1. Articles in category: Gastroenterology

    1-24 of 439 1 2 3 4 ... 17 18 19 »
    1. In vivo molecular mapping of the tumor microenvironment in an azoxymethane-treated mouse model of colon carcinogenesis

      In vivo molecular mapping of the tumor microenvironment in an azoxymethane-treated mouse model of colon carcinogenesis

      Background and Objective Development of miniaturized imaging systems with molecular probes enables examination of molecular changes leading to initiation and progression of colorectal cancer in an azoxymethane (AOM)-induced mouse model of the disease. Through improved and novel studies of animal disease models, more effective diagnostic and treatment strategies may be developed for clinical translation. We introduce use of a miniaturized multimodal endoscope with lavage-delivered fluorescent probes to examine dynamic microenvironment changes in an AOM-treated mouse model. Study Design/Materials and Methods The endoscope is equipped with optical coherence tomography (OCT) and laser induced fluorescence (LIF) imaging modalities. It is ...

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    2. Simultaneous dual-band optical coherence tomography for endoscopic applications

      Simultaneous dual-band optical coherence tomography for endoscopic applications

      Dual-band optical coherence tomography (OCT) can greatly enhance the imaging contrast with potential applications in functional (spectroscopic) analysis. A new simultaneous dual-band Fourier domain mode-locked swept laser configuration for dual-band OCT is reported. It was based on a custom-designed dual-channel driver to synchronize two different wavelength bands at 1310 and 1550 nm, respectively. Two lasing wavelengths were swept simultaneously from 1260 to 1364.8 nm for the 1310-nm band and from 1500 to 1604 nm for the 1550-nm band at an A-scan rate of 45 kHz. Broadband wavelength-division multiplexing was utilized to couple two wavelength bands into a common catheter ...

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    3. Dual optical modality endoscopic imaging of cancer development in the mouse colon

      Dual optical modality endoscopic imaging of cancer development in the mouse colon

      Background and Objective We utilize a miniature, dual-modality endoscope that combines fluorescence-based surface magnifying chromoendoscopy (SMC) and optical coherence tomography (OCT) to follow the anatomical changes that occur during adenoma development in the mouse colon. Materials and Methods Twenty-five mice were treated with the carcinogen azoxymethane (AOM) to induce tumor development in the distal colon, or were treated with saline as control, and were imaged over six months. OCT detects adenoma number with high sensitivity and specificity and can measure lesion size. In methylene blue-lavaged colons, SMC detects changes in the colonic crypts. SMC images of control mouse colons exhibit ...

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    4. NinePoint Medical Appoints Christopher von Jako, Ph.D., to Chief Executive Officer

      NinePoint Medical Appoints Christopher von Jako, Ph.D., to Chief Executive Officer

      NinePoint Medical, Inc., an emerging leader in the development of medical devices for advanced optical imaging, today announced the appointment of Christopher von Jako, Ph.D., as president and chief executive officer. Dr. von Jako brings to NinePoint Medical more than 20 years of experience in the global medical device industry and has demonstrated success leading and growing the value of organizations with early-stage commercial products. “Chris is a passionate and technology-minded individual who deeply understands the dynamics of today’s medical device field,” said Tom Miller, chairman of NinePoint’s board of directors. “We believe his commercial insights and ...

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    5. Ultrahigh speed endoscopic optical coherence tomography for gastroenterology

      Ultrahigh speed endoscopic optical coherence tomography for gastroenterology

      We describe an ultrahigh speed endoscopic swept source optical coherence tomography (OCT) system for clinical gastroenterology using a vertical-cavity surface-emitting laser (VCSEL) and micromotor imaging catheter. The system had a 600 kHz axial scan rate and 8 µm axial resolution in tissue. Imaging was performed with a 3.2 mm diameter imaging catheter at 400 frames per second with a 12 µm spot size. Three-dimensional OCT (3D-OCT) imaging was performed in patients with a cross section of pathologies undergoing upper and lower endoscopy. The use of distally actuated imaging catheters enabled OCT imaging with more flexibility, such as volumetric imaging ...

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    6. Miniaturized endoscopic probe for optical coherence tomography with a tiny magnet driving device

      Miniaturized endoscopic probe for optical coherence tomography with a tiny magnet driving device

      This paper proposes an endoscopic probe for optical coherence tomography (OCT) applying on side-imaging of internal organs. The probe consists of single-mode fiber, a gradient-index (GRIN) lens, and a mirror of cylindrical wedge shape attaching to a magnetized metal piece by epoxy with a short steel wire. For OCT scanning, we use magnetic field generated by a larger magnet externally to drive the rotation of the magnetized metal. Compare with other probes, our probe design has two distinct advantages: 1) The exit beam will be unobstructed during 360 degree circumference scanning because there are no connecting wires in the scanning ...

