All Articles from Tsung-Han Tsai -Optical Coherence Tomography News

Articles from Tsung-Han Tsai

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1. Imaging Apparatus With Balloon And Shaped Tip
  
  Explore patentscope.wipo.int Jun 15 2018 Patents , Probes
  
  Exemplary imaging apparatuses are described. Various imaging apparatuses may implement optical coherence tomography (OCT) and/or optical frequency domain imaging (OFDI) gastrointestinal tissue imaging methods and technologies. Furthermore, the imaging apparatuses may include a rotatable imaging element to scan a bodily lumen, such as the esophagus. The imaging element may be housed within an inflatable balloon. Still further, the imaging apparatuses may include a shaped tip. The shaped tip may aid in guiding an imaging apparatus through the esophagus, or other bodily lumen.
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  Mentions: NinePoint Medical Eman Namati
2. Optical coherence tomography in gastroenterology: a review and future outlook
  
  Explore SPIE Digital Library Dec 19 2017 Gastroenterology
  
  Optical coherence tomography (OCT) is an imaging technique optically analogous to ultrasound that can generate depth-resolved images with micrometer-scale resolution. Advances in fiber optics and miniaturized actuation technologies allow OCT imaging of the human body and further expand OCT utilization in applications including but not limited to cardiology and gastroenterology. This review article provides an overview of current OCT development and its clinical utility in the gastrointestinal tract, including disease detection/differentiation and endoscopic therapy guidance, as well as a discussion of its future applications.
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  Mentions: Columbia University Massachusetts General Hospital Harvard University
3. Endoscopic forward-viewing optical coherence tomography and angiography with MHz swept source
  
  Explore OSA | OSA Publishing Aug 9 2017 Gastroenterology , Probes
  
  Endoscopic optical coherence tomography (OCT) instruments are mostly side viewing and rely on at least one proximal scan, thus limiting accuracy of volumetric imaging and en face visualization. Previous forward-viewing OCT devices had limited axial scan speeds. We report a forward-viewing fiber scanning 3D-OCT probe with 900 μm field of view and 5 μm transverse resolution, imaging at 1 MHz axial scan rate in the human gastrointestinal tract. The probe is 3.3 mm diameter and 20 mm rigid length, thus enabling passage through the endoscopic channel. The scanner has 1.8 kHz resonant frequency, and each volumetric acquisition takes ...
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  Mentions: Massachusetts Institute of Technology James G. Fujimoto Thorlabs
4. Assessment of the radiofrequency ablation dynamics of esophageal tissue with optical coherence tomography
  
  Explore SPIE | Journal Jul 10 2017 Gastroenterology
  
  Radiofrequency ablation (RFA) is widely used for the eradication of dysplasia and the treatment of early stage esophageal carcinoma in patients with Barrett’s esophagus (BE). However, there are several factors, such as variation of BE epithelium (EP) thickness among individual patients and varying RFA catheter-tissue contact, which may compromise RFA efficacy. We used a high-speed optical coherence tomography (OCT) system to identify and monitor changes in the esophageal tissue architecture from RFA. Two different OCT imaging/RFA application protocols were performed using an ex vivo swine esophagus model: (1) post-RFA volumetric OCT imaging for quantitative analysis of the coagulum ...
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  Mentions: Massachusetts Institute of Technology James G. Fujimoto Harvard University
5. Feature Of The Week 03/08/2015: Endoscopic Optical Coherence Angiography Enables Three Dimensional Visualization of Subsurface Microvasculature
  
  Explore Optical Coherence Tomography News Mar 7 2015 Gastroenterology
  
  Endoscopic imaging technologies such as confocal laser endomicroscopy (CLE) and narrowband imaging (NBI) have been used to investigate vascular changes as hallmarks of early cancer in the GI tract. However, the limited frame rate and field of view make CLE imaging sensitive to motion artifacts, whereas NBI has limited resolution and visualizes only the surface vascular pattern. Endoscopic optical coherence tomography (OCT) enables high speed volumetric imaging of subsurface features at near-microscopic resolution, and can image microvasculature without exogenous contrast agents such as fluorescein, which obliterates the image in areas of bleeding, or after biopsies and resections. OCT has been ...
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  Mentions: Massachusetts Institute of Technology James G. Fujimoto Thorlabs
6. Endoscopic Optical Coherence Angiography Enables Three Dimensional Visualization of Subsurface Microvasculature
  
