1. Articles from Zhao Wang

    1-24 of 44 1 2 »
    1. Application and Evaluation of Highly Automated Software for Comprehensive Stent Analysis in Intravascular Optical Coherence Tomography

      Application and Evaluation of Highly Automated Software for Comprehensive Stent Analysis in Intravascular Optical Coherence Tomography

      Intravascular optical coherence tomography (IVOCT) is used to assess stent tissue coverage and malapposition in stent evaluation trials. We developed the OCT Image Visualization and Analysis Toolkit for Stent (OCTivat-Stent), for highly automated analysis of IVOCT pullbacks. Algorithms automatically detected the guidewire, lumen boundary, and stent struts; determined the presence of tissue coverage for each strut; and estimated the stent contour for comparison of stent and lumen area. Strut-level tissue thickness, tissue coverage area, and malapposition area were automatically quantified. The software was used to analyze 292 stent pullbacks. The concordance-correlation-coefficients of automatically measured stent and lumen areas and independent ...

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    2. Analysis of optical tomography (OCT) images

      Analysis of optical tomography (OCT) images

      A method includes storing three-dimensional image data acquired intravascularly via an optical coherence tomography (OCT) apparatus. The image data is analyzed to compute a probability estimate of stent presence at support positions appearing in an A-line. Stent strut locations are located in three-dimensional space based on the computed probability estimate of stent presence.

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    3. Computer-Aided Analysis of Gland-Like Subsurface Hyposcattering Structures in Barrett’s Esophagus Using Optical Coherence Tomography

      Computer-Aided Analysis of Gland-Like Subsurface Hyposcattering Structures in Barrett’s Esophagus Using Optical Coherence Tomography

      (1) Background: Barrett’s esophagus (BE) is a complication of chronic gastroesophageal reflux disease and is a precursor to esophageal adenocarcinoma. The clinical implication of subsurface glandular structures of Barrett’s esophagus is not well understood. Optical coherence tomography (OCT), also known as volumetric laser endomicroscopy (VLE), can assess subsurface glandular structures, which appear as subsurface hyposcattering structures (SHSs). The aim of this study is to develop a computer-aided algorithm and apply it to investigate the characteristics of SHSs in BE using clinical VLE data; (2) Methods: SHSs were identified with an initial detection followed by machine learning. Comprehensive SHS ...

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    4. 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

      Barrett’s esophagus (BE) surveillance is limited by biopsy sampling error. Optical coherence tomography (OCT) enables microscopic resolution, high speed, volumetric imaging and is commercially available as volumetric laser endomicroscopy (VLE, NinePoint Medical). Studies investigated cross-sectional OCT dysplasia features, including a diagnostic algorithm (VLE-DA), however, many VLE studies used ex vivo specimens due to challenges in registering biopsy with OCT. We previously demonstrated ultrahigh-speed endoscopic OCT >10x faster than commercial instruments, enabling depth-resolved en face and cross-sectional imaging. This study investigated volumetric en face and cross-sectional OCT for identifying neoplasia. 74 OCT datasets with correlated biopsy/endoscopic mucosal resection histology ...

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    5. 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 Barrett’s esophagus and dysplasia. Methods  74 OCT datasets with correlated biopsy/endoscopic mucosal resection histology (49 nondysplastic Barrett’s esophagus [NDBE], 25 neoplasia) were obtained from 14 patients with Barrett’s esophagus and a history of dysplasia and 30 with NDBE. The associations between irregular mucosal patterns on en face OCT, absence of mucosal layering, surface signal > subsurface, and > 5 atypical glands on cross-sectional OCT vs. histology and treatment history were ...

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    6. 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 endoscopic imaging. We demonstrate a new cycloid scanner in a tethered capsule for ultrahigh speed, side-viewing optical coherence tomography (OCT) endomicroscopy in vivo . The cycloid capsule incorporates two scanners: a ...

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    7. 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 Barrett’s 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 endoscopic OCT system which operates more than 10 times faster than commercial instruments, generating volumetric images with higher transverse resolution and voxel density. 6 , 7 This allows visualization of ...

