1. 1-24 of 271 1 2 3 4 ... 10 11 12 »
    1. Technology developments and biomedical applications of polarization-sensitive optical coherence tomography

      Technology developments and biomedical applications of polarization-sensitive optical coherence tomography

      Polarization-sensitive optical coherence tomography (PS-OCT) enables depth-resolved mapping of sample polarization information, such as phase-retardation and optical axis orientation, which is particularly useful when the nano-scale organization of tissue that are difficult to be observed in the intensity images of a regular optical coherence tomography (OCT). In this review, we survey two types of methods and systems of PS-OCT. The first type is PS-OCT with single input polarization state, which contain bulk optics or polarization maintaining fiber (PMF) based systems and single-mode fiber (SMF) based systems. The second type is PS-OCT with two different input polarization states, which contain SMF ...

      Read Full Article
    2. Longitudinal analysis of the structural pattern of pseudophakic cystoid macular edema using multimodal imaging

      Longitudinal analysis of the structural pattern of pseudophakic cystoid macular edema using multimodal imaging

      Purpose To describe the relationship between pseudophakic cystoid macular edema (CME) progression and retinal structural changes observed by spectral-domain optical coherence tomography (SD-OCT) and fluorescein angiography. Methods Retrospective, consecutive, longitudinal imaging analysis of patients with acute pseudophakic cystoid macular edema. Two observers at two study centers evaluated all images and categorized the macular structural features based on the retinal layer involved with cystic changes and/or subretinal fluid. A time series of the structural pattern and visual acuity was constructed for 1-month intervals over a 6-month study period. Results Thirty nine patients presented with CME. The mean time since cataract ...

      Read Full Article
    3. Analysis of the ganglion cell layer and photoreceptor layer using optical coherence tomography after idiopathic epiretinal membrane surgery

      Analysis of the ganglion cell layer and photoreceptor layer using optical coherence tomography after idiopathic epiretinal membrane surgery

      Dear Editor, We appreciate Dr. Iuliano for his interest and comments regarding our article, and we are pleased to share our opinions regarding visual prognosis after epiretinal membrane (ERM) surgery. Studies from Dr. Iuliano’s group and our group have shown that the ganglion cell layer (GCL) is a significant factor in determining visual acuity in idiopathic ERM [ 1 , 2 ]. A decrease in the thickness of the GCL was correlated with postoperative visual recovery in their study,[ 1 ] whereas thinning of the GCL was correlated with poor visual acuity in our study [ 2 ]. We agree with Dr. Iuliano’s comment ...

      Read Full Article
    4. Impact of drug-eluting balloon (pre- or post-) dilation on neointima formation in de novo lesions treated by bare-metal stent: the IN-PACT CORO trial

      Impact of drug-eluting balloon (pre- or post-) dilation on neointima formation in de novo lesions treated by bare-metal stent: the IN-PACT CORO trial

      The efficacy of DEB in modifying the high restenosis risk associated with BMS implantation is doubtful. Optical coherence tomography (OCT) may allow precise assessment of neointimal formation after stent implantation. We performed a single-center, prospective, 1:2 randomized trial comparing BMS implantation alone (BMS group) vs. additional DEB (DEB group). DEB patients were further randomized 1:1 to DEB before stenting (pre-DEB group), or after stenting (post-DEB group). Primary endpoint was OCT-assessed neointimal hyperplasia (expressed both as mean in-stent neointimal area and as percentage obstruction of the mean stent area) at 6 months. Secondary endpoints were the percentage of uncovered ...

      Read Full Article
      Mentions: Francesco Prati
    5. Neoatherosclerosis causing edge in-stent restenosis: optical coherence tomography findings

      Neoatherosclerosis causing edge in-stent restenosis: optical coherence tomography findings

      A patient presenting with ‘edge’ in-stent restenosis 12 years after the implantation of a bare-metal stent in the mid-left anterior descending coronary artery is described. Optical coherence tomography disclosed the presence of ruptured neoatherosclerosis at the stent edge. The value of this imaging technique to unravel this unique underlying anatomic substrate is discussed. The therapy of choice for patients presenting with edge in-stent restenosis (ISR) is reviewed.