  Explore Gastroenterology Dec 1 2014 Gastroenterology
  
  Endoscopic imaging technologies such as confocal laser endomicroscopy1 and narrow band imaging (NBI)2 have been used to investigate vascular changes as hallmarks of early cancer in the gastrointestinal tract. However, the limited frame rate and field of view make confocal laser endomicroscopy imaging sensitive to motion artifacts, whereas NBI has limited resolution and visualizes only the surface vascular pattern. Endoscopic optical coherence tomography (OCT) enables high-speed volumetric imaging of subsurface features at near-microscopic resolution,3, 4 and can image microvasculature without exogenous contrast agents,5 such as fluorescein, which obliterates the image in areas of bleeding, or after ...
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  Mentions: Massachusetts Institute of Technology James G. Fujimoto Thorlabs
7. Ultrahigh speed endoscopic optical coherence tomography for gastroenterology
  
  Explore opticsinfobase.org Nov 29 2014 Gastroenterology
  
  We describe an ultrahigh speed endoscopic swept source optical coherence tomography (OCT) system for clinical gastroenterology using a vertical-cavity surface-emitting laser (VCSEL) and micromotor imaging catheter. The system had a 600 kHz axial scan rate and 8 µm axial resolution in tissue. Imaging was performed with a 3.2 mm diameter imaging catheter at 400 frames per second with a 12 µm spot size. Three-dimensional OCT (3D-OCT) imaging was performed in patients with a cross section of pathologies undergoing upper and lower endoscopy. The use of distally actuated imaging catheters enabled OCT imaging with more flexibility, such as volumetric imaging ...
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  Mentions: Massachusetts Institute of Technology James G. Fujimoto Thorlabs
8. Correction of rotational distortion for catheter-based en face OCT and OCT angiography
  
  Explore opticsinfobase.org Oct 10 2014
  
  We demonstrate a computationally efficient method for correcting the nonuniform rotational distortion (NURD) in catheter-based imaging systems to improve endoscopic en face optical coherence tomography (OCT) and OCT angiography. The method performs nonrigid registration using fiducial markers on the catheter to correct rotational speed variations. Algorithm performance is investigated with an ultrahigh-speed endoscopic OCT system and micromotor catheter. Scan nonuniformity is quantitatively characterized, and artifacts from rotational speed variations are significantly reduced. Furthermore, we present endoscopic en face OCT and OCT angiography images of human gastrointestinal tract in vivo to demonstrate the image quality improvement using the correction algorithm.
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  Mentions: Massachusetts Institute of Technology James G. Fujimoto Thorlabs
9. Endoscopic Optical Coherence Angiography Enables 3-Dimensional Visualization of Subsurface Microvasculature
  
  Explore Gastroenterology Aug 26 2014 Gastroenterology
  
  Endoscopic imaging technologies such as confocal laser endomicroscopy 1 and narrow band imaging (NBI) 2 have been used to investigate vascular changes as hallmarks of early cancer in the gastrointestinal tract. However, the limited frame rate and field of view make confocal laser endomicroscopy imaging sensitive to motion artifacts, whereas NBI has limited resolution and visualizes only the surface vascular pattern. Endoscopic optical coherence tomography (OCT) enables high-speed volumetric imaging of subsurface features at near-microscopic resolution, 3,4 and can image microvasculature without exogenous contrast agents, 5 such as fluorescein, which obliterates the image in areas of bleeding, or after ...
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  Mentions: Massachusetts Institute of Technology James G. Fujimoto Thorlabs
10. Endoscopic Optical Coherence Tomography for Clinical Gastroenterology
  
  Explore MDPI Open Access Journals Platform May 10 2014 Gastroenterology
  
  Optical coherence tomography (OCT) is a real-time optical imaging technique that is similar in principle to ultrasonography, but employs light instead of sound waves and allows depth-resolved images with near-microscopic resolution. Endoscopic OCT allows the evaluation of broad-field and subsurface areas and can be used ancillary to standard endoscopy, narrow band imaging, chromoendoscopy, magnification endoscopy, and confocal endomicroscopy. This review article will provide an overview of the clinical utility of endoscopic OCT in the gastrointestinal tract and of recent achievements using state-of-the-art endoscopic 3D-OCT imaging systems.
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  Mentions: Massachusetts Institute of Technology James G. Fujimoto Harvard University
11. Ultrahigh speed endoscopic swept source optical coherence tomography using a VCSEL light source and micromotor catheter
  
