Gastroenterology

Study on the application of optical coherence microscopy in Hirschsprung’s disease

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Study on the application of optical coherence microscopy in Hirschsprung's disease To explore the clinical application value of optical coherence microscopy (OCM) in Hirschsprung’s disease. 109 HSCR patients were recuited in a Chinese hospital from January 2018 to July 2021. All the recruited patients underwent barium enema angiography preoperatively and the resected diseased intestinal tubes were evaluated intraoperatively. The OCM and the histopathological examination were performed successively on the surgical specimens, and the OCM images were compared with the relevant tissue sections to characterize different lesions. 10 non-HSCR fetal colorectal tissues at the same period were retained for OCM, the characteristics of which with and without HSCR under OCM imaging were analyzed. In the OCM images of in vitro tissue, it can be clearly observed that the scattering degree of HSCR narrow segment mucosal is high, glands and crypt structures are reduced or even atrophy, and the scattering degree of submucosal and intermuscular is low; In the dilated segment, the ...

Automatic intraluminal scanning with a steerable endoscopic optical coherence tomography catheter for gastroenterology applications

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Significance Endoscopic optical coherence tomography (OCT) enables real-time optical biopsy of human organs. Endoscopic probes require miniaturization of optics, which in turn limits field of view. When larger imaging areas are needed such as in the gastrointestinal tract, the operator must manually scan the probe over the tissue to extend the field of view, often resulting in an imperfect scanning pattern and increased risk of missing lesions. Automatic scanning has the potential to extend the field of view of OCT, allowing the user to focus on image interpretation during real-time observations. Aim This work proposes an automatic scanning using a steerable OCT catheter integrated with a robotized interventional flexible endoscope. The aim is to extend the field of view of a low-profile OCT probe while improving scanning accuracy and maintaining a stable endoscope’s position during minimally invasive treatment of colorectal lesions. Approach A geometrical model of the steerabl...

Endoscopy for Barrett’s Esophagus

A variety of other advanced imaging technologies have been applied to BE surveillance in the last 20 years. Optical coherence tomography, available in the past in both probe- and balloon-based wide-field applications, can detect both abnormalities consistent with BE, as well as tissue characteristics associated with dysplasia.29 Concerns about cost, accuracy,30 additional time to apply the imaging, and availability of tools have limited the use of these modalities. Autofluorescence imaging relies on the property of neoplastic tissue to emit light of a longer wavelength when it is excited by light of a shorter wavelength.31 Studies show that this modality may aid in detecting or delineating neoplasia, although again, accuracy may be suboptimal,32 and the incremental value over a high-definition white light exam is unclear. Confocal laser endomicroscopy, available as a through-the-scope probe, allows real-time characterization of the esophageal mucosa but requires ...

A protocol paper for the MOTION Study—A longitudinal study in a cohort aged 60 years and older to obtain mechanistic knowledge of the role of the gut microbiome during normal healthy ageing in order to develop strategies that will improve lifelong health

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Background Advances in medicine and public health mean that people are living longer; however, a significant proportion of that increased lifespan is spent in a prolonged state of declining health and wellbeing which places increasing pressure on medical, health and social services. There is a social and economic need to develop strategies to prevent or delay age-related disease and maintain lifelong health. Several studies have suggested links between the gut microbiome and age-related disease, which if confirmed would present a modifiable target for intervention development. The MOTION study aims to determine whether and how changes in the gut microbiome are associated with physical and mental capacity. A comprehensive longitudinal multiparameter study such as this has not been previously undertaken. Methods MOTION is a longitudinal prospective cohort study with a focus on gut health and cognitive function. 360 healthy individuals aged 60 years and older, living in East Anglia, UK...

Swept-source endoscopic optical coherence tomography real-time imaging system based on GPU acceleration for axial megahertz high-speed scanning

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Objective: In order to solve the problem of image real-time processing and correction for high-speed endoscopic swept-source optical coherence tomography (SS-OCT), we highly optimize a computer-unified device architecture-based platform and use a field-programmable gate array to summarize the application experience. Materials and methods: We use the Half-Sync/Half-Asyn mode to optimize memory in order to build a high-throughput data thread pool for CPU. We use asynchronous streaming architecture to multiplex multiple threads at high speed to accelerate data processing. At the same time, we design a rotary scanning position information encoding feedback module to suppress image drift, which can realize 25ns logic-timing sequence synchronization control through FPGA 40MHz clock. Results: The maximum complete attainable axial-scan-processing rate (including memory transfer and display of B-scan frames) is 3.52 MHz for a 16-bit pixel depth and A-scans/s of 1024 pixels. To our knowledge,...

