1. Articles from jonathan j. liu

    1-24 of 33 1 2 »
    1. 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 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 ...

      Read Full Article
    2. Three Dimensional Enhanced Imaging of Vitreoretinal Interface in Diabetic Retinopathy Using Swept Source Optical Coherence Tomography

      Three Dimensional Enhanced Imaging of Vitreoretinal Interface in Diabetic Retinopathy Using Swept Source Optical Coherence Tomography

      Purpose To analyze the vitreoretinal interface in diabetic eyes using three-dimensional wide-field volumes acquired using high-speed, long-wavelength swept-source optical coherence tomography (SS-OCT). Design Prospective cross-sectional study. Methods Fifty-six diabetic patients (88 eyes) and 11 healthy non-diabetic controls (22 eyes) were recruited. Up to eight SS-OCT volumes were acquired for each eye. A registration algorithm removed motion artifacts and merged multiple SS-OCT volumes to improve signal. Vitreous visualization was enhanced using vitreous windowing method. Results Of 88 diabetic eyes, 20 eyes had no retinopathy, 21 eyes had non-proliferative diabetic retinopathy (NPDR) without macular edema, 20 eyes had proliferative diabetic retinopathy (PDR ...

      Read Full Article
    3. High-Speed Ultrahigh-Resolution OCT of Bruch's Membrane in Membranoproliferative Glomerulonephritis Type 2

      High-Speed Ultrahigh-Resolution OCT of Bruch's Membrane in Membranoproliferative Glomerulonephritis Type 2

      Membranoproliferative glomerulonephritis (MPGN) type 2 is characterized by electron-dense deposits in the glomerular basement membrane and drusen-like deposits in Bruch's membrane. Over time, atrophic changes in the retina and retinal pigment epithelium occur, which can progress to choroidal neovascularization (CNV). This report describes a patient with MPGN type 2 who developed progressive loss of vision secondary to CNV. High-speed ultrahigh-resolution optical coherence tomography (UHR-OCT) showed an irregular Bruch's membrane that measured 10 μm beneath the foveal center. High-speed UHR-OCT can potentially be used to analyze Bruch's membrane in secondary ocular manifestations of diseases such as MPGN type ...

      Read Full Article
    4. Spectral-Domain and Swept-Source OCT Imaging of Asteroid Hyalosis: A Case Report

      Spectral-Domain and Swept-Source OCT Imaging of Asteroid Hyalosis: A Case Report

      A 72-year-old man with diabetes was referred to the retina clinic for diabetic retinopathy. Detailed funduscopic examination of the left eye was limited by prominent asteroid hyalosis. Spectral-domain (SD) and swept-source (SS) optical coherence tomography (OCT) were utilized to examine the vitreous, vitreoretinal interface, and the morphology of the retina. Asteroid hyalosis induced artifacts of the OCT images, which resolved when the appropriate imaging protocols were applied. SS-OCT may show superior diagnostic and preoperative capabilities when compared to SD-OCT in the settings of asteroid hyalosis-induced media opacity.

      Read Full Article
    5. Enhanced Vitreous Imaging in Healthy Eyes Using Swept Source Optical Coherence Tomography

      Enhanced Vitreous Imaging in Healthy Eyes Using Swept Source Optical Coherence Tomography

      Purpose To describe enhanced vitreous imaging for visualization of anatomic features and microstructures within the posterior vitreous and vitreoretinal interface in healthy eyes using swept-source optical coherence tomography (SS-OCT). The study hypothesis was that long-wavelength, high-speed, volumetric SS-OCT with software registration motion correction and vitreous window display or high-dynamic-range (HDR) display improves detection sensitivity of posterior vitreous and vitreoretinal features compared to standard OCT logarithmic scale display. Design Observational prospective cross-sectional study. Methods Multiple wide-field three-dimensional SS-OCT scans (500×500A-scans over 12×12 mm 2 ) were obtained using a prototype instrument in 22 eyes of 22 healthy volunteers. A registration ...

      Read Full Article
    6. Optical coherence tomography angiography of optic nerve head and parafovea in multiple sclerosis

      Optical coherence tomography angiography of optic nerve head and parafovea in multiple sclerosis

      Aims To investigate swept-source optical coherence tomography (OCT) angiography in the optic nerve head (ONH) and parafoveal regions in patients with multiple sclerosis (MS). Methods Fifty-two MS eyes and 21 healthy control (HC) eyes were included. There were two MS subgroups: 38 MS eyes without an optic neuritis (ON) history (MS −ON), and 14 MS eyes with an ON history (MS +ON). The OCT images were captured by high-speed 1050 nm swept-source OCT. The ONH flow index (FI) and parafoveal FI were quantified from OCT angiograms. Results The mean ONH FI was 0.160±0.010 for the HC group ...

