1. Articles in category: Gastroenterology

    49-72 of 527 « 1 2 3 4 5 6 ... 20 21 22 »
    1. Online Tracking and Retargeting with Applications to Optical Biopsy in Gastrointestinal Endoscopic Examinations

      Online Tracking and Retargeting with Applications to Optical Biopsy in Gastrointestinal Endoscopic Examinations

      With recent advances in biophotonics, techniques such as narrow band imaging, confocal laser endomicroscopy, fluorescence spectroscopy, and optical coherence tomography, can be combined with normal white-light endoscopes to provide in vivo microscopic tissue characterisation, potentially avoiding the need for offline histological analysis. Despite the advantages of these techniques to provide online optical biopsy in situ , it is challenging for gastroenterologists to retarget the optical biopsy sites during endoscopic examinations. This is because optical biopsy does not leave any mark on the tissue. Furthermore, typical endoscopic cameras only have a limited field-of-view and the biopsy sites often enter or exit the ...

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    2. Monitoring disposition of tethered capsule endoscope in esophagus

      Monitoring disposition of tethered capsule endoscope in esophagus

      A scanning flexible endoscope includes a tether attached to a capsule. The tether controls a disposition of the capsule within a body lumen such as the esophagus. A scanning device in the capsule optically scans the adjacent tissue on the inside surface of the body lumen as the capsule is moved axially through the body lumen. A non-contact sensor responds to indicia on the tether to measure a relative position of the tether and the capsule in the body lumen. The indicia can be analog or digital in form and the sensor can be either magnetic, or optical. A wiper ...

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    3. Advanced Imaging in Barrett’s Esophagus

      Advanced Imaging in Barrett’s Esophagus

      Enhanced imaging technologies such as narrow band imaging, flexible spectral imaging color enhancement, i-Scan, confocal laser endomicroscopy, and optical coherence tomography are readily available for use by endoscopists in routine clinical practice. In November 2014, the American Gastroenterological Association’s Center for GI Innovation and Technology conducted a 2-day workshop to discuss endoscopic image enhancement technologies, focusing on their role in 2 specific clinical conditions (colon polyps and Barrett’s esophagus) and on issues relating to training and implementation of these technologies (white papers). Although the majority of the studies that use enhanced imaging technologies have been positive, these techniques ...

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    4. Emerging optical methods for surveillance of Barrett's oesophagus

      Emerging optical methods for surveillance of Barrett's oesophagus

      The rapid rise in incidence of oesophageal adenocarcinoma has motivated the need for improved methods for surveillance of Barrett's oesophagus. Early neoplasia is flat in morphology and patchy in distribution and is difficult to detect with conventional white light endoscopy (WLE). Light offers numerous advantages for rapidly visualising the oesophagus, and advanced optical methods are being developed for wide-field and cross-sectional imaging to guide tissue biopsy and stage early neoplasia, respectively. We review key features of these promising methods and address their potential to improve detection of Barrett's neoplasia. The clinical performance of key advanced imaging technologies is ...

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    5. In vivo molecular imaging of colorectal cancer using quantum dots targeted to vascular endothelial growth factor receptor 2 and optical coherence tomography/laser-induced fluorescence dual-modality imaging

      In vivo molecular imaging of colorectal cancer using quantum dots targeted to vascular endothelial growth factor receptor 2 and optical coherence tomography/laser-induced fluorescence dual-modality imaging

      Optical coherence tomography/laser induced fluorescence (OCT/LIF) dual-modality imaging allows for minimally invasive, nondestructive endoscopic visualization of colorectal cancer in mice. This technology enables simultaneous longitudinal tracking of morphological (OCT) and biochemical (fluorescence) changes as colorectal cancer develops, compared to current methods of colorectal cancer screening in humans that rely on morphological changes alone. We have shown that QDot655 targeted to vascular endothelial growth factor receptor 2 (QD655-VEGFR2) can be applied to the colon of carcinogen-treated mice and provides significantly increased contrast between the diseased and undiseased tissue with high sensitivity and specificity ex vivo . QD655-VEGFR2 was used in ...

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    6. Comparative Diagnostic Performance of Volumetric Laser Endomicroscopy and Confocal Laser Endomicroscopy in the Detection of Dysplasia Associated with Barrett’s Esophagus

      Comparative Diagnostic Performance of Volumetric Laser Endomicroscopy and Confocal Laser Endomicroscopy in the Detection of Dysplasia Associated with Barrett’s Esophagus

      Background & Aims Probe-based confocal laser endomicroscopy (pCLE) and volumetric laser endomicroscopy (VLE) are advanced endoscopic imaging modalities that may be useful in the diagnosis of dysplasia associated with Barrett’s esophagus (BE). We performed pCLE examination in ex-vivo endoscopic mucosal resection (EMR) specimens and compared the diagnostic performance of using the current VLE scoring index (OCT-SI) and a novel VLE diagnostic algorithm (VLE-DA) for the detection of dysplasia. Methods 27 patients with BE enrolled in a surveillance program at a tertiary center underwent 50 clinically indicated EMRs that were imaged with VLE and pCLE and classified into neoplastic (N=34 ...

