1. Articles in category: Gastroenterology

    1-24 of 649 1 2 3 4 ... 25 26 27 »
    1. Epidemiology, Diagnosis, Staging and Multimodal Therapy of Esophageal and Gastric Tumors

      Epidemiology, Diagnosis, Staging and Multimodal Therapy of Esophageal and Gastric Tumors

      Gastric and esophageal tumors are diverse neoplasms that involve mucosal and submucosal tissue layers and include squamous cell carcinomas, adenocarcinomas, spindle cell neoplasms, neuroendocrine tumors, marginal B cell lymphomas, along with less common tumors. The worldwide burden of esophageal and gastric malignancies is significant, with esophageal and gastric cancer representing the ninth and fifth most common cancers, respectively. The approach to diagnosis and staging of these lesions is multimodal and includes a combination of gastrointestinal endoscopy, endoscopic ultrasound, and cross-sectional imaging. Likewise, therapy is multidisciplinary and combines therapeutic endoscopy, surgery, radiotherapy, and systemic chemotherapeutic tools. Future directions for diagnosis of ...

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      Mentions: Brown University
    2. Feasibility and safety of tethered capsule endomicroscopy in patients with Barrett’s esophagus in a multi-center study

      Feasibility and safety of tethered capsule endomicroscopy in patients with Barrett’s esophagus in a multi-center study

      Background & Aims Tethered capsule endomicroscopy (TCE) involves swallowing small tethered pill that implements optical coherence tomography (OCT) imaging, procuring high resolution images of the whole esophagus. Here, we demonstrate and evaluate the feasibility and safety of TCE and a portable OCT imaging system in patients with Barrett’s esophagus (BE) in a multi-center (5-site) clinical study. Methods Untreated patients with BE as per endoscopic biopsy diagnosis were eligible to participate in the study. TCE procedures were performed in unsedated patients by either doctors or nurses. After the capsule was swallowed, the device continuously obtained 10-μm-resolution cross-sectional images as it ...

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    3. Tethered capsule provides high-quality images for Barrett’s esophagus

      Tethered capsule provides high-quality images for Barrett’s esophagus

      Researchers were able obtain high-quality images of Barrett’s esophagus using tethered capsule endomicroscopy, according to study results. Guillermo Tearney , MD, PhD, from the Wellman Center for Photomedicine at Massachusetts General Hospital, and colleagues wrote that the capsule, which uses optical coherence tomography, (OCT-TCE) provides 3D microscopic images of the esophagus for BE. “OCT-TCE does not require sedation, obtains microscopic images of the entire esophagus, and is a faster and more convenient procedure,” they wrote. “Our group and others have successfully conducted OCT-TCE in pilot, single-center studies showing exemplary images that demonstrate the potential of this technology to improve upper ...

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    4. Optical coherence tomography for the early detection of colorectal dysplasia and cancer: validation in a murine model

      Optical coherence tomography for the early detection of colorectal dysplasia and cancer: validation in a murine model

      Background: There is an urgent need to develop a non-invasive imaging technique for detecting colorectal dysplasia and cancer. Technology for early and real-time microscopic assessments to select the most representative biopsy sites would also be of clinical value. In this study, we explored the sensitivity of optical coherence tomography (OCT) in detecting local lesions to demonstrate its potential for the early detection of colorectal dysplasia and cancer. Methods: An azoxymethane/dextran sodium sulfate mouse model of colorectal carcinogenesis was utilized. Mice were imaged by OCT, and colorectal tissue sections were observed with hematoxylin and eosin staining. The results of the ...

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      Mentions: Fudan University
    5. Stick-slip nonuniform rotation distortion correction in distal scanning optical coherence tomography catheters

      Stick-slip nonuniform rotation distortion correction in distal scanning optical coherence tomography catheters

      We present a robust and fiducial-marker-free algorithm that can identify and correct stick-slip distortion caused by nonuniform rotation (or beam scanning) in distally scanned catheters for endoscopic optical coherence tomography (OCT) images. This algorithm employs spatial frequency analysis to select and remove distortions. We demonstrate the feasibility of this algorithm on images acquired from ex vivo rat colon with a distally scanned DC motor-based endoscope. The proposed algorithm can be applied to general endoscopic OCT images for correcting nonuniform rotation distortion.