  Explore Conference Proceedings Mar 8 2014 Gastroenterology
  
  We developed an ultrahigh speed endoscopic swept source optical coherence tomography (OCT) system for clinical gastroenterology using a vertical-cavity surface-emitting laser (VCSEL) and micromotor based imaging catheter, which provided an imaging speed of 600 kHz axial scan rate and 8 μm axial resolution in tissue. The micromotor catheter was 3.2 mm in diameter and could be introduced through the 3.7 mm accessory port of an endoscope. Imaging was performed at 400 frames per second with an 8 μm spot size using a pullback to generate volumetric data over 16 mm with a pixel spacing of 5 μm in ...
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  Mentions: Massachusetts Institute of Technology James G. Fujimoto Thorlabs
12. Compact piezoelectric transducer fiber scanning probe for optical coherence tomography
  
  Explore opticsinfobase.org Jan 2 2014 Probes
  
  We developed a compact, optical fiber scanning piezoelectric transducer (PZT) probe for endoscopic and minimally invasive optical coherence tomography (OCT). Compared with previous forward-mount fiber designs, we present a reverse-mount design that achieves a shorter rigid length. The fiber was mounted at the proximal end of a quadruple PZT tube and scanned inside the hollow PZT tube to reduce the probe length. The fiber resonant frequency was 338 Hz using a 17-mm-long fiber. A 0.9 mm fiber deflection was achieved with a driving amplitude of 35 V. Using a GRIN lens-based optical design with a 1.3 × magnification, a ...
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  Mentions: Johns Hopkins University Massachusetts Institute of Technology James G. Fujimoto
13. Swept source optical coherence microscopy using a 1310 nm VCSEL light source
  
  Explore opticsinfobase.org Jul 22 2013 Microscopy
  
  We demonstrate high speed, swept source optical coherence microscopy (OCM) using a MEMS tunable vertical cavity surface-emitting laser (VCSEL) light source. The light source had a sweep rate of 280 kHz, providing a bidirectional axial scan rate of 560 kHz. The sweep bandwidth was 117 nm centered at 1310 nm, corresponding to an axial resolution of 13.1 µm in air, corresponding to 8.1 µm (9.6 µm spectrally shaped) in tissue. Dispersion mismatch from different objectives was compensated numerically, enabling magnification and field of view to be easily changed. OCM images were acquired with transverse resolutions between 0 ...
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  Mentions: Massachusetts Institute of Technology James G. Fujimoto Thorlabs
14. Ultrahigh speed endoscopic optical coherence tomography using micromotor imaging catheter and VCSEL technology
  
  Explore opticsinfobase.org Jul 15 2013 Cardiology , Gastroenterology , Probes
  
  We developed a micromotor based miniature catheter with an outer diameter of 3.2 mm for ultrahigh speed endoscopic swept source optical coherence tomography (OCT) using a vertical cavity surface-emitting laser (VCSEL) at a 1 MHz axial scan rate. The micromotor can rotate a micro-prism at several hundred frames per second with less than 5 V drive voltage to provide fast and stable scanning, which is not sensitive to the bending of the catheter. The side-viewing probe can be pulled back to acquire a three-dimensional (3D) data set covering a large area on the specimen. The VCSEL provides a high ...
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  Mentions: Massachusetts Institute of Technology James G. Fujimoto Thorlabs
15. Ultrahigh speed endoscopic optical coherence tomography using micro-motor imaging catheter and VCSEL technology
  