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    8. Clinical Predictors for Lack of Favorable Vascular Response to Statin Therapy in Patients With Coronary Artery Disease: A Serial Optical Coherence Tomography Study

      Clinical Predictors for Lack of Favorable Vascular Response to Statin Therapy in Patients With Coronary Artery Disease: A Serial Optical Coherence Tomography Study

      Background Previous studies have demonstrated that statin therapy improves cardiac outcomes, probably by stabilizing thin‐cap fibroatheroma in patients with coronary artery disease. However, major adverse cardiac events still occur in some patients, despite statin therapy. The aim of this study is to identify clinical predictors for the lack of a favorable vascular response to statin therapy in patients with coronary artery disease. Methods and Results A total of 140 nonculprit plaques from 84 patients with coronary artery disease who were treated with a statin and had serial optical coherence tomography imaging (median interval, 6.3 months) were included. Thin ...

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    9. 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 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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    10. Dynamic neointimal pattern after drug-eluting stent implantation defined by optical coherence tomography

      Dynamic neointimal pattern after drug-eluting stent implantation defined by optical coherence tomography

      Objectives: Certain neointimal patterns including neoatherosclerosis (NA) are known to be associated with poor clinical outcome. The prevalence and time course of different neointimal patterns have not been studied systematically. The aim of this study was to investigate the serial changes in neointimal pattern after drug-eluting stent implantation. Patients and methods: A total of 132 patients with 207 drug-eluting stents, who underwent two follow-up optical coherence tomography studies at 6 and 12 months, were included. Neointimal patterns were categorized as homogeneous, heterogeneous, layered, or NA using optical coherence tomography. Quantitative and qualitative analyses of neointima were carried out. Results: Both ...

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    11. Clinical Significance of Lipid-Rich Plaque Detected by Optical Coherence Tomography : A 4-Year Follow-Up Study

      Clinical Significance of Lipid-Rich Plaque Detected by Optical Coherence Tomography : A 4-Year Follow-Up Study

      Background Lipid-rich plaque (LRP) is thought to be a precursor to cardiac events. However, its clinical significance in coronary arteries has never been systematically investigated. Objectives This study investigated the prevalence and clinical significance of LRP in the nonculprit region of the target vessel in patients undergoing percutaneous coronary intervention (PCI). Methods The study included 1,474 patients from 20 sites across 6 countries undergoing PCI, who had optical coherence tomography (OCT) imaging of the target vessel. Major adverse cardiac events (MACE) were defined as a composite of cardiac death, acute myocardial infarction, and ischemia-driven revascularization. Patients were followed for ...

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    12. Management and Outcome of Patients With Acute Coronary Syndrome Caused by Plaque Rupture Versus Plaque Erosion: An Intravascular Optical Coherence Tomography Study

      Management and Outcome of Patients With Acute Coronary Syndrome Caused by Plaque Rupture Versus Plaque Erosion: An Intravascular Optical Coherence Tomography Study

      Background Plaque rupture and erosion are the 2 most common mechanisms for acute coronary syndromes. However, the outcome of these 2 distinct pathologies in patients with acute coronary syndromes has never been studied. Methods and Results We retrospectively studied 141 patients with acute coronary syndromes who underwent optical coherence tomography ( OCT ) imaging of the culprit lesion prior to stenting from the Massachusetts General Hospital OCT Registry. Management (stent versus no stent), poststent OCT findings, and outcomes were compared. Among the 141 culprit lesions, rupture was found in 79 (56%) patients and erosion in 62 (44%). Stent implantation was performed in ...

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    13. 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 Barrett’s 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 BE (NDBE): N=74; LGD: N=10; HGD: N=13). After evaluating OCTA image quality, 54 datasets (NDBE: N=35; LGD: N=8; HGD: N=11) from 32 patients ...

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    14. Cubic meter volume optical coherence tomography

      Cubic meter volume optical coherence tomography

      Optical coherence tomography (OCT) is a powerful three-dimensional (3D) imaging modality with micrometer-scale axial resolution and up to multi-GigaVoxel/s imaging speed. However, the imaging range of high-speed OCT has been limited. Here, we report 3D OCT over cubic meter volumes using a long coherence length, 1310 nm vertical-cavity surface-emitting laser and silicon photonic integrated circuit dual-quadrature receiver technology combined with enhanced signal processing. We achieved 15 μm depth resolution for tomographic imaging at a 100 kHz axial scan rate over a 1.5 m range. We show 3D macroscopic imaging examples of a human mannequin, bicycle, machine shop gauge ...

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    15. 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 Barrett’s 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 developed ultrahigh-speed OCT for en face and angiographic imaging, using micromotor probes in patients ( 6 , 7 ) and large field-of-view tethered capsule devices in swine ( 8 ). Narrow-band imaging (NBI) visualizes ...