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    6. The Use of a OCT Probe in Assessment of Endoscopic and Surgical Resection Specimen of Gastrointestinal Tract

      The Use of a OCT Probe in Assessment of Endoscopic and Surgical Resection Specimen of Gastrointestinal Tract

      This is a pilot study aiming to investigate the ability of a novel Optical Coherence Tomography (OCT) probe in assessing the different layers of the gastrointestinal tract and the depth of invasion of early neoplasia, utilising surgically and endoscopically resected specimens Endoscopic treatment of early neoplasia in the gastrointestinal tract has been established as the standard therapy in the past decade. Various endoscopic resection techniques have been developed, such as endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD), to ensure complete removal of such lesions and avoid recurrence. Successful endoscopic resection of early gastrointestinal (GI) neoplasia relies on accurate ...

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    7. Dual-Stage U-Shape Convolutional Network for Esophageal Tissue Segmentation in OCT Images

      Dual-Stage U-Shape Convolutional Network for Esophageal Tissue Segmentation in OCT Images

      Automatic segmentation is the crucial step for esophageal optical coherence tomography (OCT) image processing, which is able to highlight diagnosis-related tissue layers and provide characteristics such as shape and thickness for esophageal disease diagnosis. This study proposes a dual-stage framework using a specifically designed encoder-decoder network configuration for accurate and reliable esophageal layer segmentation, which is named as the dual-stage U-shape convolutional network (D-UCN). The proposed approach utilized one UCN to locate the target tissue region, which is followed by another UCN with similar architecture to achieve the final segmentation. In this way, the proposed strategy effectively solves the problems ...

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    8. Correction of circumferential and longitudinal motion distortion in high-speed catheter/endoscope-based optical coherence tomography

      Correction of circumferential and longitudinal motion distortion in high-speed catheter/endoscope-based optical coherence tomography

      Catheter/endoscope-based optical coherence tomography (OCT) is a powerful modality that visualizes structural information in luminal organs. Increases in OCT speed have reduced motion artifacts by enabling acquisition faster than or comparable to the time scales of physiological motion. However motion distortion remains a challenge because catheter/endoscope OCT imaging involves both circumferential and longitudinal scanning of tissue. This paper presents a novel image processing method to estimate and correct motion distortion in both the circumferential and longitudinal directions using a single en face image from a volumetric data set. The circumferential motion distortion is estimated and corrected using the ...

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    9. Advanced endoscopic imaging for detecting and guiding therapy of early neoplasias of the esophagus

      Advanced endoscopic imaging for detecting and guiding therapy of early neoplasias of the esophagus

      Esophageal cancers, largely adenocarcinoma in Western countries and squamous cell cancer in Asia, present a significant burden of disease and remain one of the most lethal of cancers. Key to improving survival is the development and adoption of new imaging modalities to identify early neoplastic lesions, which may be small, multifocal, subsurface, and difficult to detect by standard endoscopy. Such advanced imaging is particularly relevant with the emergence of ablative techniques that often require multiple endoscopic sessions and may be complicated by bleeding, pain, strictures, and recurrences. Assessing the specific location, depth of involvement, and features correlated with neoplastic progression ...