      Read Full Article
      Mentions: Fernando Alfonso
    6. Application of Optical Coherence Tomography (OCT) for Diagnosis of Caries, Cracks, and Defects of Restorations

      Application of Optical Coherence Tomography (OCT) for Diagnosis of Caries, Cracks, and Defects of Restorations

      Optical coherence tomography (OCT) is a noninvasive technique providing cross-sectional images of a tooth structure. This review describes the use of OCT for detecting dental caries, tooth fractures, and interfacial gaps in intraoral restorations. OCT can be a reliable and an accurate method and a safer alternative to X-ray radiography.

      Read Full Article
    7. Vascular distribution imaging of dorsal skin window chamber in mouse with spectral domain optical coherence tomography

      Vascular distribution imaging of dorsal skin window chamber in mouse with spectral domain optical coherence tomography

      Doppler optical coherence tomography or optical Doppler tomography (ODT) has been demonstrated to spatially localize flow velocity mapping as well as to obtain images of microstructure of samples simultaneously. In recent decades, spectral domain Doppler optical coherence tomography (OCT) has been applied to observe three-dimensional (3D) vascular distribution. In this study, we developed a spectral domain optical coherence tomography system (SD-OCT) using super luminescent diode (SLD) as light source. The center wavelength of SLD is 835 nm with a 45-nm bandwidth. Theoretically, the transverse resolution, axial resolution and penetration depth of this SD-OCT system are 6.13 μm, 6.84 ...

      Read Full Article
    8. Comparison of the current and a new RTVue OCT software version for detection of ganglion cell complex changes due to cataract surgery

      Comparison of the current and a new RTVue OCT software version for detection of ganglion cell complex changes due to cataract surgery

      The purpose was to compare the current (6.3) and a novel software version (6.12) of the RTVue-100 optical coherence tomograph (RTVue OCT) for ganglion cell complex (GCC) and retinal nerve fibre layer thickness (RNFLT) changes after phacoemulsification in healthy cataract eyes, and to investigate whether version 6.12, in which image segmentation is improved, provides benefits over version 6.3 for RNFLT and GCC imaging via mild cataract. One eye of 22 consecutive healthy cataract patients were imaged before and 1 month after uncomplicated cataract surgery using RTVue-100 OCT software version 6.3. The images were analysed with ...

      Read Full Article
    9. Spectral domain optical coherence tomography imaging of tubercular chorioretinitis and intraretinal granuloma. Intraretinal tuberculosis: a case report

      Spectral domain optical coherence tomography imaging of tubercular chorioretinitis and intraretinal granuloma. Intraretinal tuberculosis: a case report

      The aim of this study is to report the clinical and spectral domain optical coherence tomography (SD-OCT) findings in a patient suffering from ulcerative colitis with bilateral tubercular chorioretinitis and intraretinal granuloma regressed with systemic antitubercular therapy (ATT). This study is a case report of a 33-year-old Bangladeshi male with ulcerative colitis treated with oral corticosteroids and azathioprine who was referred to our department with a diagnosis of central serous chorioretinopathy. Serological tests, the Mantoux skin test, complete ophthalmologic examination, ocular fundus photography, fundus fluorescein angiography, and SD-OCT scans were performed. The ophthalmological inflammatory pattern and serological investigations provided an ...

      Read Full Article
    10. Applicability of the ISNT and IST rules on retinal nerve fiber layer measurement on spectral-domain optical coherence tomography in normal Indian children

      Applicability of the ISNT and IST rules on retinal nerve fiber layer measurement on spectral-domain optical coherence tomography in normal Indian children

      Background To determine the applicability of the ISNT (inferior>superior>nasal>temporal) and IST (inferior>superior>temporal) rules on retinal nerve fiber layer (RNFL) measurement on spectral-domain optical coherence tomography (SD-OCT) in normal children. Methods A prospective, cross-sectional study including consecutive subjects between the ages of 5–18 years who were born at term (≥37 weeks gestational age) and with a normal birth weight (≥2500 g) presenting to the out-patient department for refractive error examination. RNFL measurement was done on Spectralis SD-OCT. Exclusion criteria were best-corrected visual acuity less than 20/20, spherical equivalent (SE) > ± 5 diopter (D), applanation IOP ...