How to improve microendoscopes? New probe design brings promises to improve biomedical imaging

Microendoscopes are the cornerstone of modern medical diagnostics—they allow us to see what we could not even describe two decades ago. The technology is constantly improving, with ICTER scientists contributing to the development of the probes. Microendoscopes using fiber optics are becoming increasingly important imaging tools, but they have physical limitations. They are essential for applications that require a long working distance, high resolution, and a minimum probe diameter. A new research paper by Dr. Karol Karnowski of ICTER, Dr. Gavrielle Untracht of the Technical University of Denmark (DTU), Dr. Michael Hackmann of the University of Western Australia (UWA), Onur Cetinkaya of ICTER and Prof. David Sampson of the University of Surrey, sheds new light on modern microendoscopes. The research work started while the authors worked in the same research group at UWA. ( Read Full Article )

Attenuation coefficient for layer-by-layer assessment of the intestinal wall in acute ischemia according to optical coherence tomography

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Small laboratory animals (rats) are suitable objects for modelling acute mesenteric ischemia (AMI) and monitoring changes in the structural tissue and intramural blood flow using optical coherence tomography (OCT) and OCT angiography methods. Combined with evaluation of blood circulation the prevalence of a necrotic tissue is a key factor in assessing intestine viability during surgery and determining the resection margins. While the assessment of the blood vessels network is commonly performed visually by surgeons, the assessment of the necrosis within individual layers is quite challenging due to small thickness of each intestine layer in small objects. The study demonstrates that the construction of colour-coded maps of the tissue attenuation coefficient estimated from the OCT data, allows quick layer-by-layer evaluation of the intestine wall. Such maps in the AMI model make it possible to track changes separately in the serous-muscular, submucosa and mucosa layers of the intesti...

Development of Advanced Imaging and Molecular Imaging for Barrett’s Neoplasia

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Barrett esophagus (BE) is a precursor to a life-threatening esophageal adenocarcinoma (EAC). Surveillance endoscopy with random biopsies is recommended for early intervention against EAC, but its adherence in the clinical setting is poor. Dysplastic lesions with flat architecture and patchy distribution in BE are hardly detected by high-resolution endoscopy, and the surveillance protocol entails issues of time and labor and suboptimal interobserver agreement for diagnosing dysplasia. Therefore, the development of advanced imaging technologies is necessary for Barrett’s surveillance. Recently, non-endoscopic or endoscopic technologies, such as cytosponge, endocytoscopy, confocal laser endomicroscopy, autofluorescence imaging, and optical coherence tomography/volumetric laser endomicroscopy, were developed, but most of them are not clinically available due to the limited view field, expense of the equipment, and significant time for the learning curve. Another strategy is focuse...

Massachusetts General Hosptial Receives NIH Grant for Screening for Barrett’s Esophagus Progressors with Multimodality Tethered Capsule Image-Guided Biopsy

Massachusetts General Hosptial Received a 2022 NIH Grant for $643,503 for Screening for Barrett's Esophagus Progressors with Multimodality Tethered Capsule Image-Guided Biopsy. The principal investigator is Guillermo Tearney. Below is a summary of the proposed study. Esophageal adenocarcinoma (EAC) is a deadly cancer that is preceded by a metaplastic change called Barrett's esophagus (BE). It has long been thought that endoscopic screening for BE followed by endoscopic surveillance can significantly decrease the mortality of EAC. This unfortunately has not borne out as the cost and inconvenience of conscious sedation prohibits endoscopy from being used as a population-based screening tool. BE screening may become possible in the future, owing to innovative swallowable tethered capsule endomicroscopes or cell sampling devices that can detect BE without requiring sedation. Yet, even if these capsules were to identify the large number of people in the US who have BE (~15M), endoscopic ...

