scholarly journals Retinal Imaging of Infants on Spectral Domain Optical Coherence Tomography

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Anand Vinekar ◽  
Shwetha Mangalesh ◽  
Chaitra Jayadev ◽  
Ramiro S. Maldonado ◽  
Noel Bauer ◽  
...  
Keyword(s):  
Spectral Domain ◽  
Current Status ◽  
Acquisition Time ◽  
Imaging Device ◽  
Short Acquisition Time ◽  
Visual Potential ◽  
Detailed Assessment ◽  
First Year Of Life ◽  
Sd Oct

Spectral domain coherence tomography (SD OCT) has become an important tool in the management of pediatric retinal diseases. It is a noncontact imaging device that provides detailed assessment of the microanatomy and pathology of the infant retina with a short acquisition time allowing office examination without the requirement of anesthesia. Our understanding of the development and maturation of the infant fovea has been enhanced by SD OCT allowing an in vivo assessment that correlates with histopathology. This has helped us understand the critical correlation of foveal development with visual potential in the first year of life and beyond. In this review, we summarize the recent literature on the clinical applications of SD OCT in studying the pathoanatomy of the infant macula, its ability to detect subclinical features, and its correlation with disease and vision. Retinopathy of prematurity and macular edema have been discussed in detail. The review also summarizes the current status of SD OCT in other infant retinal conditions, imaging the optic nerve, the choroid, and the retinal nerve fibre in infants and children, and suggests future areas of research.

scholarly journals Optimization of spectral-domain optical coherence tomography with a supercontinuum source for in vivo motion detection of low reflective outer hair cells in guinea pig cochleae

2021 ◽  
Author(s):  
Fumiaki Nin ◽  
Samuel Choi ◽  
Takeru Ota ◽  
Zhang Qi ◽  
Hiroshi Hibino
Keyword(s):  
Optical Coherence Tomography ◽  
High Resolution ◽  
Guinea Pig ◽  
Hair Cells ◽  
Sensory Epithelium ◽  
Outer Hair Cells ◽  
Acquisition Time ◽  
Total Acquisition Time ◽  
Sd Oct

AbstractSound evokes sub-nanoscale vibration within the sensory epithelium. The epithelium contains not only immotile cells but also contractile outer hair cells (OHCs) that actively shrink and elongate synchronously with the sound. However, the in vivo motion of OHCs has remained undetermined. The aim of this work is to perform high-resolution and -accuracy vibrometry in live guinea pigs with an SC-introduced spectral-domain optical coherence tomography system (SD-OCT). In this study, to reveal the effective contribution of SC source in the recording of the low reflective materials with the short total acquisition time, we compare the performances of the SC-introduced SD-OCT (SCSD-OCT) to that of the conventional SD-OCT. As inanimate comparison objects, we record a mirror, a piezo actuator, and glass windows. For the measurements in biological materials, we use in/ex vivo guinea pig cochleae. Our study achieved the optimization of a SD-OCT system for high-resolution in vivo vibrometry in the cochlear sensory epithelium, termed the organ of Corti, in mammalian cochlea. By introducing a supercontinuum (SC) light source and reducing the total acquisition time, we improve the axial resolution and overcome the difficulty in recording the low reflective material in the presence of biological noise. The high power of the SC source enables the system to achieve a spatial resolution of 1.72 ± 0.00 μm on a mirror and reducing the total acquisition time contributes to the high spatial accuracy of sub-nanoscale vibrometry. Our findings reveal the vibrations at the apical/basal region of OHCs and the extracellular matrix, basilar membrane.

scholarly journals Design and Implementation Guidelines for a Modular Spectral-Domain Optical Coherence Tomography Scanner

2018 ◽  
Vol 2018 ◽  
pp. 1-22 ◽  
Author(s):  
Farid Atry ◽  
Israel Jacob De La Rosa ◽  
Kevin R. Rarick ◽  
Ramin Pashaie
Keyword(s):  
Optical Coherence Tomography ◽  
Imaging System ◽  
Optical Design ◽  
Spectral Domain ◽  
Design Parameters ◽  
Optical Coherence ◽  
Custom Made ◽  
Essential Knowledge ◽  
Sd Oct

In the past decades, spectral-domain optical coherence tomography (SD-OCT) has transformed into a widely popular imaging technology which is used in many research and clinical applications. Despite such fast growth in the field, the technology has not been readily accessible to many research laboratories either due to the cost or inflexibility of the commercially available systems or due to the lack of essential knowledge in the field of optics to develop custom-made scanners that suit specific applications. This paper aims to provide a detailed discussion on the design and development process of a typical SD-OCT scanner. The effects of multiple design parameters, for the main optical and optomechanical components, on the overall performance of the imaging system are analyzed and discussions are provided to serve as a guideline for the development of a custom SD-OCT system. While this article can be generalized for different applications, we will demonstrate the design of a SD-OCT system and representative results for in vivo brain imaging. We explain procedures to measure the axial and transversal resolutions and field of view of the system and to understand the discrepancies between the experimental and theoretical values. The specific aim of this piece is to facilitate the process of constructing custom-made SD-OCT scanners for research groups with minimum understanding of concepts in optical design and medical imaging.

scholarly journals Single Photon, Time-Gated, Phasor-based Fluorescence Lifetime Imaging Through Highly Scattering Medium