      Read Full Article
    11. Correlation between depth and area of retinal nerve fiber layer defect as measured by spectral domain optical coherence tomography

      Correlation between depth and area of retinal nerve fiber layer defect as measured by spectral domain optical coherence tomography

      Background To evaluate the correlation between the depth and area of retinal nerve fiber layer (RNFL) defect, as measured on an RNFL map of spectral-domain optical coherence tomography (SD-OCT). Methods The RNFL of 472 glaucoma subjects and of 217 healthy subjects was imaged by an SD-OCT. RNFL defect depth and area on the RNFL map were expressed as an RNFL defect depth percentage index (RDPI) and an RNFL defect area index (RDAI), respectively, according to the following two formulas: 100×[1–{summation of thicknesses of RNFL defects/summation of thicknesses of upper 95th percentile range of age-matched healthy subjects in ...

      Read Full Article
    12. Choroidal involvement in Rosai-Dorfman syndrome may be depicted and followed using enhanced depth imaging optical coherence tomography (EDI-OCT)

      Choroidal involvement in Rosai-Dorfman syndrome may be depicted and followed using enhanced depth imaging optical coherence tomography (EDI-OCT)

      Dear Editor, We read with interest the recently published case report by Vermeulen et al. [ 1 ] regarding “Rosai–Dorfman disease presenting as choroidal melanoma”. We previously published a similar presentation of a patient that underwent systemic work-up for bilateral choroidal masses [ 2 ]. Our patient initially presented with minimal visual complaints and best-corrected visual acuity of 20/20 OU. Sub-papillomacular bundle, amelanotic choroidal masses OU were discovered on dilated fundus exam. Initial work-up demonstrated focal pigment epithelial detachment OD but overall intact outer retinal layers OU on spectral domain optical coherence tomography (SD-OCT). Unlike the case report by Vermeulen et al ...

      Read Full Article
    13. Predictors of 1-year visual outcome in OCT analysis comparing ranibizumab monotherapy versus combination therapy with PDT in exsudative age-related macular degeneration

      Predictors of 1-year visual outcome in OCT analysis comparing ranibizumab monotherapy versus combination therapy with PDT in exsudative age-related macular degeneration

      Aim The aim of this study was to find predictive factors of 1-year visual outcome, analyzing novel optical coherence tomography (OCT) biomarkers in exsudative age-related macular degeneration (choroidal neovascularization (CNV)) in two groups of different treatment modalities. Methods In all, 34 consecutive patients with new-onset CNV were randomized 1:1 to receive either ranibizumab monotherapy or ranibizumab combined with photodynamic therapy (PDT) with verteporfin. After three initial injections with ranibizumab, re-treatment was performed according to an as-needed scheme; PDT was performed once at baseline. Best-corrected visual acuity (BCVA) and OCT parameters like central macular volume (CMV), central macular thickness (or ...

      Read Full Article
    14. Automated measurement of stent strut coverage in intravascular optical coherence tomography

      Automated measurement of stent strut coverage in intravascular optical coherence tomography

      Optical coherence tomography (OCT) is a non-invasive, cross-sectional imaging modality that has become a prominent imaging method in percutaneous intracoronary intervention. We present an automated detection algorithm for stent strut coordinates and coverage in OCT images. The algorithm for stent strut detection is composed of a coordinate transformation from the polar to the Cartesian domains and application of second derivative operators in the radial and the circumferential directions. Local region-based active contouring was employed to detect lumen boundaries. We applied the method to the OCT pullback images acquired from human patients in vivo to quantitatively measure stent strut coverage. The ...

