1. Articles in category: Gastroenterology

    1-24 of 681 1 2 3 4 ... 27 28 29 »
    1. Flexible, high-resolution micro-optical coherence tomography endobronchial probe toward in vivo imaging of cilia

      Flexible, high-resolution micro-optical coherence tomography endobronchial probe toward in vivo imaging of cilia

      We report the design and fabrication of a flexible, longitudinally scanning high-resolution micro-optical coherence tomography (μOCT) endobronchial probe, optimized for micro-anatomical imaging in airways. The 2.4 mm diameter and flexibility of the probe allows it to be inserted into the instrument channel of a standard bronchoscope, enabling real-time video guidance of probe placement. To generate a depth-of-focus enhancing annular beam, we utilized a new fabrication method, whereby a hollow glass ferrule was angle-polished and gold-coated to produce an elongated annular reflector. We present validation data that verifies the preservation of linear scanning, despite the use of flexible materials. When ...

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    2. Passively scanned, single-fiber optical coherence tomography probes for gastrointestinal devices

      Passively scanned, single-fiber optical coherence tomography probes for gastrointestinal devices

      Background/objectives: Optical coherence tomography (OCT) uses low coherence interferometry to obtain depth-resolved tissue reflectivity profiles (M-mode) and transverse beam scanning to create images of two-dimensional tissue morphology (B-mode). Endoscopic OCT imaging probes typically employ proximal or distal mechanical beam scanning mechanisms that increase cost, complexity, and size. Here, we demonstrate in the gastrointestinal (GI) tracts of unsedated human patients, that a passive, single-fiber probe can be used to guide device placement, conduct device-tissue physical contact sensing, and obtain two-dimensional OCT images via M-to-B-mode conversion. Materials and methods: We designed and developed ultrasmall, manually scannable, side- and forward-viewing single fiber-optic ...

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    3. Endoscopic optical coherence tomography angiography using inverse SNR-amplitude decorrelation features and electrothermal micro-electro-mechanical system raster scan

      Endoscopic optical coherence tomography angiography using inverse SNR-amplitude decorrelation features and electrothermal micro-electro-mechanical system raster scan

      Background: Angiogenesis is closely associated with tumor development and progression. Endoscopic optical coherence tomography angiography (OCTA) enables rapid inspection of mucosal 3D vasculature of inner organs in the early-stage tumor diagnosis; however, it is limited by instabilities of the optical signal and beam scanning. Methods: In the phase-unstable swept source OCTA (SS-OCTA), amplitude decorrelation was used to compute the motion-induced changes as motion contrast. The influence of the random noise-induced amplitude fluctuations on decorrelation was characterized as a function of inverse signal-to-noise ratio (SNR) with a multi-variate time series (MVTS) model and statistical analysis. Then, the noise-induced decorrelation artifacts in ...

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    4. Differential diagnosis of acute and chronic colitis in mice by optical coherence tomography

      Differential diagnosis of acute and chronic colitis in mice by optical coherence tomography

      Background: The differential diagnosis of acute and chronic colitis remains a common clinical problem. Optical coherence tomography (OCT) is a non-invasive, high-resolution imaging technique that can be used to measure morphological changes in the intestinal wall and estimate intestinal inflammation. We aimed to conduct an ex vivo experiment on a mouse model investigate the value of OCT as a tool for the differential diagnosis of acute and chronic colitis. Methods: Mice were administered dextran sulfate sodium salt (DSS) to construct acute and chronic colitis models. Acutely- and chronically-affected intestinal walls were scanned by OCT, and then the scanned colonic tissue ...

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    5. Apparatus, device and method for capsule microscopy

      Apparatus, device and method for capsule microscopy

      An exemplary apparatus for obtaining data for at least one portion within at least one luminal or hollow sample can be provided. For example, the apparatus can include a first optical arrangement configured to transceive at least one electromagnetic radiation to and from the portion(s). The apparatus can also include a wavelength dispersive second arrangement, which can be configured to disperse the electromagnetic radiation(s). A housing can be provided with a shape of a pill, and enclosing the first and second arrangements.

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    6. Esophageal optical coherence tomography image synthesis using an adversarially learned variational autoencoder

      Esophageal optical coherence tomography image synthesis using an adversarially learned variational autoencoder

      Endoscopic optical coherence tomography (OCT) imaging offers a non-invasive way to detect esophageal lesions on the microscopic scale, which is of clinical potential in the early diagnosis and treatment of esophageal cancers. Recent studies focused on applying deep learning-based methods in esophageal OCT image analysis and achieved promising results, which require a large data size. However, traditional data augmentation techniques generate samples that are highly correlated and sometimes far from reality, which may not lead to a satisfied trained model. In this paper, we proposed an adversarial learned variational autoencoder (AL-VAE) to generate high-quality esophageal OCT samples. The AL-VAE combines ...