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    10. Visualization of Bacterial Colonization and Cellular Layers in a Gut-on-a-Chip System Using Optical Coherence Tomography

      Visualization of Bacterial Colonization and Cellular Layers in a Gut-on-a-Chip System Using Optical Coherence Tomography

      Imaging of cellular layers in a gut-on-a-chip system has been confined to two-dimensional (2D)-imaging through conventional light microscopy and confocal laser scanning microscopy (CLSM) yielding three-dimensional- and 2D-cross-sectional reconstructions. However, CLSM requires staining and is unsuitable for longitudinal visualization. Here, we compare merits of optical coherence tomography (OCT) with those of CLSM and light microscopy for visualization of intestinal epithelial layers during protection by a probiotic Bifidobacterium breve strain and a simultaneous pathogen challenge by an Escherichia coli strain. OCT cross-sectional images yielded film thicknesses that coincided with end-point thicknesses derived from cross-sectional CLSM images. Light microscopy on histological ...

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    11. Endoscopic imaging in inflammatory bowel disease: current developments and emerging strategies

      Endoscopic imaging in inflammatory bowel disease: current developments and emerging strategies

      Developments in enhanced and magnified endoscopy have signified major advances in endoscopic imaging of ileocolonic pathology in inflammatory bowel disease (IBD). Artificial intelligence is increasingly being used to augment the benefits of these advanced techniques. Nevertheless, treatment of IBD patients is frustrated by high rates of non-response to therapy, while delayed detection and failures to detect neoplastic lesions impede successful surveillance. A possible solution is offered by molecular imaging, which adds functional imaging data to mucosal morphology assessment through visualizing biological parameters. Other label-free modalities enable visualization beyond the mucosal surface without the need of tracers.

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    12. Study of Gastrointestinal Dysfunction and Enteric Neural Pathology in Patients With Parkinson's Disease

      Study of Gastrointestinal Dysfunction and Enteric Neural Pathology in Patients With Parkinson's Disease

      The purpose of this study is to establish the esophageal pathology findings as imaged with tethered capsule microscopy in subjects with Parkinson Disease. Images from patients with Parkinson disease will be compared to our previously obtained images in healthy subjects to establish the spectrum of esophageal pathologies occurring in patients with Parkinson disease by OCT imaging. In the case of imaging internal luminal organs, like the esophagus, OCT light is delivered via a long catheter. We have developed a new technique termed Tethered Capsule Endomicroscopy (TCE). TCE involves swallowing a tethered capsule that acquires cross-sectional microscopic images of the entire ...

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    13. Optical Imaging of Gastrointestinal Biopsy Samples and Their Correlation With Histology

      Optical Imaging of Gastrointestinal Biopsy Samples and Their Correlation With Histology

      The investigators have previously developed optical imaging systems that have been able to provide highly detailed images of tissue structures in multiple application areas including Cardiology, Gastroenterology, and Pulmonology. They are looking to continue the advancement of these various technologies under development. The population will include subjects who are undergoing elective esophagogastroduodenoscopy with biopsy, colonoscopy with biopsy, and/or endo-mucosal resection.The endoscopist will take no more than 3 biopsies in addition to the standard of care biopsies. The study will be optical imaging of the ex vivo GI specimens that are being collected. Specimens will be collected for research ...

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    14. Evaluation of Tethered Capsule Endomicroscopy as a Screening Tool for Barrett's Esophagus in the Primary Care Setting

      Evaluation of Tethered Capsule Endomicroscopy as a Screening Tool for Barrett's Esophagus in the Primary Care Setting

      The investigators have developed a tethered capsule OCT device intended as an inexpensive screening tool for BE. The capsule, which is attached to a thin, flexible tether, is reusable after being processed by a standard disinfection technique. Used without sedation, the capsule is swallowed by the participant and travels in the esophagus to the gastroesophageal junction (GEJ) via peristalsis. Cross-sectional microscopic OCT images of the entire esophagus are collected during transit. The total time needed for swallowing, imaging and retrieval does not exceed 10 minutes, with a total of 30 minutes for the procedure. The investigators have tested the feasibility ...