      Read Full Article
    15. Precise measurement of volume of eccrine sweat gland in mental sweating by optical coherence tomography

      Precise measurement of volume of eccrine sweat gland in mental sweating by optical coherence tomography

      We have demonstrated dynamic analysis of the physiological function of eccrine sweat glands underneath skin surface by optical coherence tomography (OCT). In this paper, we propose a method for extraction of the specific eccrine sweat gland by means of the connected component extraction process and the adaptive threshold method, where the en face OCT images are constructed by the swept-source OCT. In the experiment, we demonstrate precise measurement of the volume of the sweat gland in response to the external stimulus.

      Read Full Article
    16. Quantification of fibrous cap thickness in intracoronary optical coherence tomography with a contour segmentation method based on dynamic programming

      Quantification of fibrous cap thickness in intracoronary optical coherence tomography with a contour segmentation method based on dynamic programming

      Objectives Fibrous cap thickness is the most critical component of plaque stability. Therefore, in vivo quantification of cap thickness could yield valuable information for estimating the risk of plaque rupture. In the context of preoperative planning and perioperative decision making, intracoronary optical coherence tomography imaging can provide a very detailed characterization of the arterial wall structure. However, visual interpretation of the images is laborious, subject to variability, and therefore not always sufficiently reliable for immediate decision of treatment. Methods A novel semiautomatic segmentation method to quantify coronary fibrous cap thickness in optical coherence tomography is introduced. To cope with the ...

      Read Full Article
    17. Optical coherence tomography features of angiographic complex and smooth lesions in acute coronary syndromes

      Optical coherence tomography features of angiographic complex and smooth lesions in acute coronary syndromes

      Plaque rupture (PR) and superimposed thrombosis have been shown as the most frequent underlying substrate in acute coronary syndromes (ACS). Coronary angiography is a luminogram not able to define in vivo features of the culprit plaques. The aim of the study was to use optical coherence tomography (OCT) to investigate the pathology underlying complex (CL) and non-complex angiographic lesions (NCL). We retrospectively enrolled 107 ACS patients admitted to our institution; 83 with non-ST elevation ACS (NSTE-ACS) and 24 with ST-elevation myocardial infarction. Coronary angiography was performed and culprit lesions were classified according to Ambrose criteria into NCL (n = 47) and ...

      Read Full Article
    18. Visualization of dynamic boiling processes using high-speed optical coherence tomography

      Visualization of dynamic boiling processes using high-speed optical coherence tomography

      Investigating microscale nucleate boiling processes with high heat flux requires experimental visualization and quantification with high spatial resolution in the micrometer range as well as a sufficient temporal resolution. Numerous measurement techniques are employed for providing comprehensive experimental data on microscale boiling processes and other multiphase flows. In this context, optical coherence tomography (OCT) has been introduced recently for the visualization of quasistatic growing vapor bubbles in turbid fluids with a high spatial resolution. Since OCT detects backscattered light, only one optical access is necessary and OCT is feasible for measurements in turbid media, where other imaging techniques fail. Within ...

      Read Full Article
    19. Spectral domain optical coherence tomography imaging of mucopolysaccharidoses I, II, and VI A

      Spectral domain optical coherence tomography imaging of mucopolysaccharidoses I, II, and VI A

      Purpose The purpose of this study was to describe the spectral domain optical coherence tomography (SD-OCT) characteristics of patients with retinal manifestations of mucopolysaccharidoses (MPSs) I, II, and IV A. Design The research was a prospective, observational study. Methods Fourteen consecutive patients with variants of MPS and 15 healthy subjects underwent ophthalmic assessments including fundus examinations and SD-OCT. Results The fundus examinations revealed that four patients (two MPS I and two MPS II ) had pigmented retinopathy in both eyes. In addition, one MPS II patient had cystoid macular edema and two MPS II patients had abnormal disc morphology. SD-OCT revealed ...