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    7. Dual-mode endoscope offers unprecedented insights into uterine health

      Dual-mode endoscope offers unprecedented insights into uterine health

      Researchers have developed a new endoscope that combines ultrasound with optical coherence tomography (OCT) to assess structural features of the lining of the uterus, called the endometrium, in unprecedented detail. The new probe could one day help doctors diagnose infertility problems that are related to endometrial receptivity with greater accuracy than current imaging technologies while reducing the need for invasive biopsies.

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    8. Integrated US-OCT-NIRF Tri-modality Endoscopic Imaging System for Pancreaticobiliary Duct Imaging

      Integrated US-OCT-NIRF Tri-modality Endoscopic Imaging System for Pancreaticobiliary Duct Imaging

      Pancreaticobiliary carcinomas is a highly malignant gastrointestinal tumor. Most pancreaticobiliary cancers arise from epithelial proliferations within the pancreaticobiliary ducts, referred to as pancreatic intraepithelial neoplasias (PanINs). Some PanINs are benign metaplasia, while others progress to invasive duct adenocarcinoma (IDAC). However, there is no standard programme to diagnose the progression from PanINs to IDAC. In this study, we present a tri-modality imaging system, which integrates ultrasound (US), optical coherence tomography (OCT), and near-infrared fluorescence (NIRF) for pancreaticobiliary duct imaging. This system can obtain OCT, US, and NIRF images in real time with a frame rate of 30 frames per second. For ...

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    9. Today’s Mistakes and Tomorrow’s Wisdom in Endoscopic Imaging of Barrett’s Esophagus

      Today’s Mistakes and Tomorrow’s Wisdom in Endoscopic Imaging of Barrett’s Esophagus

      Background: Esophageal adenocarcinoma (EAC) is one of the main causes of cancer-related deaths worldwide and its incidence is rising. Barrett’s esophagus (BE) can develop low- and high-grade dysplasia which can progress to EAC overtime. The golden standard to detect dysplastic BE (DBE) or EAC is surveillance with high-definition white-light endoscopy (HD-WLE) and random biopsies according to the Seattle protocol. However, this method is time-consuming and associated with a remarkable miss rate. Therefore, there is great need for the development of novel reliable techniques to optimize surveillance strategies and improve detection rates. Summary: Optical chromoendoscopy (OC) techniques like narrow-band imaging ...

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    10. Classification of gastric cancerous tissues by a residual network based on optical coherence tomography images

      Classification of gastric cancerous tissues by a residual network based on optical coherence tomography images

      Optical coherence tomography (OCT) is a noninvasive, radiation-free, and high-resolution imaging technology. The intraoperative classification of normal and cancerous tissue is critical for surgeons to guide surgical operations. Accurate classification of gastric cancerous OCT images is beneficial to improve the effect of surgical treatment based on the deep learning method. The OCT system was used to collect images of cancerous tissues removed from patients. An intelligent classification method of gastric cancerous tissues based on the residual network is proposed in this study and optimized with the ResNet18 model. Four residual blocks are used to reset the model structure of ResNet18 ...

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    11. Spectroscopic Optical Coherence Tomography for Classification of Colorectal Cancer in a Mouse Model

      Spectroscopic Optical Coherence Tomography for Classification of Colorectal Cancer in a Mouse Model

      Noninvasive diagnosis of the malignant potential of colon polyps can improve prevention of colorectal cancer without the need for time-consuming and expensive biopsies. This study examines the use of spectroscopic optical coherence tomography (OCT) to classify tissue from genetically engineered mouse models of early-stage adenoma (APC) and advanced adenocarcinoma (AKP) in which tumors are induced in the distal colon. The optical tissue properties of scattering power and scattering attenuation coefficient are evaluated by analyzing the imaging data collected from tissues. Classifications are generated using 2D linear discriminant analysis with high levels of discrimination obtained. The overall classification accuracy obtained was ...

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      Mentions: Duke University
    12. Advanced Imaging of the Biliary System and Pancreas

      Advanced Imaging of the Biliary System and Pancreas

      Despite advances in noninvasive techniques for imaging the pancreaticobiliary system, several disease processes including indeterminate biliary strictures as well as neuroendocrine tumors, inflammatory pseudotumors, and complex cysts of the pancreas remain difficult to characterize. New endoscopic imaging technologies have emerged to address these challenges. Cholangioscopy and intraductal ultrasound (IDUS) are powerful tools to characterize subtle biliary concretions and strictures. Confocal Laser Endomicroscopy (CLE) and Optical Coherence Tomography (OCT) are emerging approaches for the most difficult biliary lesions. Contrast harmonic endoscopic ultrasound (CH-EUS), elastography, and 3D-EUS are improving the approach to subtle pancreatic lesions, particularly in the context of indeterminate tissue ...