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    15. Tethered capsule en face optical coherence tomography for imaging Barrett’s oesophagus in unsedated patients

      Tethered capsule en face optical coherence tomography for imaging Barrett’s oesophagus in unsedated patients

      Objective Barrett’s oesophagus (BE) screening outside the endoscopy suite can identify patients for surveillance and reduce mortality. Tethered capsule optical coherence tomography (OCT) can volumetrically image oesophageal mucosa in unsedated patients and detect features of BE. We investigated ultrahigh-speed tethered capsule swept-source OCT (SS-OCT), improved device design, developed procedural techniques and measured capsule contact, longitudinal pullback non-uniformity and patient toleration. Design OCT was performed in 16 patients prior to endoscopic surveillance/treatment. Unsedated patients swallowed the capsule with sips of water and the tether was pulled back to image the oesophagus. SS-OCT at 1 000 000 A-scans/s enabled ...

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    16. Comparison of Optical Imaging Techniques to Quantitatively Assess the Perfusion of the Gastric Conduit during Oesophagectomy

      Comparison of Optical Imaging Techniques to Quantitatively Assess the Perfusion of the Gastric Conduit during Oesophagectomy

      In this study, four optical techniques—Optical Coherence Tomography, Sidestream Darkfield Microscopy, Laser Speckle Contrast Imaging, and Fluorescence Angiography (FA)—were compared on performing an intraoperative quantitative perfusion assessment of the gastric conduit during oesophagectomy. We hypothesised that the quantitative parameters show decreased perfusion towards the fundus in the gastric conduit and in patients with anastomotic leakage. In a prospective study in patients undergoing oesophagectomy with gastric conduit reconstruction, measurements were taken with all four optical techniques at four locations from the base towards the fundus in the gastric conduit (Loc1, Loc2, Loc3, Loc4). The primary outcome included 14 quantitative ...

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    17. Massachusetts General Hospital Receives NIH Grant for Less Invasive Assessment of Inflammation and Subepithelial Remodeling in Eosinophlic Esophagitis Patients

      Massachusetts General Hospital Receives NIH Grant for Less Invasive Assessment of Inflammation and Subepithelial Remodeling in Eosinophlic Esophagitis Patients

      Massachusetts General Hospital Receives a 2020 NIH Grant for $683,034 for Less Invasive Assessment of Inflammation and Subepithelial Remodeling in Eosinophlic Esophagitis Patients. The principal investigator is Guillermo Tearney. Below is a summary of the proposed work. Eosinophilic esophagitis (EoE) is a prevalent allergic response to food that causes eosinophilic infiltration in the esophagus. EoE can lead to esophageal remodeling, scarring, muscle hypertrophy, and stricture, decreasing quality of life and increasing risk of food impaction. Diagnosis of EoE is made by finding epithelial esophageal eosinophilia in biopsies acquired during upper endoscopy. Patients are treated with topical corticosteroids or dietary ...

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    18. A detailed comparison between the endoscopic images using blue laser imaging and three-dimensional reconstructed pathological images of colonic lesions

      A detailed comparison between the endoscopic images using blue laser imaging and three-dimensional reconstructed pathological images of colonic lesions

      Blue laser/light imaging (BLI) is an image-enhanced endoscopy (IEE) technique that can provide an accurate diagnosis by closely observing the surface structure of various colonic lesions. However, complete correspondence between endoscopic images and pathological images has not been demonstrated. The aim of this study was to accurately compare endoscopic images and the pathological images using a three-dimensionally (3D) reconstructed pathological model. Continuous thin layer sections were prepared from colonic tissue specimens and immunohistochemically stained for CD34 and CAM5.2. Three-dimensional reconstructed images were created by superimposing immunohistochemically stained pathological images. The endoscopic image with magnifying BLI was compared with ...

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    19. Optical coherence tomography imaging of excised canine apocrine gland anal sac adenocarcinoma tumors

      Optical coherence tomography imaging of excised canine apocrine gland anal sac adenocarcinoma tumors

      Optical coherence tomography (OCT) is an optical imaging modality that has been investigated for real‐time surgical margin evaluation in human breast cancer patients. Previous veterinary OCT studies have been limited to surgical margin imaging for soft tissue sarcoma (STS) tumors. To the authors knowledge, OCT has never been used to characterize or evaluate other types of neoplasia in dogs. The goal of this study was to characterize the OCT imaging appearance of apocrine gland anal sac adenocarcinoma (AGASACA) in excised ex vivo specimens from five client‐owned dogs. All excised tissue surgical margins were imaged using a clinical spectral ...