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    7. Beyond Endoscopy-Ultrasound, Optical Coherence Tomography and Confocal Laser Endomicroscopy (Book Chapter)

      Beyond Endoscopy-Ultrasound, Optical Coherence Tomography and Confocal Laser Endomicroscopy (Book Chapter)

      One of the main challenges in endoscopic diagnosis and treatment of upper urinary tract urothelial carcinoma is the complicated anatomy and the small size of the upper urinary tract, resulting in high demands on the armamentarium and expertise of the urologist. Difficulties to reach the complete collecting system could result in an incomplete visual inspection.

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    8. Miniature endoscopic optical coherence tomography for calculus detection

      Miniature endoscopic optical coherence tomography for calculus detection

      The effective treatment of periodontitis involves the detection and removal of subgingival dental calculus. However, subgingival calculus is more difficult to detect than supragingival calculus because it is firmly attached to root surfaces within periodontal pockets. To achieve a smooth root surface, clinicians often remove excessive amounts of root structure because of decreased visibility. In addition, enamel pearl, a rare type of ectopic enamel formation on the root surface, can easily be confused with dental calculus in the subgingival environment. In this study, we developed a fiber-probe swept-source optical coherence tomography (SSOCT) technique and combined it with the quantitative measurement ...

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    9. Recent development of optical coherence tomography for preoperative diagnosis of esophageal malignancies

      Recent development of optical coherence tomography for preoperative diagnosis of esophageal malignancies

      Endoscopic diagnosis with histological evidence is necessary to decide the best strategy for treating esophageal squamous cell carcinoma and Barrett’s-associated neoplasia, and the recent development of endoscopic technologies have made possible real-time information of malignant hallmarks. We focused on the development of optical coherence tomography (OCT), the only technology that can depict real-time cross-sectional images with high resolution. With the improvements in image resolution, acquisition rate and demonstrable area of three-dimensional devices with Doppler capability, OCT imaging was shown to enable visualization of structural/ functional alterations in the mucosal/submucosal tissue of the esophagus, resulting in more accurate preoperative ...

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    10. Finding a needle in a haystack: use of volumetric laser endomicroscopy in targeting focal dysplasia in long-segment Barrett’s esophagus

      Finding a needle in a haystack: use of volumetric laser endomicroscopy in targeting focal dysplasia in long-segment Barrett’s esophagus

      A 64-year-old man underwent esophagoscopy 15 months earlier, which diagnosed long-segment Barrett’s esophagus. Examination of random biopsy specimens yielded a diagnosis of intestinal metaplasia, with 1 biopsy specimen as indefinite for dysplasia. Two subsequent esophagoscopies were performed 6 months apart, and random biopsy specimens were negative for dysplasia. The patient was referred for volumetric laser endomicroscopy (VLE) (NVisionVLE, NinePoint Medical, Cambridge, Mass). At esophagoscopy, high-definition white-light endoscopy showed a 7-cm segment of flat salmon-colored mucosa (Prague class C6M7) ( A ).

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    11. Detection of buried Barrett’s glands after radiofrequency ablation with volumetric laser endomicroscopy

      Detection of buried Barrett’s glands after radiofrequency ablation with volumetric laser endomicroscopy

      Background and Aims The prevalence and clinical relevance of buried Barrett’s glands (BB) after radiofrequency ablation (RFA) in Barrett’s esophagus (BE) are debated. Recent optical coherence tomography studies demonstrated a high prevalence of BBs. Direct histological correlation, however, has been lacking. Volumetric laser endomicroscopy (VLE) is a second-generation optical coherence tomography system capable of scanning a large surface of the esophageal wall layers with low-power microscopy resolution. The aim was to evaluate whether post-RFA subsquamous glandular structures (SGSs), detected with VLE, actually correspond to BBs by pursuing direct histological correlation with VLE images. Methods In vivo VLE was ...

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    12. Barrett's Esophagus: Advanced Imaging Options For Early Cancer Detection

      Barrett's Esophagus: Advanced Imaging Options For Early Cancer Detection

      This Video describes the basic approach to endoscopic inspection of Barrett's esophagus. It Focuses on new imaging technologies that increase our ability to detect precancerous or cancerous changes and thus allow us to better target treatment to these areas. For more information on Barrett's Esophagus, visit: http://www.mayoclinic.org/diseases-co...

