1. Articles in category: Gastroenterology

    1-24 of 494 1 2 3 4 ... 19 20 21 »
    1. Optical coherence tomography (OCT) prior to peroral endoscopic myotomy (POEM) reduces procedural time and bleeding: a multicenter international collaborative study

      Optical coherence tomography (OCT) prior to peroral endoscopic myotomy (POEM) reduces procedural time and bleeding: a multicenter international collaborative study

      Background Per-oral endoscopic myotomy (POEM) has emerged as an endoscopic treatment of achalasia. There are no pre-procedural imaging modalities to predict the safest and the most efficacious approach. Aim To evaluate the use of optimal coherence tomography (OCT) in providing a pre-procedural esophageal assessment. Methods Patients undergoing POEM from July 2013 to November 2015 were captured in a multicenter, international registry. Patients who underwent OCT pre-POEM (“OCT arm”) were compared to patients without pre-POEM OCT (“control arm”). OCT images were assessed for the degree of vascularity and the thickness of the circular muscular layer, and an approach was determined. Results ...

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    2. Optical coherence tomography imaging of colonic crypts in a mouse model of colorectal cancer

      Optical coherence tomography imaging of colonic crypts in a mouse model of colorectal cancer

      Aberrant crypt foci (ACF) are abnormal epithelial lesions that precede development of colonic polyps. As the earliest morphological change in the development of colorectal cancer, ACF is a highly studied phenomenon. The most common method of imaging ACF is chromoendoscopy using methylene blue as a contrast agent. Narrow- band imaging is a contrast-agent-free modality for imaging the colonic crypts. Optical coherence tomography (OCT) is an attractive alternative to chromoendoscopy and narrow-band imaging because it can resolve the crypt structure at sufficiently high sampling while simultaneously providing depth-resolved data. We imaged in vivo the distal 15 mm of colon in the ...

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    3. In vivo endoscopic Doppler optical coherence tomography imaging of mouse colon

      In vivo endoscopic Doppler optical coherence tomography imaging of mouse colon

      Colorectal cancer remains the second deadliest cancer in the United States, despite the high sensitivity and specificity of colonoscopy and sigmoidoscopy. While these standard imaging procedures can accurately detect medium and large polyps, some studies have shown miss rates up to 25% for polyps less than 5 mm in diameter. An imaging modality capable of detecting small lesions could potentially improve patient outcomes. Optical coherence tomography (OCT) has been shown to be a powerful imaging modality for adenoma detection in a mouse model of colorectal cancer. While previous work has focused on analyzing the structural OCT images based on thickening ...

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    4. Confocal Laser Endomicroscopy and Optical Coherence Tomography for Diagnosing ILD

      Confocal Laser Endomicroscopy and Optical Coherence Tomography for Diagnosing ILD

      Often, assessing a classifying diagnosis in patients with interstitial lung disease provides a diagnostic challenge. Currently HRCT, endoscopic or surgical video assisted thoracoscopic surgery (VATS) assessment including lung biopsies are diagnostic tools for patients with suspected ILD. However, tissue acquisition is associated with morbidity in these patients with an already compromised pulmonary function. In clinical practice this results in the fact that only a minor part of patients with an indication for tissue acquisition are actually undergoing biopsies. The aim of this study is to determine ILD-characteristics on imagign collected with minimal invasive novel optical techniques, to examine whether the ...

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    5. Tethered capsule detects GI tract disease

      Tethered capsule detects GI tract disease

      The diagnosis and subsequent treatment of many diseases of the upper gastrointestinal tract often call for endoscopic examination. Unfortunately, this is typically expensive, uncomfortable, requires patient sedation and only provides limited information on surface tissues. Subsequent biopsies can provide additional information, but only from limited sample sites. This can be especially problematic when attempting to diagnose diseases with patchy presentations, such as Barrett's oesophagus – in which oesophageal tissues change to resemble those that line the intestine.

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    6. Advances in upper gastrointestinal endoscopy

      Advances in upper gastrointestinal endoscopy

      The rapidly moving technological advances in gastrointestinal endoscopy have enhanced an endoscopist’s ability to diagnose and treat lesions within the gastrointestinal tract. The improvement in image quality created by the advent of high-definition and magnification endoscopy, alongside image enhancement, produces images of superb quality and detail that empower the endoscopist to identify important lesions that have previously been undetectable. Additionally, we are now seeing technologies emerge, such as optical coherence tomography and confocal laser endomicroscopy, that allow the endoscopist to visualize individual cells on a microscopic level and provide a real time, in vivo histological assessment. Within this article ...

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    7. Imaging colon cancer development in mice: IL-6 deficiency prevents adenoma in azoxymethane-treated Smad3 knockouts

      Imaging colon cancer development in mice: IL-6 deficiency prevents adenoma in azoxymethane-treated Smad3 knockouts

      The development of colorectal cancer in the azoxymethane-induced mouse model can be observed by using a miniaturized optical coherence tomography (OCT) imaging system. This system is uniquely capable of tracking disease development over time, allowing for the monitoring of morphological changes in the distal colon due to tumor development and the presence of lymphoid aggregates. By using genetically engineered mouse models deficient in Interleukin 6 (IL-6) and Smad family member 3 (Smad3), the role of inflammation on tumor development and the immune system can be elucidated. Smad3 knockout mice develop inflammatory response, wasting, and colitis associated cancer while deficiency of ...