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    13. Human Colorectal Cancer Tissue Assessment Using Optical Coherence Tomography Catheter and Deep Learning

      Human Colorectal Cancer Tissue Assessment Using Optical Coherence Tomography Catheter and Deep Learning

      Optical coherence tomography (OCT) can differentiate normal colonic mucosa from neoplasia, potentially offering a new mechanism of endoscopic tissue assessment and biopsy targeting, with a high optical resolution and an imaging depth of ~1 mm. Recent advances in convolutional neural networks (CNN) have enabled application in ophthalmology, cardiology, and gastroenterology malignancy detection with high sensitivity and specificity. Here we describe a miniaturized OCT catheter and a residual neural network (ResNet)-based deep learning model manufactured and trained to perform automatic image processing and real-time diagnosis of the OCT images. The OCT catheter has an outer diameter of 3.8 mm ...

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    14. Esophageal OCT Imaging Using a Paddle Probe Externally Attached to Endoscope

      Esophageal OCT Imaging Using a Paddle Probe Externally Attached to Endoscope

      Background and aims: Endoscopic surveillance of Barrett's esophagus (BE) by white light examination is insufficient to diagnose dysplastic change. In this work, we describe an optical imaging method to obtain high-resolution cross-sectional imaging using a paddle-shaped probe affixed to the endoscope tip. Methods: We integrated Optical Coherence Tomography (OCT), an optical imaging method that produces cross-sectional images, into a paddle probe attached to video endoscope. We acquired images of esophageal epithelium from patients undergoing routine upper GI endoscopy. Images were classified by a reviewer blinded to patient identity and condition, and these results were compared with clinical diagnosis. Results ...

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    15. Prediction of Neoplastic Progression in Barrett’s Esophagus Using Nanoscale Nuclear Architecture Mapping: A Pilot Study

      Prediction of Neoplastic Progression in Barrett’s Esophagus Using Nanoscale Nuclear Architecture Mapping: A Pilot Study

      Background and Aims Nanoscale nuclear architecture mapping (nanoNAM), an optical coherence tomography-derived approach, is capable of detecting with nanoscale sensitivity, structural alterations in the chromatin of epithelial cell nuclei at risk for malignant transformation. Since these alterations predate the development of dysplasia, we aimed to utilize nanoNAM to identify patients with Barrett’s esophagus (BE) who progress to high grade dysplasia (HGD) or esophageal adenocarcinoma (EAC). Methods This is a nested case control study of 46 BE patients of which 21 progressed to HGD/EAC over 3.7 (± 2.37) years (cases/progressors) and 25 patients who did not progress ...

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    16. Endoscopic Optical Coherence Tomography for Screening and Diagnosis of Colorectal Precancerous and Malignant Polyps

      Endoscopic Optical Coherence Tomography for Screening and Diagnosis of Colorectal Precancerous and Malignant Polyps

      Colorectal cancer arises from the mucosal layer of the colon. Current screening is performed by flexible endoscopy, which involves visual inspection of the mucosal lining of the colon and rectum with an optical camera mounted on the endoscope, with abnormal areas being biopsied. This method is somewhat limited in that there are no readily available surface pattern or morphological classification systems with adequate sensitivity or specificity to evaluate extent of submucosal invasion (deep, superficial, or none). Optical coherence tomography (OCT) using pattern recognition is a high-resolution imaging modality. There is currently an unmet need to predict depth of invasion for ...

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    17. Massachusetts General Hospital Receive NIH Grant for A tethered capsule endoscopic-endomicroscopic (TEEM) approach for improving upper GI tract diagnosis

      Massachusetts General Hospital Receive NIH Grant for A tethered capsule endoscopic-endomicroscopic (TEEM) approach for improving upper GI tract diagnosis

      Massachusetts General Hospital Received a 2022 NIH Grant for $480,931 for A tethered capsule endoscopic-endomicroscopic (TEEM) approach for improving upper GI tract diagnosis. The principal investigator is Guillermo Tearney. Below is a summary of the proposed work. The diagnosis of most upper GI tract conditions is currently accomplished by upper endoscopy with biopsy (EGD). EGD is costly primarily because it requires conscious sedation, necessitating that procedures be conducted by physicians in a specialized endoscopy suite, and that patients take time away from work and family. Another limitation is sampling error - endoscopic biopsies are frequently random, resulting in many instances ...

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    18. Connectivity-based deep learning approach for segmentation of the epithelium in in vivo human esophageal OCT images

      Connectivity-based deep learning approach for segmentation of the epithelium in in vivo human esophageal OCT images

      Optical coherence tomography (OCT) is used for diagnosis of esophageal diseases such as Barrett's esophagus. Given the large volume of OCT data acquired, automated analysis is needed. Here we propose a bilateral connectivity-based neural network for in vivo human esophageal OCT layer segmentation. Our method, connectivity-based CE-Net (Bicon-CE), defines layer segmentation as a combination of pixel connectivity modeling and pixel-wise tissue classification. Bicon-CE outperformed other widely used neural networks and reduced common topological prediction issues in tissues from healthy patients and from patients with Barrett's esophagus. This is the first end-to-end learning method developed for automatic segmentation of ...