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    20. Optical coherent tomography to evaluate the degree of inflammation in a mouse model of colitis

      Optical coherent tomography to evaluate the degree of inflammation in a mouse model of colitis

      Background: There is an urgent need to develop a noninvasive imaging technique for the diagnosis of early inflammatory lesions or early and real-time microscopic assessment before selecting the most representative biopsy sites. Methods: In this study, a dextran sulfate sodium colitis model was developed, and intestinal histological damage scores measured the degree of inflammation in colitis. According to these scores, 6 parameters were designed for hematoxylin and eosin (HE) sections based on morphological changes, and 2 parameters were designed for optical coherence tomography (OCT) images to measure submucosal edema by morphological changes to evaluate inflammation degrees in the colon. Spearman ...

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    21. TRANS-SEROSAL MULTIMODAL OPTICAL COHERENCE TOMOGRAPHY FOR VISUALIZATION OF MICROSTRUCTURE AND BLOOD CIRCULATION OF THE SMALL INTESTINE WALL

      TRANS-SEROSAL MULTIMODAL OPTICAL COHERENCE TOMOGRAPHY FOR VISUALIZATION OF MICROSTRUCTURE AND BLOOD CIRCULATION OF THE SMALL INTESTINE WALL

      The aim of the study was to evaluate the performance of trans-serosal multimodal OCT (MM OCT) in in vivo detecting of changes in microstructure and blood circulation of the small intestine wall caused by arteriovenous ischemia resulted from intestine strangulation. Materials and Methods. In experiments on Wistar rats (n=22), we examined the small intestine wall in vivo using MM OCT; the access to the intestine was reached through laparotomy. The microvasculature and microstructure of the wall were studied before and after acute arteriovenous ischemia created by ligation of a small bowel segment. The results were then added with data ...

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    22. Tethered capsule en face optical coherence tomography for imaging Barrett’s esophagus in unsedated patients

      Tethered capsule en face optical coherence tomography for imaging Barrett’s esophagus in unsedated patients

      Objective Detection of Barrett’s esophagus (BE) at points of care outside the endoscopy suite may improve screening access and reduce esophageal adenocarcinoma mortality. Tethered capsule optical coherence tomography (OCT) can volumetrically image esophageal mucosa and detect BE in unsedated patients. We investigated ultrahigh-speed tethered capsule, swept-source OCT (SS-OCT) in unsedated patients, improved device design, developed procedural techniques, measured how capsule contact and longitudinal pullback non-uniformity affect coverage, and assessed patient toleration. Design OCT was performed in 16 patients prior to endoscopic surveillance/treatment. Unsedated patients swallowed the capsule with small sips of water and the esophagus imaged by retracting ...

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    23. Full-field optical coherence tomography: novel imaging technique for extemporaneous high-resolution analysis of mucosal architecture in human gut biopsies

      Full-field optical coherence tomography: novel imaging technique for extemporaneous high-resolution analysis of mucosal architecture in human gut biopsies

      Full-field optical coherence tomography (FFOCT) is an imaging technique of biological tissue based on tissue light reflectance analysis. We evaluated the feasibility of imaging fresh digestive mucosal biopsies after a quick mounting procedure (5 min) using two distinct modalities of FFOCT. In static FFOCT mode, we gained high-resolution images of general gut tissue-specific architecture, such as oesophageal papillae, gastric pits, duodenal villi and colonic crypts. In dynamic FFOCT mode, we imaged individual epithelial cells of the mucosal lining with a cellular or subcellular resolution and identified cellular components of the lamina propria. FFOCT represents a promising dye-free imaging tool for ...

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    1-24 of 649 1 2 3 4 ... 25 26 27 »
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