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    13. MGH Receives NIH Grant To Study Natural History of Barrett's Esophagus Using Capsule Endomicroscopy

      MGH Receives NIH Grant To Study Natural History of Barrett's Esophagus Using Capsule Endomicroscopy

      Massachusetts General Hospital Receives a 2015 NIH Grant for $472,417 To Study Natural History of Barrett's Esophagus Using Capsule Endomicroscopy. The program began in 2014 and ends in 2019. Below is a summary of the proposed work. Barrett's esophagus (BE) is a condition where normal esophageal squamous mucosa changes to metaplastic columnar mucosa in response to chronic acid reflux. BE can progress to esophageal adenocarcinoma (EAC), a prevalent (~12,000 cases per year) and deadly cancer (~15% 5-year mortality rate). Current BE management strategies of anti-reflux therapy, endoscopic screening, and regular endoscopic biopsy surveillance and ablation therapy ...

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    14. Endoscopic Mucosal Resection and Endoscopic Submucosal Dissection for Endoscopic Therapy of Barrett’s Esophagus-related Neoplasia

      Endoscopic Mucosal Resection and Endoscopic Submucosal Dissection for Endoscopic Therapy of Barrett’s Esophagus-related Neoplasia

      Barrett’s esophagus (BE) is characterized by a change in the lining of the esophagus from stratified squamous epithelium to a metaplastic columnar epithelium (IM) that has a low, but real, malignant potential. The progression of BE to carcinoma occurs in a stepwise fashion from IM through dysplasia (low grade to high grade [HGD]). Endoscopic surveillance is recommended for patients with BE to detect and manage

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    15. Miniaturized magnetic-driven scanning probe for endoscopic optical coherence tomography

      Miniaturized magnetic-driven scanning probe for endoscopic optical coherence tomography

      We designed and implemented a magnetic-driven scanning (MDS) probe for endoscopic optical coherence tomography (OCT). The probe uses an externally-driven tiny magnet in the distal end to achieve unobstructed 360-degree circumferential scanning at the side of the probe. The design simplifies the scanning part inside the probe and thus allows for easy miniaturization and cost reduction. We made a prototype probe with an outer diameter of 1.4 mm and demonstrated its capability by acquiring OCT images of ex vivo trachea and artery samples from a pigeon. We used a spectrometer-based Fourier-domain OCT system and the system sensitivity with our ...

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    16. Micro-Tech Developing a SS-OCT Endoscopic System for Gastroenterology

      Micro-Tech Developing a SS-OCT Endoscopic System for Gastroenterology

      Micro-Tech an medical company in China established in 1999 is developing a SS-OCT endoscopic system. The system was shown at DDW 2015 and was developed by Jiefeng Xi a Principle Engineer at Micro-Tech and former PhD student at Johns Hopkins who graduated in July 2014. For more information click HERE .

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    17. Optical coherence tomography after POEM

      Optical coherence tomography after POEM

      Amy Tyberg, MD, from Weill Cornell Medical College in New York, New York, USA presents this video case “Endoscopic optical coherence tomography as a tool to evaluate successful myotomy after a peroral endoscopic myotomy.” This case describes a 51-year-old woman with achalasia who underwent a per-oral endoscopic myotomy (POEM) with complete resolution of her symptoms post-procedure. A repeat endoscopy with optical coherence tomography (OCT) was performed post-procedure to confirm successful myotomy.  

      OCT is an exciting new technology that allows for two-dimensional, cross-sectional imaging of the esophageal wall in vivo. This technology has been well studied in Barrett’s esophagus  as ...

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    18. Optical coherence tomography and intravascular ultrasound evaluation of cardiac allograft vasculopathy with and without intimal neovascularization

      Optical coherence tomography and intravascular ultrasound evaluation of cardiac allograft vasculopathy with and without intimal neovascularization

      Aims Neovascularization is closely associated with plaque progression in non-heart transplantation subjects; on the other hand, cardiac allograft vasculopathy causes unfavourable outcomes. Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) can provide microscopic assessment in vivo . The aim of this study was to investigate the impact of neovascularization on intimal proliferation. Methods and results Both IVUS and OCT were attempted in 45 consecutive patients during annual catheterization after heart transplantation. There were 115 vessels [28 vessels were catheterized within 8 weeks of heart transplantation (baseline)]. IVUS analysis assessed vessel, luminal, and intimal (vessel-lumen) volume using Simpson's method. Qualitative parameters ...