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    19. Spotting colon cancer early with the 'Google Earth of colonoscopies'

      Spotting colon cancer early with the 'Google Earth of colonoscopies'

      A new optical imaging system in the works could revolutionize the diagnosis of colon cancer. Currently, colonoscopies only manage to detect 39 % of bowel cancer cases in the early stages. Now, the EU-funded PROSCOPE project's novel screening platform has the potential to save up to half of the 160 000 lives lost in Europe every year because of this disease. Today's colonoscopy procedures are based on white light video or optical narrow-band imaging.

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    20. Optical coherence tomography of small intestine allograft biopsies using a handheld surgical probe

      Optical coherence tomography of small intestine allograft biopsies using a handheld surgical probe

      Significance: The current gold standard for monitoring small intestinal transplant (IT) rejection is endoscopic visual assessment and biopsy of suspicious lesions; however, these lesions are only superficially visualized by endoscopy. Invasive biopsies provide a coarse sampling of tissue health without depicting the true presence and extent of any pathology. Optical coherence tomography (OCT) presents a potential alternative approach with significant advantages over traditional white-light endoscopy. Aim: The aim of our investigation was to evaluate OCT performance in distinguishing clinically relevant morphological features associated with IT graft failure. Approach: OCT was applied to evaluate the small bowel tissues of two rhesus ...

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    21. Massachusetts General Hospital Receives NIH Grant for Volumetric mapping of tissue microstructure with OCT for enhanced dysplasia detection

      Massachusetts General Hospital Receives NIH Grant for Volumetric mapping of tissue microstructure with OCT for enhanced dysplasia detection

      Massachusetts General Hospital Receives a 2021 NIH Grant for $46,036 for Volumetric mapping of tissue microstructure with OCT for enhanced dysplasia detection. The principal investigator is Taylor Cannon. Below is a summary of the proposed work. Better imaging-based screening and surveillance methods stand to improve patient outcomes in cancers that are typically diagnosed at late stages, such as esophageal adenocarcinoma (EAC). Although success- ful proactive treatment options are available to patients diagnosed with low- or high-grade dysplasia, many at-risk patients are diagnosed at later stages with few effective treatment options, leading to high mortality rates. Dysplasia is diagnosed based ...

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    22. PROSCOPE project aims for early-stage bowel cancer detection

      PROSCOPE project aims for early-stage bowel cancer detection

      Multimodal platform should allow cellular-level colon imaging in real-time. Improving diagnosis: PROSCOPE A project funded by the EU's Horizon 2020 program is on course to develop a new imaging system for the diagnosis of bowel cancer. PROSCOPE , officially titled "Point-of-care instrument for diagnosis and image-guided intervention of colorectal cancer," was launched in 2020 and backed by €6 million of EU funding. The project has now carried out an 18-month formal review, confirming that its research program is on target to help reduce the 160,000 deaths and €9 billion in healthcare costs associated with the disease. "Currently, only 14 ...

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    23. New imaging system to detect bowel cancer at the earliest stages using photonics

      New imaging system to detect bowel cancer at the earliest stages using photonics

      Early intervention could prevent many of the 160,000 deaths from colon cancer in Europe each year. Colonoscopies, the gold standard for spotting bowel cancer early, can still miss up to 20% of precancerous cells. But now, thanks to a pan-European health consortium, a new concept that uses photonics to help doctors spot bowel cancer could soon prevent up to half of these deaths and save €9 billion in reduced healthcare costs. No tools exist that can look inside the colon at the cellular level in real-time to give an immediate diagnosis. But now, this European research team based across ...

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    24. A novel biliopancreatic duct endoscope combined optical coherence tomography with intraductal ultrasonography for exploring the bile duct: a diagnostic study in a porcine model

      A novel biliopancreatic duct endoscope combined optical coherence tomography with intraductal ultrasonography for exploring the bile duct: a diagnostic study in a porcine model

      Background and Aims There are many deficiencies of existing biliopancreatic duct endoscopy in the examination of early biliary and pancreatic tumors. This study aimed to evaluate the usefulness and feasibility of a novel ultrafine separable biliopancreatic duct endoscopy device with dual modalities of intraductal ultrasonography (IDUS) and optical coherence tomography (OCT) for the in vivo assessment of biliopancreatic duct system during ERCP. Methods Five Bama miniature pigs were selected to probe their common bile duct and branches by using this novel equipment during ERCP. The feasibility of the procedure was evaluated by clear, clinically interpretable images obtained by using spiral ...

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