      Read Full Article
    7. Reproducibility of In-Vivo OCT Measured Three-Dimensional Human Lamina Cribrosa Microarchitecture

      Reproducibility of In-Vivo OCT Measured Three-Dimensional Human Lamina Cribrosa Microarchitecture

      Purpose To determine the reproducibility of automated segmentation of the three-dimensional (3D) lamina cribrosa (LC) microarchitecture scanned in-vivo using optical coherence tomography (OCT). Methods Thirty-nine eyes (8 healthy, 19 glaucoma suspects and 12 glaucoma) from 49 subjects were scanned twice using swept-source (SS−) OCT in a 3.5×3.5×3.64 mm (400×400×896 pixels) volume centered on the optic nerve head, with the focus readjusted after each scan. The LC was automatically segmented and analyzed for microarchitectural parameters, including pore diameter, pore diameter standard deviation (SD), pore aspect ratio, pore area, beam thickness, beam thickness SD, and ...

      Read Full Article
    8. Feature Of The Week 4/2/14: A Compact High-Performance Hand-Held Device for Extending Ophthalmic OCT to New Points of Care (Narrated Presentation)

      Feature Of The Week 4/2/14: A Compact High-Performance Hand-Held Device for Extending Ophthalmic OCT to New Points of Care (Narrated Presentation)

      We developed an ultrahigh speed, handheld swept source optical coherence tomography (SS-OCT) ophthalmic instrument using a 2D MEMS mirror. A vertical cavity surface-emitting laser (VCSEL) operating at 1060 nm center wavelength yielded a 350 kHz axial scan rate and 10 µm axial resolution in tissue. The long coherence length of the VCSEL enabled a 3.08 mm imaging range with minimal sensitivity roll-off in tissue. Two different designs with identical optical components were tested to evaluate handheld OCT ergonomics. An iris camera aided in alignment of the OCT beam through the pupil and a manual fixation light selected the imaging ...

      Read Full Article
    9. Quantitative Optical Coherence Tomography Angiography of Choroidal Neovascularization in Age-related Macular Degeneration

      Quantitative Optical Coherence Tomography Angiography of Choroidal Neovascularization in Age-related Macular Degeneration

      Purpose To detect and quantify choroidal neovascularization (CNV) in patients with age-related macular degeneration (AMD) using optical coherence tomography (OCT) angiography. Design Observational, cross-sectional study. Participants A total of 5 normal subjects and 5 subjects with neovascular AMD were included. Methods A total of 5 eyes with neovascular AMD and 5 normal age-matched controls were scanned by a high-speed (100 000 A-scans/seconds) 1050-nm wavelength swept-source OCT. The macular angiography scan covered a 3×3-mm area and comprised 200×200×8 A-scans acquired in 3.5 seconds. Flow was detected using the split-spectrum amplitude-decorrelation angiography (SSADA) algorithm. Motion artifacts were ...

      Read Full Article
    10. Feature Of The Week 2/16/14: En Face Enhanced-Depth Swept-Source Optical Coherence Tomography Features of Chronic Central Serous Chorioretinopath

      Feature Of The Week 2/16/14: En Face Enhanced-Depth Swept-Source Optical Coherence Tomography Features of Chronic Central Serous Chorioretinopath

      We characterized en face features of the retinal pigment epithelium (RPE) and choroid in eyes with chronic central serous chorioretinopathy (CSCR) using a high-speed, enhanced tissue penetration, swept-source optical coherence tomography (SS-OCT) prototype. Fifteen eyes of 13 consecutive patients with the clinical diagnosis of CSCR were prospectively examined with SS-OCT. Three-dimensional 6x6mm macular cube raster scans were obtained with SS-OCT operating at 1050nm wavelength and 100,000 A-lines/sec with 6µm axial resolution. Segmentation of the RPE generated a reference surface; en face SS-OCT images of the RPE and choroid were extracted at varying depths every 3.5 µm ...

