1. Osman O. Ahsen

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    1. Mentioned In 19 Articles

    2. Feature Of The Week 10/08/2018: Clinical Utility of Ultrahigh-Speed Endoscopic Optical Coherence Tomography in Gastroenterology

      Feature Of The Week 10/08/2018: Clinical Utility of Ultrahigh-Speed Endoscopic Optical Coherence Tomography in Gastroenterology
      ...ith neoplasia and pathogenesis. For more information see recent Article1 , Article2 , and Article3 . Courtesy Osman O. Ahsen from the Massachusetts Institute of Technology . Barrett’s esophagus (BE) surveillance is limit...
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    3. Assessment of Barrett’s esophagus and dysplasia with ultrahigh-speed volumetric en face and cross-sectional optical coherence tomography

      Assessment of Barrett’s esophagus and dysplasia with ultrahigh-speed volumetric en face and cross-sectional optical coherence tomography
      Background This study aimed to evaluate the use of ultrahigh-speed volumetric en face and cross-sectional optical coherence tomography (OCT) with micromotor catheters for the in vivo assessment of Barretts esophagus and dysplasia. Methods 74 OCT datasets with correlated biopsy/endoscopic mucosal resection histology (49 nondysplastic Barretts esophagus [NDBE], 25 neoplasia) were obtained from 14 patients with Barretts esophagus and a history of dysplasia and 30 with NDBE. The associations between ...
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    4. Cycloid scanning for wide field optical coherence tomography endomicroscopy and angiography in vivo

      Cycloid scanning for wide field optical coherence tomography endomicroscopy and angiography in vivo
      Devices that perform wide field-of-view (FOV) precision optical scanning are important for endoscopic assessment and diagnosis of luminal organ disease such as in gastroenterology. Optical scanning for in vivo endoscopic imaging has traditionally relied on one or more proximal mechanical actuators, limiting scan accuracy and imaging speed. There is a need for rapid and precise two-dimensional (2D) microscanning technologies to enable the translation of benchtop scanning microscopies to in vivo ...
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    5. Ultrahigh-speed endoscopic optical coherence tomography and angiography enables delineation of lateral margins of endoscopic mucosal resection: a case report

      Ultrahigh-speed endoscopic optical coherence tomography and angiography enables delineation of lateral margins of endoscopic mucosal resection: a case report
      Endoscopic mucosal resection (EMR) is a common technique for resecting dysplastic lesions in Barretts esophagus (BE), stomach, and colon, 1 but precise delineation of dysplastic margins before resection and verification of complete removal after resection remain challenging. 2 , 3 Endoscopic optical coherence tomography (OCT) enables three-dimensional visualization of tissue microstructure and is commercially available as Volumetric Laser Endomicroscopy (NinePoint Medical, Bedford, MA, USA). 4 , 5 We recently developed an ultrahigh-speed ...
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    6. Endoscopic forward-viewing optical coherence tomography and angiography with MHz swept source

      Endoscopic forward-viewing optical coherence tomography and angiography with MHz swept source
      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 m field of view and 5 m transverse resolution, imaging at 1 MHz axial scan rate in the human gastrointestinal tract. The probe ...
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    7. Assessment of the radiofrequency ablation dynamics of esophageal tissue with optical coherence tomography

      Assessment of the radiofrequency ablation dynamics of esophageal tissue with optical coherence tomography
      Radiofrequency ablation (RFA) is widely used for the eradication of dysplasia and the treatment of early stage esophageal carcinoma in patients with Barretts 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 ...
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    8. Endoscopic optical coherence tomography angiography microvascular features associated with dysplasia in Barrett's esophagus: a pilot study (with video)

      Endoscopic optical coherence tomography angiography microvascular features associated with dysplasia in Barrett's esophagus: a pilot study (with video)
      Background and Aims Angiogenesis is associated with neoplastic progression of Barretts esophagus (BE). Volumetric optical coherence tomography angiography (OCTA) visualizes subsurface microvasculature without exogenous contrast agents. We investigated the association of OCTA microvascular features with low-grade dysplasia (LGD) and high-grade dysplasia (HGD). Methods Fifty-two patients undergoing BE surveillance or endoscopic eradication therapies for dysplasia were imaged using volumetric OCTA and corresponding histological diagnoses obtained, to yield 97 data sets (non-dysplastic ...
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    9. Volumetric Mapping of Barrett’s Esophagus and Dysplasia With en face Optical Coherence Tomography Tethered Capsule

      Volumetric Mapping of Barrett’s Esophagus and Dysplasia With en face Optical Coherence Tomography Tethered Capsule
      To the Editor: Dysplasia in Barretts Esophagus (BE) is patchy ( 1 ) and sometimes missed by random biopsies. Optical coherence tomography (OCT) can image large areas of the esophagus; however, slow imaging speeds in earlier studies limited visualization to cross-sections. Cross-sectional OCT detected high-grade dysplasia with sensitivity / specificity of ~80 % ( 2 , 3 ). Tethered OCT capsules were demonstrated for cross-sectional imaging in unsedated screening to detect BE ( 4 , 5 ). Our group recently ...
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    10. Feature Of The Week 03/08/2015: Endoscopic Optical Coherence Angiography Enables Three Dimensional Visualization of Subsurface Microvasculature

      Feature Of The Week 03/08/2015: Endoscopic Optical Coherence Angiography Enables Three Dimensional Visualization of Subsurface Microvasculature
      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 ...
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    11. Ultrahigh speed endoscopic optical coherence tomography for gastroenterology

      Ultrahigh speed endoscopic optical coherence tomography for 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 m axial resolution in tissue. Imaging was performed with a 3.2 mm diameter imaging catheter at 400 frames per second with a 12 m spot size. Three-dimensional OCT (3D-OCT) imaging was performed ...
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    12. Ultrahigh speed endoscopic swept source optical coherence tomography using a VCSEL light source and micromotor catheter

      Ultrahigh speed endoscopic swept source optical coherence tomography using a VCSEL light source and micromotor catheter
      ...wept source optical coherence tomography using a VCSEL light source and micromotor catheter Tsung-Han Tsai ; Osman O. Ahsen ; Hsiang-Chieh Lee ; Kaicheng Liang ; Michael G. Giacomelli ; Benjamin M. Potsaid ; Yuankai K. ...
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    13. 1-15 of 19 1 2 »
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  2. About Osman O. Ahsen

    Osman O. Ahsen

    Osman O. Ahsen has done his Master’s and Doctoral thesis research in the Biomedical Optical Imaging and Biophotonics Group at the Massachusetts Institute of Technology with supervision from Dr. James G. Fujimoto. He has worked on development of a prototype ultrahigh speed endoscopic swept-source OCT system with micromotor-based catheters and its clinical translation to the VA Boston Healthcare System (VABHS). The combination of high speed imaging and precise distal beam scanning allowed visualization of depth-resolved en face mucosal and microvascular patterns (OCT angiography), in addition to standard cross-sectional imaging, enabling new clinical applications of endoscopic OCT. Osman is currently working as a postdoctoral research fellow at the Wellman Center for Photomedicine with supervision from Dr. Guillermo J. Tearney. His current research interest is on developing novel imaging techniques for coronary artery disease.