      Read Full Article
    20. Analysis of choroidal folds in acute Vogt–Koyanagi–Harada disease using high-penetration optical coherence tomography

      Analysis of choroidal folds in acute Vogt–Koyanagi–Harada disease using high-penetration optical coherence tomography

      Purpose To characterize patients with Vogt–Koyanagi–Harada (VKH) disease with choroidal folds (CFs) and determine how the foveal choroidal thickness changes after initial treatment using high-penetration optical coherence tomography (HP-OCT). Methods In this retrospective observational study, we analyzed 42 eyes of 21 patients with new-onset VKH disease to determine the demographic and clinical differences between patients with and without CFs. Results Twenty-four eyes (57.1 %) of 13 patients with VKH disease had CFs. The mean age ( p  = 0.0009) of patients with CFs was significantly higher than that of those without CFs (49.1 vs 39.4 years respectively ...

      Read Full Article
    21. Current and evolving uses of optical coherence tomography in the genitourinary tract

      Current and evolving uses of optical coherence tomography in the genitourinary tract

      Optical coherence tomography is an emerging imaging modality that provides high-resolution, real-time, cross-sectional visualization of urologic tissue with promising results. Early studies have demonstrated detailed, accurate histologic information of tissues sampled. Optical coherence tomography (OCT) has also been applied in evaluating malignancy of the bladder, prostate, and kidney. In the bladder, it can assist in the identification, biopsy, and intraoperative resection of lesions suspicious for bladder cancer. Intraoperative use of OCT during radical prostatectomy can improve visualization of the neurovascular bundle and surgical margins. Several small, ex vivo studies have also shown promising results in the ability of OCT to ...

      Read Full Article
    22. Fourier domain optical coherence tomography with ultralong depth range

      Fourier domain optical coherence tomography with ultralong depth range

      The depth ranges of typical implementations of Fourier domain optical coherence tomography (FDOCT), including spectral domain OCT (SDOCT) and swept source OCT (SSOCT), are limited to several millimeters. To extend the depth range of current OCT systems, two novel systems with ultralong depth range were developed in this study. One is the orthogonal dispersive SDOCT (OD-SDOCT), and the other is the recirculated swept source (R-SS) interferometer/OCT. No compromise between depth range and depth resolution is required in both systems. The developed OD-SDOCT system realized the longest depth range (over 100 mm) ever achieved by SDOCT, which is ready to ...

      Read Full Article
    23. Electroretinography and optical coherence tomography reveal abnormal post-photoreceptoral activity and altered retinal lamination in patients with enhanced S-cone syndrome

      Electroretinography and optical coherence tomography reveal abnormal post-photoreceptoral activity and altered retinal lamination in patients with enhanced S-cone syndrome

      Purpose To compare functional abnormalities of enhanced S-cone syndrome ( ESCS ), as examined using standard and extended electroretinography (ERG), with structural findings and retinal architecture obtained by spectral domain optical coherence tomography (SD-OCT). Methods Four patients with ESCS underwent standard full-field and multifocal ERGs, with extended S-cone and ON/OFF ERG protocols also performed. SD-OCT was also carried out, and longitudinal reflectivity profiles (LRPs) were calculated for the perifoveolar retina. Results All four patients exhibited pathognomonic full-field ERG findings for ESCS , with delayed responses of similar waveforms to the same intensity flash under both scotopic and photopic conditions. The amplitudes of ...

      Read Full Article
    24. The outer choroidoscleral boundary in full-thickness macular holes before and after surgery—a swept-source OCT stud

      The outer choroidoscleral boundary in full-thickness macular holes before and after surgery—a swept-source OCT stud

      Purpose To report on choroidal thickness and the morphology of the outer choroidoscleral boundary in swept-source OCT in patients with full-thickness macular holes (FTMH) before and after surgery. Methods Single center matched case–control study of 32 patients with FTMH (group 1), fellow eyes (group 2), and 32 eyes of 32 healthy controls (group 3). All eyes from group 1 had vitrectomy with a minimum follow-up of 3 months. Main outcome measures were the visibility and regularity of the outer choroidoscleral boundary (CSB), and additionally the eventual visibility of the suprachoroidal layer (SCL). Results Choroidal thickness was indifferent between groups ...

      Read Full Article
    1-24 of 271 1 2 3 4 ... 10 11 12 »
  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