      Read Full Article
    11. Handheld ultrahigh speed swept source optical coherence tomography instrument using a MEMS scanning mirror

      Handheld ultrahigh speed swept source optical coherence tomography instrument using a MEMS scanning mirror

      We developed an ultrahigh speed, handheld swept source optical coherence tomography (SS-OCT) ophthalmic instrument using a 2D MEMS mirror. A vertical cavity surface-emitting laser (VCSEL) operating at 1060 nm center wavelength yielded a 350 kHz axial scan rate and 10 µm axial resolution in tissue. The long coherence length of the VCSEL enabled a 3.08 mm imaging range with minimal sensitivity roll-off in tissue. Two different designs with identical optical components were tested to evaluate handheld OCT ergonomics. An iris camera aided in alignment of the OCT beam through the pupil and a manual fixation light selected the imaging ...

      Read Full Article
    12. In Vivo Lamina Cribrosa Micro-Architecture in Healthy and Glaucomatous Eyes as Assessed by Optical Coherence Tomography

      In Vivo Lamina Cribrosa Micro-Architecture in Healthy and Glaucomatous Eyes as Assessed by Optical Coherence Tomography

      Purpose. The lamina cribrosa (LC) is a prime location of glaucomatous damage. The purpose of this study was to compare LC 3-dimensional micro-architecture between healthy and glaucomatous eyes in vivo by using optical coherence tomography (OCT). Methods. Sixty-eight eyes (19 healthy and 49 glaucomatous) from 47 subjects were scanned in a 3.5 × 3.5 × 3.64-mm volume (400 × 400 × 896 pixels) at the optic nerve head by using swept-source OCT. The LC micro-architecture parameters were measured on the visible LC by an automated segmentation algorithm. The LC parameters were compared to diagnosis and visual field mean deviation (VF MD ...

      Read Full Article
    13. Choriocapillaris and Choroidal Microvasculature Imaging with Ultrahigh Speed OCT Angiography

      Choriocapillaris and Choroidal Microvasculature Imaging with Ultrahigh Speed OCT Angiography

      We demonstrate in vivo choriocapillaris and choroidal microvasculature imaging in normal human subjects using optical coherence tomography (OCT). An ultrahigh speed swept source OCT prototype at 1060 nm wavelengths with a 400 kHz A-scan rate is developed for three-dimensional ultrahigh speed imaging of the posterior eye. OCT angiography is used to image three-dimensional vascular structure without the need for exogenous fluorophores by detecting erythrocyte motion contrast between OCT intensity cross-sectional images acquired rapidly and repeatedly from the same location on the retina. En face OCT angiograms of the choriocapillaris and choroidal vasculature are visualized by acquiring cross-sectional OCT angiograms volumetrically ...

      Read Full Article
    14. Parafoveal Retinal Vascular Response to Pattern Visual Stimulation Assessed with OCT Angiography

      Parafoveal Retinal Vascular Response to Pattern Visual Stimulation Assessed with OCT Angiography

      We used optical coherence tomography (OCT) angiography with a high-speed swept-source OCT system to investigate retinal blood flow changes induced by visual stimulation with a reversing checkerboard pattern. The split-spectrum amplitude-decorrelation angiography (SSADA) algorithm was used to quantify blood flow as measured with parafoveal flow index (PFI), which is proportional to the density of blood vessels and the velocity of blood flow in the parafoveal region of the macula. PFI measurements were taken in 15 second intervals during a 4 minute period consisting of 1 minute of baseline, 2 minutes with an 8 Hz reversing checkerboard pattern stimulation, and 1 ...

      Read Full Article
    15. Enhanced Visualization of the Choroido-Scleral Interface Using Swept-Source OCT

      Enhanced Visualization of the Choroido-Scleral Interface Using Swept-Source OCT

      An accurate analysis of the thickness and volume of choroid using optical coherence tomography (OCT) requires precise visualization of the choroido-scleral interface. Results of studies that use spectral-domain OCT (SD-OCT) to look at the percent visualization of the choroido-scleral interface for accurate analysis of choroidal thickness show varying success rates. This study assessed the visualization of choroido-scleral interface in 19 healthy participants (19 eyes) prospectively recruited for consecutive high-definition raster scanning with an SD-OCT system with and without enhanced depth imaging (EDI) and a prototype long-wavelength swept-source OCT (SS-OCT) system. Choroido-scleral interface was visualized in all eyes imaged on SS-OCT ...