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    8. Automated segmentation and characterization of esophageal wall in vivo by tethered capsule optical coherence tomography endomicroscopy

      Automated segmentation and characterization of esophageal wall in vivo by tethered capsule optical coherence tomography endomicroscopy

      Optical coherence tomography (OCT) is an optical diagnostic modality that can acquire cross-sectional images of the microscopic structure of the esophagus, including Barrett’s esophagus (BE) and associated dysplasia. We developed a swallowable tethered capsule OCT endomicroscopy (TCE) device that acquires high-resolution images of entire gastrointestinal (GI) tract luminal organs. This device has a potential to become a screening method that identifies patients with an abnormal esophagus that should be further referred for upper endoscopy. Currently, the characterization of the OCT-TCE esophageal wall data set is performed manually, which is time-consuming and inefficient. Additionally, since the capsule optics optimally focus ...

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    9. Optimal operational conditions for supercontinuum-based ultrahigh-resolution endoscopic OCT imaging

      Optimal operational conditions for supercontinuum-based ultrahigh-resolution endoscopic OCT imaging

      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 ...

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    10. NinePoint, Under New Leadership, Bags $31M More For Imaging Tech

      NinePoint, Under New Leadership, Bags $31M More For Imaging Tech

      NinePoint Medical looks to have added roughly $31 million in financing to back its medical imaging technology. According to a regulatory filing , the Bedford, MA-based company has raised about $30.7 million in new venture funding and could add about $10 million more to the pot. The filing lists three investors: they appear to be founding backers Third Rock Ventures and Prospect Venture Partners, and relative newcomer Corning (NYSE: GLW ), which began investing in NinePoint when the company raised a $34 million Series B round in March 2014. Members of each of the three firms—Mark Levin (Third Rock), Russell ...

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    11. Rotational distortion correction in endoscopic optical coherence tomography based on speckle decorrelation

      Rotational distortion correction in endoscopic optical coherence tomography based on speckle decorrelation

      We present a new technique for the correction of nonuniform rotation distortion in catheter-based optical coherence tomography (OCT), based on the statistics of speckle between A-lines using intensity-based dynamic light scattering. This technique does not rely on tissue features and can be performed on single frames of data, thereby enabling real-time image correction. We demonstrate its suitability in a gastrointestinal (GI) balloon-catheter OCT system, determining the actual rotational speed with high temporal resolution, and present corrected cross-sectional and en face views showing significant enhancement of image quality.

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    12. Feasibility of optical coherence tomography for the evaluation of Barrett's mucosa buried underneath esophageal squamous epithelium

      Feasibility of optical coherence tomography for the evaluation of Barrett's mucosa buried underneath esophageal squamous epithelium

      Objectives The evaluation of Barrett's glands buried underneath esophageal squamous epithelium becomes increasingly important to achieve curative treatments. However, clinically available endoscopies have critical limitations in depicting the subsurface structure, resulting in non-curative treatments. Optical coherence tomography (OCT) can acquire a high-resolution cross-sectional image, equivalent to an ‘optical biopsy’. We aimed to assess the feasibility of the in vivo use of probe-type OCT imaging to evaluate Barrett's mucosa buried underneath esophageal squamous epithelium Methods We conducted a single-center prospective study with 14 consecutive patients with Barrett's adenocarcinoma from 2008 to 2014. The enrolled patients were examined by ...

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    13. Advances in the management of Barrett’s esophagus and early esophageal adenocarcinoma

      Advances in the management of Barrett’s esophagus and early esophageal adenocarcinoma

      The incidence of esophageal adenocarcinoma (EAC) has markedly increased in the United States over the last few decades. Barrett’s esophagus (BE) is the most significant known risk factor for this malignancy. Theoretically, screening and treating early BE should help prevent EAC but the exact incidence of BE and its progression to EAC is not entirely known and cost-effectiveness studies for Barrett’s screening are lacking. Over the last few years, there have been major advances in our understanding of the epidemiology, pathogenesis and endoscopic management of BE. These developments focus on early recognition of advanced histology and endoscopic treatment ...

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    14. The use of optical imaging techniques in the gastrointestinal tract

      The use of optical imaging techniques in the gastrointestinal tract

      With significant advances in the management of gastrointestinal disease there has been a move from diagnosing advanced pathology, to detecting early lesions that are potentially amenable to curative endoscopic treatment. This has required an improvement in diagnostics, with a focus on identifying and characterising subtle mucosal changes. There is great interest in the use of optical technologies to predict histology and enable the formulation of a real-time in vivo diagnosis, a so-called ‘optical biopsy’. The aim of this review is to explore the evidence for the use of the current commercially available imaging techniques in the gastrointestinal tract.

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    15. ACG Clinical Guideline: Diagnosis and Management of Barrett’s Esophagus

      ACG Clinical Guideline: Diagnosis and Management of Barrett’s Esophagus

      Barrett’s esophagus (BE) is among the most common conditions encountered by the gastroenterologist. In this document, the American College of Gastroenterology updates its guidance for the best practices in caring for these patients. These guidelines continue to endorse screening of high-risk patients for BE; however, routine screening is limited to men with reflux symptoms and multiple other risk factors. Acknowledging recent data on the low risk of malignant progression in patients with nondysplastic BE, endoscopic surveillance intervals are attenuated in this population; patients with nondysplastic BE should undergo endoscopic surveillance no more frequently than every 3–5 years. Neither ...

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    16. 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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    17. 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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    18. 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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    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 ...

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    20. 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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    21. 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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    22. 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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    23. 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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    24. 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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