  Explore Conference Proceedings Apr 1 2013 Gastroenterology , Probes
  
  We developed a micro-motor based miniature catheter with an outer diameter of 3mm for ultrahigh speed endoscopic optical coherence tomography (OCT) using vertical cavity surface-emitting laser (VCSEL) at a 1MHz axial scan rate. The micro-motor can rotate a micro-prism at 1,200-72,000rpm (corresponding to 20- 1,200fps) with less than 5V driving voltage to provide fast and stable scanning, which is not sensitive to the bending of the catheter. The side-viewing probe can be pulled back for a long distance to acquire three-dimensional (3D) dataset covering a large area on the specimen. VCSEL provides high a-line rate to support ...
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  Mentions: Massachusetts Institute of Technology James G. Fujimoto Thorlabs
16. Structural markers observed with endoscopic 3-dimensional optical coherence tomography correlating with Barrett's esophagus radiofrequency ablation treatment response (with videos)
  
  Explore Gastrointestinal Endoscopy Jul 25 2012 Gastroenterology
  
  Background Radiofrequency ablation (RFA) is effective for treating Barrett's esophagus (BE) but often involves multiple endoscopy sessions over several months to achieve complete response. Objective Identify structural markers that correlate with treatment response by using 3-dimensional (3-D) optical coherence tomography (OCT; 3-D OCT). Design Cross-sectional. Setting Single teaching hospital. Patients Thirty-three patients, 32 male and 1 female, with short-segment (<3 cm) BE undergoing RFA treatment. Intervention Patients were treated with focal RFA, and 3-D OCT was performed at the gastroesophageal junction before and immediately after the RFA treatment. Patients were re-examined with standard endoscopy 6 to 8 weeks later ...
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  Mentions: Desmond C. Adler Massachusetts Institute of Technology James G. Fujimoto
17. Comparison of Tissue Architectural Changes between Radiofrequency Ablation and Cryospray Ablation in Barrett’s Esophagus Using Endoscopic Three-Dimensional Optical Coherence Tomography
  
  Explore Hindawi Publishing Corporation Jul 15 2012 Gastroenterology
  
  Two main nonsurgical endoscopic approaches for ablating dysplastic and early cancer lesions in the esophagus have gained popularity, namely, radiofrequency ablation (RFA) and cryospray ablation (CSA). We report a uniquely suited endoscopic and near-microscopic imaging modality, three-dimensional (3D) optical coherence tomography (OCT), to assess and compare the esophagus immediately after RFA and CSA. The maximum depths of architectural changes were measured and compared between the two treatment groups. RFA was observed to induce 230~260
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  Mentions: Desmond C. Adler Massachusetts Institute of Technology James G. Fujimoto
18. Cervical inlet patch-optical coherence tomography imaging and clinical significance
  
  Explore World J. Gastroenterology May 30 2012 Gastroenterology
  
  AIM: To demonstrate the feasibility of optical coherence tomography (OCT) imaging in differentiating cervical inlet patch (CIP) from normal esophagus, Barrett’s esophagus (BE), normal stomach and duodenum. METHODS: This study was conducted at the Veterans Affairs Boston Healthcare System (VABHS). Patients undergoing standard esophagogastroduodenoscopy at VABHS, including one patient with CIP, one representative patient with BE and three representative normal subjects were included. White light video endoscopy was performed and endoscopic 3D-OCT images were obtained in each patient using a prototype OCT system. The OCT imaging probe passes through the working channel of the endoscope to enable simultaneous video ...
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  Mentions: Desmond C. Adler Massachusetts Institute of Technology James G. Fujimoto
19. Characterization of buried glands before and after radiofrequency ablation by using 3-dimensional optical coherence tomography (with videos)
  
  Explore Gastrointestinal Endoscopy Apr 8 2012 Gastroenterology
  
  Background: Radiofrequency ablation (RFA) is an endoscopic technique used to eradicate Barrett's esophagus (BE). However, such ablation can commonly lead to neosquamous epithelium overlying residual BE glands not visible by conventional endoscopy and may evade detection on random biopsy samples.Objective: To demonstrate the capability of endoscopic 3-dimensional optical coherence tomography (3D-OCT) for the identification and characterization of buried glands before and after RFA therapy.Design: Cross-sectional study.Setting: Single teaching hospital.Patients: Twenty-six male and 1 female white patients with BE undergoing RFA treatment.Interventions: 3D-OCT was performed at the gastroesophageal junction in 18 patients before attaining complete ...
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  Mentions: Desmond C. Adler Massachusetts Institute of Technology James G. Fujimoto
20. Three-dimensional endoscopic optical coherence tomography imaging of cervical inlet patch
  