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    7. Endoscopic imaging in Barrett's esophagus

      Endoscopic imaging in Barrett's esophagus

      Barrett’s esophagus is the only known precursor that predisposes patients to the development of esophageal adenocarcinoma. The current recommended surveillance method is targeted biopsies of any abnormalities followed by random four-quadrant biopsies every 2 cm using standard white light endoscopy. Compliance with this and sampling error are two of the biggest problems. Several novel imaging technologies have been developed to aid the diagnosis of early neoplasia in Barrett’s esophagus. There are emerging data that some of these new modalities can increase the yield of detecting dysplasia. This review will discuss some of the present available techniques and technologies ...

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    8. Endoscopic Eradication Therapy for Barrett's Esophagus

      Endoscopic Eradication Therapy for Barrett's Esophagus

      B arrett’s esophagus (BE) is the precursor lesion to esophageal adenocarcinoma, which in an invasive stage causes significant morbidity and mortality. Surgery was the mainstay of treatment for patients with high-grade dysplasia (HGD) and adenocarcinoma associated with BE. However, surgery in itself carries substantial morbidity. There has been tremendous progress in the minimally invasive treatment of BE in the past decade. The premise to be aggressive in treating dysplastic BE and early-stage adenocarcinoma is to prevent progression to an advanced-stage cancer. Most interventional endoscopists are comfortable treating dysplasia and intramucosal esophageal cancer, although recently there have been emerging data ...

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    9. Advanced Colonoscopic Imaging: Do New Technologies Improve Adenoma Detection?

      Advanced Colonoscopic Imaging: Do New Technologies Improve Adenoma Detection?

      C olorectal cancer (CRC) is the second leading cause of cancer-related mortality in the Western world. 1 Screening colonoscopy and polypectomy have become widely accepted as the most effective available methods for early detection and prevention of CRC and have shown a reduction in mortality in the screened population. 2 However, colonoscopy remains imperfect and several studies have raised concerns about the miss rate of adenomatous polyps during screening. The overall miss rate is approximately 20%, and ranges from 6% for large (10 mm) adenomas to 26% for diminutive (<5 mm) lesions. 3 Missing these adenomas is one of the ...

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    10. Endoscopic optical coherence tomography as a tool to evaluate successful myotomy after a peroral endoscopic myotomy

      Endoscopic optical coherence tomography as a tool to evaluate successful myotomy after a peroral endoscopic myotomy

      Optical coherence tomography (OCT) provides imaging depth down to 3 mm and resolution of 7 μm over a 6-cm length over a 90 second scan. It is used to analyze tissue microstructure to scan for any potential abnormalities in the esophagus. As of now, the utility of OCT in assessing the esophageal muscular layers in achalasia patients after a peroral endoscopic myotomy (POEM) procedure has not been assessed. We present a case in which this device was used for this indication.

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    11. Endoscopy for diagnosis and treatment in esophageal cancers: high-technology assessment

      Endoscopy for diagnosis and treatment in esophageal cancers: high-technology assessment

      The following, from the 12th OESO World Conference: Cancers of the Esophagus, includes commentaries on the endoscopic tools to recognize squamous cell dysplasia; confocal laser endomicroscopy for Barrett's esophagus; confocal microscopy in the cancer patient; optical coherence tomography in the assessment of subsquamous Barrett's metaplasia; endoscopic mucosal resection for high-grade dysplasia in Barrett's esophagus; HALO in the treatment of squamous dysplasia; and the use of fluorescence in situ hybridization to detect dysplasia and adenocarcinoma in patients with Barrett's esophagus.

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    12. A feasibility study of full-field optical coherence tomography for rapid evaluation of EUS-guided microbiopsy specimens

      A feasibility study of full-field optical coherence tomography for rapid evaluation of EUS-guided microbiopsy specimens

      Background Rapid on-site evaluation of cytologic specimens is a way of determining the adequacy of fine-needle aspiration (FNA). However, alternatives may be useful when the presence of a cytotechnologist and/or pathologist is not possible. Objective To evaluate the feasibility of using full-field optical coherence tomography (FFOCT) for FNA specimen quality assessment. Design FFOCT images were acquired on gastric, pancreatic, pelvic, and lymph-node formalin-fixed FNA specimens and were compared with histology of the same samples. Setting Pathology suite in a hospital. Patients Fourteen patients undergoing gastric, pancreatic, pelvic, or lymph-node EUS-guided FNA biopsy. Interventions FFOCT imaging on formalin-fixed samples before ...