      Read Full Article
    16. En Face Enhanced-Depth Swept-Source Optical Coherence Tomography Features of Chronic Central Serous Chorioretinopathy

      En Face Enhanced-Depth Swept-Source Optical Coherence Tomography Features of Chronic Central Serous Chorioretinopathy

      Objective To characterize en face features of the retinal pigment epithelium (RPE) and choroid in eyes with chronic central serous chorioretinopathy (CSCR) using a high-speed, enhanced-depth swept-source optical coherence tomography (SS-OCT) prototype. Design Consecutive patients with chronic CSCR were prospectively examined with SS-OCT. Participants Fifteen eyes of 13 patients. Methods Three-dimensional 6×6 mm macular cube raster scans were obtained with SS-OCT operating at 1050 nm wavelength and 100 000 A-lines/sec with 6 μm axial resolution. Segmentation of the RPE generated a reference surface; en face SS-OCT images of the RPE and choroid were extracted at varying depths every ...

      Read Full Article
    17. Automated lamina cribrosa microstructural segmentation in optical coherence tomography scans of healthy and glaucomatous eyes

      Automated lamina cribrosa microstructural segmentation in optical coherence tomography scans of healthy and glaucomatous eyes

      We demonstrate an automated segmentation method for in-vivo 3D optical coherence tomography (OCT) imaging of the lamina cribrosa (LC). Manual segmentations of coronal slices of the LC were used as a gold standard in parameter selection and evaluation of the automated technique. The method was validated using two prototype OCT devices; each had a subject cohort including both healthy and glaucomatous eyes. Automated segmentation of in-vivo 3D LC OCT microstructure performed comparably to manual segmentation and is useful for investigative research and in clinical quantification of the LC.

      Read Full Article
    18. Silencing Of The Drosophila Ortholog Of SOX5 In Heart Leads To Cardiac Dysfunction As Detected By Optical Coherence Tomography

      Silencing Of The Drosophila Ortholog Of SOX5 In Heart Leads To Cardiac Dysfunction As Detected By Optical Coherence Tomography

      The SRY-related HMG-box 5 (SOX5) gene encodes a member of the SOX family of transcription factors. Recently, genome-wide association studies have implicated SOX5 as a candidate gene for susceptibility to four cardiac-related endophenotypes: higher resting heart rate (RHR), the electrocardiographic PR interval, atrial fibrillation (AF) and left ventricular mass (LVM). We have determined that human SOX5 has a highly conserved Drosophila ortholog, Sox102F, and have employed transgenic Drosophila models to quantitatively measure cardiac function in adult flies. For this purpose, we have developed a high-speed and ultrahigh-resolution optical coherence tomography (OCT) imaging system, which enables rapid cross-sectional imaging of the ...

      Read Full Article
    19. Analysis of Choroidal Morphologic Features and Vasculature in Healthy Eyes Using Spectral-Domain Optical Coherence Tomography

      Analysis of Choroidal Morphologic Features and Vasculature in Healthy Eyes Using Spectral-Domain Optical Coherence Tomography

      Objective: To analyze the morphologic features and vasculature of the choroid in healthy eyes using spectral-domain (SD) optical coherence tomography (OCT).Design: Cross-sectional retrospective review.Participants: Forty-two healthy subjects (42 eyes) with no ocular disease who underwent high-definition scanning with Cirrus high-definition OCT (Carl Zeiss Meditec, Inc., Dublin, CA) at the New England Eye Center, Boston, Massachusetts, between November 2009 and September 2010.Methods: The SD OCT images were evaluated for morphologic features of the choroid, including the shape of the choroid–scleral border, location of the thickest point of choroid, and regions of focal choroidal thinning. Total choroidal thickness ...

      Read Full Article
    20. 4D dynamic imaging of the eye using ultrahigh speed SS-OCT

      4D dynamic imaging of the eye using ultrahigh speed SS-OCT

      Recent advances in swept-source / Fourier domain optical coherence tomography (SS-OCT) technology enable in vivo ultrahigh speed imaging, offering a promising technique for four-dimensional (4-D) imaging of the eye. Using an ultrahigh speed tunable vertical cavity surface emitting laser (VCSEL) light source based SS-OCT prototype system, we performed imaging of human eye dynamics in four different imaging modes: 1) Pupillary reaction to light at 200,000 axial scans per second and 9 μm resolution in tissue. 2) Anterior eye focusing dynamics at 100,000 axial scans per second and 9 μm resolution in tissue. 3) Tear film break up at 50 ...