  Explore Gastrointestinal Endoscopy Feb 20 2012 Gastroenterology
  
  A 30-year-old white man with established Barrett's esophagus (BE) and continued symptoms of chronic severe heartburn, persistent cough, throat irritation, and asthma was referred for surveillance EGD...
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  Mentions: Desmond C. Adler Massachusetts Institute of Technology James G. Fujimoto
21. Piezoelectric-transducer-based miniature catheter for ultrahigh-speed endoscopic optical coherence tomography
  
  Explore opticsinfobase.org Jul 29 2011 Cardiology , Gastroenterology
  
  We developed a piezoelectric-transducer- (PZT) based miniature catheter with an outer diameter of 3.5 mm for ultrahigh-speed endoscopic optical coherence tomography (OCT). A miniaturized PZT bender actuates a fiber and the beam is scanned through a GRIN lens and micro-prism to provide high-speed, side-viewing capability. The probe optics can be pulled back over a long distance to acquire three-dimensional (3D) data sets covering a large area. Imaging is performed with 11 μm axial resolution in air (8 μm in tissue) and 20 μm transverse resolution, at 960 frames per second with a Fourier domain mode-locked laser operating at 480 ...
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  Mentions: Massachusetts Institute of Technology James G. Fujimoto Thorlabs
22. Piezoelectric transducer based miniature catheter for ultrahigh speed endoscopic optical coherence tomography
  
  Explore SPIE Digital Library Feb 10 2011 Gastroenterology , Probes
  
  We developed a piezoelectric transducer (PZT) based miniature catheter with an outer diameter of 3 mm for ultrahigh speed endoscopic optical coherence tomography (OCT) using Fourier domain modelocked (FDML) laser at a 480 kHz axial scan rate. The miniaturized PZT bender actuates a fiber to provide high scanning speed. The side-viewing probe can be pulled back for a long distance to acquire three-dimensional (3D) dataset covering a large area on the specimen. Operating with a high speed data acquisition (DAQ) system, OCT imaging with 6.5 mm imaging range, 10 μm axial resolution, 20 μm lateral resolution, and frame rate ...
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  Mentions: Massachusetts Institute of Technology James G. Fujimoto Benjamin M. Potsaid
23. Integrated Optical Coherence Tomography and Microscopy for Ex Vivo Multiscale Evaluation of Human Breast Tissues
  
  Explore Cancer Research Nov 6 2010 Microscopy , Oncology
  
  3D tissue imaging methods are expected to improve surgical management of cancer. In this study, we examined the feasibility of two 3D imaging technologies, optical coherence tomography (OCT) and optical coherence microscopy (OCM), to view human breast specimens based on intrinsic optical contrast. Specifically, we imaged 44 ex vivo breast specimens including 34 benign and 10 malignant lesions with an integrated OCT and OCM system developed in our laboratory. The system enabled 4 um axial resolution (OCT and OCM) with 14 um (OCT) and 2 um (OCM) transverse resolution, respectively. OCT and OCM images were compared with corresponding histologic sections ...
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  Mentions: Beth Israel Deaconess Medical Center Massachusetts Institute of Technology James G. Fujimoto
24. Features of Sub-Epithelial Glandular Structures on Three-Dimensional Endoscopic Optical Coherence Tomography (3D-EOCT) After Endoscopic Mucosal Ablation
  
  Explore Gastrointestinal Endoscopy Mar 31 2010 Gastroenterology
  
  Abstracts submitted to ASGE 2010. Endoscopic mucosal ablative therapies are becoming accepted as a treatment for Barrett's esophagus (BE) with high-grade dysplasia. Radiofrequency ablation (RFA) has been shown to be effective in achieving broad and superficial BE ablation and replacement with normal-appearing squamous epithelium. Endoscopic optical coherence tomography (EOCT) is an imaging technique that uniquely allows visualization of sub-surface structures. The new three-dimensional EOCT (3D-EOCT) provides both cross-sectional and en face images of examined structures. 3D-EOCT may represent a novel method for post-ablation BE surveillance by revealing different glandular structures underneath the post-ablative surface epithelium.
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  Mentions: Desmond C. Adler Massachusetts Institute of Technology James G. Fujimoto
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