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    13. Noninvasive Esophageal Cancer Imaging 2014 R&D 100 Winner

      Noninvasive Esophageal Cancer Imaging 2014 R&D 100 Winner

      2014 R&D 100 Winner There are two forms of esophageal cancer: squamous cell carcinoma and adenocarcinoma. Adenocarcinoma is increasing at a rate greater than all other cancers in the U.S. In fact, the American Cancer Society estimated that in 2013, nearly 18,000 new cases of esophageal cancer cases will be diagnosed and more than 15,000 people will die from the condition. Currently, imaging and screening practices of esophageal tissue are time consuming and costly with questionable effectiveness. For the patient, this process is also invasive. However, NinePoint Medical and Farm Design have developed a solution, the ...

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    14. Optical biopsy approaches in Barrett’s esophagus with next-generation optical coherence tomography

      Optical biopsy approaches in Barrett’s esophagus with next-generation optical coherence tomography

      During endoscopic surveillance and treatment in Barrett’s esophagus, the endoscopist may use a combination of tools to assist in targeting biopsies and endoscopic resections in order to diagnose and treat Barrett’s esophagus–associated neoplasia. There is a concern for subepithelial metaplasia or neoplasia in both naïve and previously treated Barrett’s esophagus. Tools to characterize so-called buried disease may allow for improved detection of occult disease. Optical biopsy with volumetric laser endomicroscopy, or VLE, is based on optical coherence tomography.

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    15. Strategies for the prevention of oesophageal adenocarcinoma

      Strategies for the prevention of oesophageal adenocarcinoma

      The incidence of oesophageal adenocarcinoma has increased by 500% over the past 30 years [1] . Improved understanding of the mechanisms of neoplastic progression provides an opportunity to reverse this trend. A thorough review of emerging strategies aiming to prevent the formation of oesophageal malignancy is presented. These include dietary modification, chemoprevention, early endoscopic identification and treatment of premalignant disease, and the potential for a non-endoscopic screening test. Oesophageal adenocarcinoma has become a major public health problem in the West and it is essential that clinicians are fully informed of risk reduction strategies so that they can be actively promoted in ...

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    16. MIT Receives NIH Grant for Optical Biopsy Using Optical Coherence Tomography

      MIT Receives NIH Grant for Optical Biopsy Using Optical Coherence Tomography

      Massachusetts Institute of Technology Received a 2014 NIH Grant for $302,576 for Optical Biopsy Using Optical Coherence Tomography. THe principal investigator is James Fujimoto. The program began in 1997 and ends in 2019. Below is a summary of the proposed work. This is a multidisciplinary collaboration between investigators at the Massachusetts Institute of Technology and the VA Boston Healthcare System integrating imaging technology research, clinical imaging studies, medical device development and animal imaging studies. Esophageal cancer is a lethal malignancy, with a five-year survival rate of 16%. Barrett's esophagus (BE) and dysplasia are precursors to esophageal adenocarcinoma (EAC ...

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    17. Forward viewing OCT endomicroscopy (Thesis)

      Forward viewing OCT endomicroscopy (Thesis)

      A forward viewing fiber optic-based imaging probe device was designed and constructed for use with ultrahigh speed optical coherence tomography in the human gastrointestinal tract. The light source was a MEMS-VCSEL at 1300 nm wavelength running at 300 kHz sweep rate, giving an effective A-line rate of 600 kHz. Data was acquired with a 1.8 GS/s A/D card optically clocked by a maximum fringe frequency of 1 GHz. The optical beam from the probe was scanned by a freely deflecting optical fiber that was mounted proximally on a piezoelectric tubular actuator, which was electrically driven in two ...

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    18. Effect of differently sized nanoparticles' accumulation on the optical properties of ex vivo normal and adenomatous human colon tissue with OCT imaging and diffuse reflectance spectra

      Effect of differently sized nanoparticles' accumulation on the optical properties of ex vivo normal and adenomatous human colon tissue with OCT imaging and diffuse reflectance spectra

      Using optical coherence tomography (OCT) and diffuse reflectance spectra, we investigated the dynamics of titanium dioxide (TiO 2 ) nanoparticles, of different sizes, when penetrating and accumulating in human normal colon tissue (NC) and adenomatous colon tissue (AC). The process of nanoparticle penetration and accumulation in biotissue is accompanied by changes in the optical properties of tissue. Continuous OCT monitoring showed that, after application of TiO 2 nanoparticles, the OCT signal intensities of NC and ac both increase with time, and the larger nanoparticles tend to produce a greater signal enhancement in the same type of tissue. The average attenuation coefficient ...