      Read Full Article
    21. High-precision, high-accuracy ultralong-range swept-source optical coherence tomography using vertical cavity surface emitting laser light source

      High-precision, high-accuracy ultralong-range swept-source optical coherence tomography using vertical cavity surface emitting laser light source

      We demonstrate ultralong-range swept-source optical coherence tomography (OCT) imaging using vertical cavity surface emitting laser technology. The ability to adjust laser parameters and high-speed acquisition enables imaging ranges from a few centimeters up to meters using the same instrument. We discuss the challenges of long-range OCT imaging. In vivohuman-eye imaging and optical component characterization are presented. The precision and accuracy of OCT-based measurements are assessed and are important for ocular biometry and reproducible intraocular distance measurement before cataract surgery. Additionally, meter-range measurement of fiber length and multicentimeter-range imaging are reported. 3D visualization supports a class of industrial imaging applications ...

      Read Full Article
    22. In vivo imaging of the rodent eye with swept source/Fourier domain OCT

      In vivo imaging of the rodent eye with swept source/Fourier domain OCT

      Swept source/Fourier domain OCT is demonstrated for in vivo imaging of the rodent eye. Using commercial swept laser technology, we developed a prototype OCT imaging system for small animal ocular imaging operating in the 1050 nm wavelength range at an axial scan rate of 100 kHz with ~6 µm axial resolution. The high imaging speed enables volumetric imaging with high axial scan densities, measuring high flow velocities in vessels, and repeated volumetric imaging over time. The 1050 nm wavelength light provides increased penetration into tissue compared to standard commercial OCT systems at 850 nm. The long imaging range enables ...

      Read Full Article
    23. Phase-sensitive swept-source optical coherence tomography imaging of the human retina with a vertical cavity surface-emitting laser light source

      Phase-sensitive swept-source optical coherence tomography imaging of the human retina with a vertical cavity surface-emitting laser light source

      Despite the challenges in achieving high phase stability, Doppler swept-source/Fourier-domain optical coherence tomography (OCT) has advantages of less fringe washout and faster imaging speeds compared to spectral/Fourier-domain detection. This Letter demonstrates swept-source OCT with a vertical cavity surface-emitting laser light source at 400 kHz sweep rate for phase-sensitive Doppler imaging, measuring pulsatile total retinal blood flow with high sensitivity and phase stability. A robust, simple, and computationally efficient phase stabilization approach for phase-sensitive swept-source imaging is also presented.

      Read Full Article
    1-24 of 33 1 2 »
  1. Categories

    1. Applications:

      Art, Cardiology, Dentistry, Dermatology, Developmental Biology, Gastroenterology, Gynecology, Microscopy, NDE/NDT, Neurology, Oncology, Ophthalmology, Other Non-Medical, Otolaryngology, Pulmonology, Urology
    2. Business News:

      Acquisition, Clinical Trials, Funding, Other Business News, Partnership, Patents
    3. Technology:

      Broadband Sources, Probes, Tunable Sources
    4. Miscellaneous:

      Jobs & Studentships, Student Theses, Textbooks
  2. Topics in the News

    1. (33 articles) Massachusetts Institute of Technology
    2. (33 articles) Jonathan J. Liu
    3. (33 articles) James G. Fujimoto
    4. (21 articles) Tufts University
    5. (20 articles) Jay S. Duker
    6. (17 articles) Benjamin M. Potsaid
    7. (16 articles) University of Erlangen
    8. (16 articles) Martin F. Kraus
    9. (15 articles) Thorlabs
    10. (14 articles) Ireneusz Grulkowski
  3. Popular Articles

  4. Picture Gallery

    Retinal blood flow measurement with ultrahigh-speed swept-source / Fourier domain optical coherence tomography Total retinal blood flow measurement with ultrahigh speed swept source/Fourier domain OCT Speckle reduction in swept source optical coherence tomography images with slow-axis averaging Split-spectrum amplitude-decorrelation angiography with optical coherence tomography Motion correction in optical coherence tomography volumes on a per A-scan basis using orthogonal scan patterns Phase-sensitive swept-source optical coherence tomography imaging of the human retina with a vertical cavity surface-emitting laser light source Automated lamina cribrosa microstructural segmentation in optical coherence tomography scans of healthy and glaucomatous eyes Feature Of The Week 2/16/14: En Face Enhanced-Depth Swept-Source Optical Coherence Tomography Features of Chronic Central Serous Chorioretinopath Feature Of The Week 4/2/14: A Compact High-Performance Hand-Held Device for Extending Ophthalmic OCT to New Points of Care (Narrated Presentation) Improving Plaque Classification With Optical Coherence Tomography Optical coherence tomography in oral cancer: A transpiring domain 3D printing of the choroidal vessels and tumours based on optical coherence tomography