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    16. Laser eye surgery system

      Laser eye surgery system

      A laser eye surgery system includes a laser source, a ranging subsystem, an integrated optical subsystem, and a patient interface assembly. The laser source produces a treatment beam that includes a plurality of laser pulses. The ranging subsystem produces a source beam used to locate one or more structures of an eye. The ranging subsystem includes an optical coherence tomography (OCT) pickoff assembly that includes a first optical wedge and a second optical wedge separated from the first optical wedge. The OCT pickoff assembly is configured to divide an OCT source beam into a sample beam and a reference beam ...

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      Mentions: Abbot
    17. Circumferential optical coherence tomography angiography imaging of the swine esophagus using a micromotor balloon catheter

      Circumferential optical coherence tomography angiography imaging of the swine esophagus using a micromotor balloon catheter

      We demonstrate a micromotor balloon imaging catheter for ultrahigh speed endoscopic optical coherence tomography (OCT) which provides wide area, circumferential structural and angiographic imaging of the esophagus without contrast agents. Using a 1310 nm MEMS tunable wavelength swept VCSEL light source, the system has a 1.2 MHz A-scan rate and ~8.5 µm axial resolution in tissue. The micromotor balloon catheter enables circumferential imaging of the esophagus at 240 frames per second (fps) with a ~30 µm (FWHM) spot size. Volumetric imaging is achieved by proximal pullback of the micromotor assembly within the balloon at 1.5 mm/sec ...

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    18. Three-dimensional morphological response of lipid-rich coronary plaques to statin therapy: a serial optical coherence tomography study

      Three-dimensional morphological response of lipid-rich coronary plaques to statin therapy: a serial optical coherence tomography study

      Objective: Previous studies have suggested that intensive statin therapy, compared with moderate statin therapy, provided greater reduction of LDL and better protection against major cardiovascular events. However, the exact dose-dependent mechanism of plaque stabilization remains unclear. The aim of this study is to investigate the three-dimensional (3D) response of fibrous caps overlying lipid plaques to statin therapy. Methods: We applied a novel computer algorithm to investigate the fibrous cap 3D morphological change over time in patients with coronary artery disease. Patients were treated with either atorvastatin 20 mg/day (moderate intensity) or atorvastatin 60 mg/day (high intensity). Optical coherence ...

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    19. Coronary Calcification and Plaque Vulnerability An Optical Coherence Tomographic Study

      Coronary Calcification and Plaque Vulnerability An Optical Coherence Tomographic Study

      Background— Spotty superficial calcium deposits have been implicated in plaque vulnerability based on previous intravascular imaging studies. Biomechanical models suggest that microcalcifications between 5 and 65 µm in diameter can intensify fibrous cap stress, promoting plaque rupture. However, the 100- to 200-µm resolution of intravascular ultrasound limits its ability to discriminate single calcium deposits from clusters of smaller deposits, and a previous optical coherence tomographic investigation evaluated calcifications within a long segment of artery, which may not truly reflect the mechanics involved in potentiating focal plaque rupture. Methods and Results— Detailed optical coherence tomographic assessment of coronary calcification at ...

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    20. Quantitative analysis of the side-branch orifice after bifurcation stenting using en-face processing of OCT images: a comparison between Xience V and Resolute Integrity stents

      Quantitative analysis of the side-branch orifice after bifurcation stenting using en-face processing of OCT images: a comparison between Xience V and Resolute Integrity stents

      Objective: Methods for intravascular assessment of the side-branch (SB) orifice after stenting are not readily available. The aim of this study was to assess the utility of an en-face projection processing for optical coherence tomography (OCT) images for SB evaluation. Methods: Measurements of the SB orifice obtained using en-face OCT images were validated using a phantom model. Linear regression modeling was applied to estimated area measurements made on the en-face images. The SB orifice was then analyzed in 88 patients with bifurcation lesions treated with either Xience V (everolimus-eluting stent) or Resolute Integrity [zotarolimus-eluting stent (ZES)]. The SB orifice area ...