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    19. NinePoint Medical Receives 2014 MDEA Silver Medal for NvisionVLE Imaging System

      NinePoint Medical Receives 2014 MDEA Silver Medal for NvisionVLE Imaging System

      NinePoint Medical, Inc., an emerging leader in the development of medical devices for advanced optical imaging, today announced the company was honored with a silver medal at the 2014 Medical Design Excellence Awards (MDEA) for the company’s volumetric optical coherence tomography device, the NvisionVLE Imaging System™. NinePoint and NvisionVLE were among 54 cutting-edge products and companies across 11 medical technology product categories selected as finalists. “Our team has worked diligently over the past four years to bring the NvisionVLE Imaging System to clinicians and patients, and we are pleased that our efforts were recognized by the MDEA with this ...

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    20. Massachusetts General Hospital Receives NIH Grant for Improved Screening and Surveillance in Barrett's Patients

      Massachusetts General Hospital Receives NIH Grant for Improved Screening and Surveillance in Barrett's Patients

      Massachusetts General Hospital received a 2014 NIH grant for $464,015 for Improved Screening and Surveillance in Barrett's Patients. The principal investigator is Gary Tearney. The program began in 2003 and ends in 2015. Below is a summary of the proposed work. Barrett's esophagus (BE) is a metaplastic condition that is associated with chronic gastroesophageal reflux disease (GERD). BE is important because it can progress to esophageal adenocarcinoma, a cancer with a high mortality rate and a rapidly rising incidence. Since identification of BE with dysplasia or early cancer can lead to cure, gastroenterological societies recommend that patients ...

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    21. Gradient index lens based combined two-photon microscopy and optical coherence tomography

      Gradient index lens based combined two-photon microscopy and optical coherence tomography

      We report a miniaturized probe-based combined two-photon microscopy (TPM) and optical coherence tomography (OCT) system. This system is to study the colorectal cancer in mouse models by visualizing both cellular and structural information of the colon in 3D with TPM and OCT respectively. The probe consisted of gradient index (GRIN) lenses and a 90° reflecting prism at its distal end for side-viewing, and it was added onto an objective lens-based TPM and OCT system. The probe was 2.2 mm in diameter and 60 mm in length. TPM imaging was performed by raster scanning of the excitation focus at the ...

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    22. Quantitative Diagnosis of Colorectal Polyps by Spectral Domain Optical Coherence Tomography

      Quantitative Diagnosis of Colorectal Polyps by Spectral Domain Optical Coherence Tomography

      The principal aim of this study is to investigate the scattering coefficient of colorectal polyp tissues using an optical coherence tomography (OCT) technique. It combines the existing scattering coefficient model and spectral domain OCT to achieve method of early diagnosis of colorectal polyp in hospitals. Seventeen patients were studied, and a total of 1456 data points were extracted by curve-fitting the OCT signals into a confocal single-backscattering model. The results show that the mean scattering coefficient value for colorectal polyps is 1.91 mm −1 (std: ±0.54 mm −1 ), which is between the values for normal and malignant tissues ...

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    23. Endoscopic Optical Coherence Tomography for Clinical Gastroenterology

      Endoscopic Optical Coherence Tomography for Clinical Gastroenterology

      Optical coherence tomography (OCT) is a real-time optical imaging technique that is similar in principle to ultrasonography, but employs light instead of sound waves and allows depth-resolved images with near-microscopic resolution. Endoscopic OCT allows the evaluation of broad-field and subsurface areas and can be used ancillary to standard endoscopy, narrow band imaging, chromoendoscopy, magnification endoscopy, and confocal endomicroscopy. This review article will provide an overview of the clinical utility of endoscopic OCT in the gastrointestinal tract and of recent achievements using state-of-the-art endoscopic 3D-OCT imaging systems.

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    24. New Clinical Data using the NvisionVLE™ Imaging System to be presented at Digestive Disease Week® 2014

      New Clinical Data using the NvisionVLE™ Imaging System to be presented at Digestive Disease Week® 2014

      NinePoint Medical, Inc. , an emerging leader in the development of medical devices for advanced optical imaging, today announced that new clinical data, by various investigators using its proprietary NvisionVLE ™ Imaging System, will be presented in a series of 13 oral, video and poster presentations during Digestive Disease Week ® (DDW ® ) 2014. The annual meeting will take place May 3-6 at McCormick Place in Chicago. The schedule for scientific presentations related to advanced optical coherence tomography (OCT) and the NvisionVLE Imaging System at DDW 2014 is provided below. The NvisionVLE Imaging System is indicated for use as an imaging tool in the ...

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    1-24 of 439 1 2 3 4 ... 17 18 19 »
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