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    19. Emerging optical methods for surveillance of Barrett's oesophagus

      Emerging optical methods for surveillance of Barrett's oesophagus

      The rapid rise in incidence of oesophageal adenocarcinoma has motivated the need for improved methods for surveillance of Barrett's oesophagus. Early neoplasia is flat in morphology and patchy in distribution and is difficult to detect with conventional white light endoscopy (WLE). Light offers numerous advantages for rapidly visualising the oesophagus, and advanced optical methods are being developed for wide-field and cross-sectional imaging to guide tissue biopsy and stage early neoplasia, respectively. We review key features of these promising methods and address their potential to improve detection of Barrett's neoplasia. The clinical performance of key advanced imaging technologies is ...

      Read Full Article
    20. New Clinical Data Using the NvisionVLE® Imaging System to be Presented at Digestive Disease Week® 2015

      New Clinical Data Using the NvisionVLE® Imaging System to be Presented at Digestive Disease Week® 2015

      NinePoint Medical, Inc. , an emerging leader in the development of medical devices for advanced imaging, today announced that new clinical data relating to its proprietary NvisionVLE ® Imaging System, will be presented in a series of oral and poster presentations during Digestive Disease Week ® (DDW ® ) 2015. The annual meeting will take place May 16-19th in Washington, DC. The schedule for scientific presentations related to advanced optical coherence tomography (OCT) and the NvisionVLE ® Imaging System at DDW 2015 is provided below. SATURDAY, May 16, 2015 Three posters will be presented on Saturday, May 16 at 9:30am in Hall C of Walter ...

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    21. Safety and feasibility of volumetric laser endomicroscopy in patients with Barrett’s esophagus (with videos)

      Safety and feasibility of volumetric laser endomicroscopy in patients with Barrett’s esophagus (with videos)

      Background Volumetric laser endomicroscopy (VLE) produces high-resolution, cross-sectional surface, and subsurface images for detecting neoplasia, targeting biopsies, and guiding real-time treatment. Objective To evaluate the safety and feasibility of the Nvision VLE system. Design Prospective, multicenter study. Setting Tertiary-care medical centers. Patients One hundred patients with suspected Barrett’s esophagus, including 52 patients with prior endotherapy. Interventions The first-generation Nvision VLE Imaging System, a balloon-centered, rotating optical probe provided images of the mucosa and submucosa through a 6-cm segment length and 360° scan of the distal esophagus. Main Outcome Measurements Acquisition of a complete, 6-cm scan from the distal esophagus ...

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    22. Volumetric laser endomicroscopy in Barrett's esophagus: a feasibility study on histological correlation

      Volumetric laser endomicroscopy in Barrett's esophagus: a feasibility study on histological correlation

      Volumetric laser endomicroscopy (VLE) is a novel balloon-based optical coherence tomography (OCT) imaging technique that may improve detection of early neoplasia in Barrett's esophagus (BE). Most OCT studies lack a direct correlation between histology and OCT images. The aim is to investigate the optimal approach for achieving one-to-one correlation of ex-vivo VLE images of endoscopic resection (ER) specimens with histology. BE patients with and without early neoplasia underwent ER after delineating areas with electrocoagulation markers (ECM). After ER, specimens underwent additional ex-vivo marking with several different markers (ink, pin, Gold Probe) followed by ex-vivo VLE scanning. ER specimens were ...

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    23. Feature Of The Week 5/10/2015: Laser Tissue Coagulation and Concurrent Optical Coherence Tomography Through a Double-Clad Fiber Coupler

      Feature Of The Week 5/10/2015: Laser Tissue Coagulation and Concurrent Optical Coherence Tomography Through a Double-Clad Fiber Coupler

      This work is the result of a collaboration between researchers from Professor Caroline Boudoux’s team from Polytechnique Montréal (Canada) and Professor Brett E. Bouma’s team at the Wellman Center for Photomedicine (MGH, Boston). The goal is to assess whether OCT-guided biopsy could benefit from the use of double-clad fiber (DCF). DCF allows a single channel fiber-optic probe to be shared: i.e. the core propagating the OCT signal while the inner cladding delivers the coagulation laser light used for laser marking. DCF is herein used in conjunction with a double-clad fiber coupler (DCFC) to enable simultaneous and ...

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    24. Ultra-thin and flexible endoscopy probe for optical coherence tomography based on stepwise transitional core fiber

      Ultra-thin and flexible endoscopy probe for optical coherence tomography based on stepwise transitional core fiber

      We present an ultra-thin fiber-body endoscopy probe for optical coherence tomography (OCT) which is based on a stepwise transitional core (STC) fiber. In a minimalistic design, our probe was made of spliced specialty fibers that could be directly used for beam probing optics without using a lens. In our probe, the OCT light delivered through a single-mode fiber was efficiently expanded to a large mode field of 24 μm diameter for a low beam divergence. The size of our probe was 85 μm in the probe’s diameter while operated in a 160-μm thick protective tubing. Through theoretical and ...

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    49-72 of 527 « 1 2 3 4 5 6 ... 20 21 22 »
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