeled antibodies deep in tissue.

Molecular imaging using optical techniques provides insight into disease at the cellular level. In this paper, we report on a novel dual-modality probe capable of performing molecular imaging by combining simultaneous three-dimensional optical coherence tomography (OCT) and two-dimensional fluorescence imaging in a hypodermic needle. The probe, referred to as a molecular imaging (MI) needle, may be inserted tens of millimeters into tissue.

Double-clad fiber coupler for partially coherent detection.

Double-clad fibers (DCF) have many advantages in fibered confocal microscopes as they allow for coherent illumination through their core and partially coherent detection through their inner cladding. We report a double-clad fiber coupler (DCFC) made from small inner cladding DCF that preserves optical sectioning in confocal microscopy while increasing collection efficiency and reducing coherent effects. Due to the small inner cladding, previously demonstrated fabrication methods could not be translated to this coupler's fabrication.

Laser tissue coagulation and concurrent optical coherence tomography through a double-clad fiber coupler.

Double-clad fiber (DCF) is herein used in conjunction with a double-clad fiber coupler (DCFC) to enable simultaneous and co-registered optical coherence tomography (OCT) and laser tissue coagulation. The DCF allows a single channel fiber-optic probe to be shared: i.e.

Surface plasmon resonance sensor interrogation with a double-clad fiber coupler and cladding modes excited by a tilted fiber Bragg grating.

We present a novel optical fiber surface plasmon resonance (SPR) sensor scheme using reflected guided cladding modes captured by a double-clad fiber coupler and excited in a gold-coated fiber with a tilted Bragg grating. This new interrogation approach, based on the reflection spectrum, provides an improvement in the operating range of the device over previous techniques. The device allows detection of SPR in the reflected guided cladding modes and also in the transmitted spectrum, allowing comparison with standard techniques.

Asymmetric double-clad fiber couplers for endoscopy.

We present an asymmetric double-clad fiber coupler (A-DCFC) exploiting a disparity in fiber etendues to exceed the equipartition limit (≤50% extraction of inner cladding multi-mode light). The A-DCFC is fabricated using two commercially available fibers and a custom fusion-tapering setup to achieve >70% extraction of multi-mode inner cladding light without affecting (>95% transmission) single-mode light propagation in the core. Imaging with the A-DCFC is demonstrated in a spectrally encoded imaging setup using a weakly backscattering biological sample.

Capturing reflected cladding modes from a fiber Bragg grating with a double-clad fiber coupler.

We present a novel measurement scheme using a double-clad fiber coupler (DCFC) and a fiber Bragg grating (FBG) to resolve cladding modes. Direct measurement of the optical spectra and power in the cladding modes is obtained through the use of a specially designed DCFC spliced to a highly reflective FBG written into slightly etched standard photosensitive single mode fiber to match the inner cladding diameter of the DCFC. The DCFC is made by tapering and fusing two double-clad fibers (DCF) together.

Dual-modality needle probe for combined fluorescence imaging and three-dimensional optical coherence tomography.

To the best of our knowledge, we present the first needle probe for combined optical coherence tomography (OCT), and fluorescence imaging. The probe uses double-clad fiber (DCF) that guides the OCT signal and fluorescence excitation light in the core and collects and guides the returning fluorescence in the large-diameter multimode inner cladding. It is interfaced to a 1310 nm swept-source OCT system that has been modified to enable simultaneous 488 nm fluorescence excitation and >500 nm emission detection by using a DCF coupler to extract the returning fluorescence signal in the inner cladding with high efficiency.