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    21. Silicon photonic integrated circuit swept-source optical coherence tomography receiver with dual polarization, dual balanced, in-phase and quadrature detection

      Silicon photonic integrated circuit swept-source optical coherence tomography receiver with dual polarization, dual balanced, in-phase and quadrature detection

      Optical coherence tomography (OCT) is a widely used three-dimensional (3D) optical imaging method with many biomedical and non-medical applications. Miniaturization, cost reduction, and increased functionality of OCT systems will be critical for future emerging clinical applications. We present a silicon photonic integrated circuit swept-source OCT (SS-OCT) coherent receiver with dual polarization, dual balanced, in-phase and quadrature (IQ) detection. We demonstrate multiple functional capabilities of IQ polarization resolved detection including: complex-conjugate suppressed full-range OCT, polarization diversity detection, and polarization-sensitive OCT. To our knowledge, this is the first demonstration of a silicon photonic integrated receiver for OCT. The integrated coherent receiver provides ...

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    22. Impacts of lesion angle on incidence and distribution of acute vessel wall injuries and strut malapposition after drug-eluting stent implantation assessed by optical coherence tomography

      Impacts of lesion angle on incidence and distribution of acute vessel wall injuries and strut malapposition after drug-eluting stent implantation assessed by optical coherence tomography

      Aims To investigate the impact of lesion angle on the incidence and distribution of acute vessel wall injuries and incomplete stent apposition (ISA) following second-generation drug-eluting stent (DES) implantation using optical coherence tomography (OCT). Several ex vivo studies demonstrated that angled arterial walls are exposed to imbalanced mechanical stress from deployed stents. Methods and results We included 243 lesions treated with a single DES (148 everolimus-eluting stent and 95 zotarolimus-eluting stent). Angled lesions were defined as lesions with angle ≥45° on an angiogram ( n = 58). The vessel wall injuries and ISA were evaluated by OCT. The results were compared with ...

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    23. 3-D Stent Detection in Intravascular OCT Using a Bayesian Network and Graph Search

      3-D Stent Detection in Intravascular OCT Using a Bayesian Network and Graph Search

      Worldwide, many hundreds of thousands of stents are implanted each year to revascularize occlusions in coronary arteries. Intravascular optical coherence tomography (OCT) is an important emerging imaging technique, which has the resolution and contrast necessary to quantitatively analyze stent deployment and tissue coverage following stent implantation. Automation is needed, as current, it takes up to 16 hours to manually analyze hundreds of images and thousands of stent struts from a single pullback. For automated strut detection, we used image formation physics and machine learning via a Bayesian network, and 3-D knowledge of stent structure via graph search. Graph search was ...

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    24. Ultrahigh speed en face OCT capsule for endoscopic imaging

      Ultrahigh speed en face OCT capsule for endoscopic imaging

      Depth resolved and en face OCT visualization in vivo may have important clinical applications in endoscopy. We demonstrate a high speed, two-dimensional (2D) distal scanning capsule with a micromotor for fast rotary scanning and a pneumatic actuator for precision longitudinal scanning. Longitudinal position measurement and image registration were performed by optical tracking of the pneumatic scanner. The 2D scanning device enables high resolution imaging over a small field of view and is suitable for OCT as well as other scanning microscopies. Large field of view imaging for screening or surveillance applications can also be achieved by proximally pulling back or ...

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    1-24 of 44 1 2 »
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    1. (41 articles) Zhao Wang
    2. (23 articles) Massachusetts Institute of Technology
    3. (20 articles) James G. Fujimoto
    4. (16 articles) Case Western Reserve University
    5. (15 articles) Harvard University
    6. (14 articles) Hsiang-Chieh Lee
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    Semiautomatic segmentation and quantification of calcified plaques in intracoronary optical coherence tomography images Plaque and thrombus evaluation by optical coherence tomography Optical Coherence Tomography and Fibrous Cap Characterization Congratulations to Zhao Wang from CWRU a Winner of a 2012 Student Travel Grant Award Intravascular Optical Coherence Tomography Detection of Atherosclerosis and Inflammation in Murine Aorta Three-Dimensional Fourier-Domain Optical Coherence Tomography Imaging: Advantages and Future Development Automatic stent detection in intravascular OCT images using bagged decision trees Feature Of The Week 1/20/13: CWRU Demonstrates Automatic Stent Detection in Intravascular OCT Images Using Bagged Decision Trees Endoscopic optical coherence tomography angiography microvascular features associated with dysplasia in Barrett's esophagus: a pilot study (with video) Artifact Rates for 2D Retinal Nerve Fiber Layer Thickness Versus 3D Neuroretinal Rim Thickness Using Spectral-Domain Optical Coherence Tomography Development of Deep Learning Models to Predict Best-Corrected Visual Acuity from Optical Coherence Tomography Machine learning helps improve diagnostic ability of subclinical keratoconus using Scheimpflug and OCT imaging modalities