En-face polarization-sensitive optical coherence tomography to characterize early-stage esophageal cancer and determine tumor margin

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Current imaging tools are insufficiently sensitive to the early diagnosis of esophageal squamous cell carcinoma (ESCC). The application of polarization-sensitive optical coherence tomography (PS-OCT) to detect tumor-stroma interaction is an interesting issue in cancer diagnosis. In this translational study, we found that en-face PS-OCT effectively characterizes protruding, flat, and depressive type ESCC regardless of animal or human specimens. In addition, the tumor contour and margin could also be drawn and determined on a broad en-face view. The determined tumor margin could be in the proximity of 2 mm to the actual tumor margin, which was proved directly using histology. ( Read Full Article )

Comparative Study of Conventional and Ultrahigh-resolution Optical Coherence Tomography Imaging in Esophageal Neoplasia

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Early diagnosis of esophageal cancer can be enhanced by the application of optical coherence tomography (OCT) to gastrointestinal endoscopy. One of the most salient examples is the use of OCT to augment the detection of dysplasia during Barrett's esophagus (BE) surveillance, the established precursor to esophageal adenocarcinoma (EAC). 1 , 2 A previously commercially available balloon-based imaging catheter system, also known as volumetric laser endomicroscopy (VLE), was designed to provide circumferential esophageal imaging at the time of endoscopy. The VLE system uses a 1300 nm wavelength-swept laser and provides images with an axial resolution of 7 µm up to a depth of 3 mm. VLE is capable of resolving microarchitectural features associated with early neoplasia in BE including irregular glandular morphology and increased surface signal intensity. 3 Scoring systems that incorporate these features are associated with a sensitivity of 76-83% and specificity of 71-79% in the dia...

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

Massachusetts General Hosptial Received a 2022 NIH Grant for $46,752 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 successful 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 on histological evaluation of esophageal biopsies taken under the guidance of white light endoscopy (WLE), which in itself does not have the resolution to detect the key morphological changes, namely increases in nuclear size and nuclear cytoplasmic ratio (NCR), that characterize dysplastic p...

First interobserver agreement of optical coherence tomography in the bile duct: A multicenter collaborative study

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Background and study aims  Optical coherence tomography (OCT) is a new technology available for evaluation of indeterminate biliary strictures. It allows under-the-surface visualization and preliminary studies have confirmed standardized characteristics associated with malignancy. The aim of this study is to evaluate the first interobserver agreement in identifying previously agreed upon OCT criteria and diagnosing of malignant versus benign disease. Patients and methods  Fourteen endoscopists were asked to review an atlas of reference clips and images of eight criteria derived from expert consensus A total of 35 de-identified video clips were then evaluated for presence of the eight criteria and for final diagnosis of malignant versus benign using the atlas as reference Intraclass correlation (ICC) analysis was done to evaluate interrater agreement. Results  Clips of 23 malignant lesions and 12 benign lesions were scored. Excellent interobserver agreement was seen wi...

Soluplus®-based dissolving microarray patches loaded with colchicine: towards a minimally invasive treatment and management of gout

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Considered as one of the most common inflammatory arthritis, gout is characterised by a sudden onset of severe joint pain. As the first-line drug of choice used in treating acute gout, colchicine (CLC) is hindered by poor gastrointestinal permeability as well as unfavourable gastrointestinal side effects. Herein, we present, for the first time, the preparation of microarray array patches (MAPs) made of a polymeric solubiliser, Soluplus®, loaded with CLC for its systemic delivery. The fabricated MAPs displayed acceptable mechanical properties and were capable of being inserted into the skin to a depth of ≈500 μm in full thickness ex vivo neonatal porcine skin, as evidenced by optical coherence tomography. In vitro dermatokinetic studies utilising full thickness neonatal porcine skin demonstrated that the CLC-loaded MAPs delivered CLC across all skin strata, resulting in a delivery efficiency of 73% after 24 hours. Furthermore, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl te...

Pairing imaging, AI may improve colon cancer screening, diagnosis

A research team from the lab of Quing Zhu, the Edwin H. Murty Professor of Engineering at the McKelvey School of Engineering at Washington University in St. Louis, has combined optical coherence tomography (OCT) and machine learning to develop a colorectal cancer imaging tool that may one day improve the traditional endoscopy currently used by doctors. The results were published in the June issue of the Journal of Biophotonics, with an image featured on the inside cover. ( Read Full Article )

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