2019 ◽  
Author(s):  
Rinat Ankri ◽  
Arkaprabha Basu ◽  
Arin Can Ulku ◽  
Claudio Bruschini ◽  
Edoardo Charbon ◽  
...  
Keyword(s):  
Fluorescence Lifetime ◽  
Fluorescence Intensity ◽  
Single Photon ◽  
Acquisition Time ◽  
Fluorescence Signal ◽  
Wide Field ◽  
Fluorescence Lifetime Imaging ◽  
Short Acquisition Time ◽  
Lifetime Imaging

AbstractFluorescence lifetime imaging (FLI) is a powerful tool for in vitro and non-invasive in vivo biomolecular and cellular investigations. Fluorescence lifetime is an intrinsic characteristic of any fluorescent dye which, to some extent, does not depend on excitation intensity and signal level. However, when used in vivo with visible wavelength emitting fluorophores, FLI is complicated by (i) light scattering as well as absorption by tissues, which significantly reduces fluorescence intensity, (ii) tissue autofluorescence (AF), which decreases the signal to noise ratio and (iii) broadening of the decay signal, which can result in incorrect lifetime estimation. Here, we report the use of a large-frame time-gated single-photon avalanche diode (SPAD) imager, SwissSPAD2, with a very short acquisition time (in the milliseconds range) and a wide-field microscopy format. We use the phasor approach to convert each pixel’s data into its local lifetime. The phasor transformation provides a simple and fast visual method for lifetime imaging and is particularly suitable for in vivo FLI which suffers from deformation of the fluorescence decay, and makes lifetime extraction by standard fitting challenging. We show, for single dyes, that the phasor cloud distribution (of pixels) increases with decay broadening due to scattering and decreasing fluorescence intensity. Yet, as long as the fluorescence signal is higher than the tissue-like phantom AF, a distinct lifetime can still be clearly identified with an appropriate background correction. Lastly, we demonstrate the detection of few hundred thousand A459 cells expressing the fluorescent protein mCyRFP1 through highly scattering phantom layers, despite significant scattering and the presence of the phantom AF.

scholarly journals In VivoComparison of 23- and 25-Gauge Sutureless Vitrectomy Incision Architecture Using Spectral Domain Optical Coherence Tomography

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Anderson Teixeira ◽  
Flavio A. Rezende ◽  
Camila Salaroli ◽  
Nonato Souza ◽  
Benedito Antonio Sousa ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Silicone Oil ◽  
Spectral Domain ◽  
Optical Coherence ◽  
Open Wound ◽  
Longitudinal Length ◽  
Oil Residue ◽  
23 Gauge ◽  
Sd Oct

Purpose. To investigate thein vivoincision architecture using spectral domain optical coherence tomography (SD-OCT) in 23-gauge and 25-gauge transconjunctival suturelesspars planavitrectomy (TSPPV).Methods. A prospective observational study of 22 eyes of 22 patients that underwent three-port 25-gauge (10 eyes) or 23-gauge (12 eyes) TSPPV was performed. The three sclerotomies sites in each eye were analyzed by Corneal Adapter Model (CAM) RTVue SD-OCT (Optovue Inc., Fremont, CA, USA) with wound cross-section images (longitudinal and transversal) on days 1, 7, and 30 postoperatively. Transversal and longitudinal length, location, angle between the conjunctival surface tangent and the incision plane, and architecture deformations were evaluated.Results. All patients (22 eyes) completed the study and surgeries lasted less than 60 minutes. All wounds were obliquely performed, 23-gauge mean angle was 23 ± 5°, and 25-gauge angule was 21 ± 4°. Twenty-three-gauge sclerotomy transversal mean length was 1122 ± 242 μm and 25-gauge transversal sclerotomy mean length was 977 ± 174 μm; 23-gauge longitudinal mean length was 363 ± 42 μm and 25-gauge longitudinal sclerotomy mean length was 234 ±19 μm; 23-gauge open wound thickness mean was 61 ± 28 μm and 25-gauge open wound thickness mean was 22 ± 6 μm. All results were statistically significant (P<0.05). No vitreous incarceration or silicone oil residue was observed in incision sites with both gauges.Conclusions. The 23-gauge and 25-gauge architectural wound constructions were well visualized using CAM SD-OCT. Statistical differences between the two gauges were observed throughout the study period.

scholarly journals MRI Estimation of Global Brain Oxygen Consumption Rate

2010 ◽  
Vol 30 (9) ◽  
pp. 1598-1607 ◽  
Author(s):  
Varsha Jain ◽  
Michael C Langham ◽  
Felix W Wehrli
Keyword(s):  
Magnetic Resonance ◽  
Oxygen Saturation ◽  
Cerebral Metabolism ◽  
Temporal Variations ◽  
Acquisition Time ◽  
Blood Oxygen Saturation ◽  
Short Acquisition Time ◽  
Global Estimate ◽  
Sagittal Sinus

Measuring the global cerebral metabolic rate of oxygen ( CMRO2) is a valuable tool for assessing brain vitality and function. Measurement of blood oxygen saturation ( HbO2) and flow in the major cerebral outflow and inflow vessels can provide a global estimate of CMRO2. We demonstrate a rapid noninvasive method for quantifying CMRO2 by simultaneously measuring venous oxygen saturation in the superior sagittal sinus with magnetic resonance susceptometry-based oximetry, a technique that exploits the intrinsic susceptibility of deoxygenated hemoglobin, and the average blood inflow rate with phase-contrast magnetic resonance imaging. The average venous HbO2, cerebral blood flow, and global CMRO2 values in eight healthy, normal study subjects were 64%±4%, 45.2±3.2 mL per 100 g per minute, and 127±7 μmol per 100 g per minute, respectively. These values are in good agreement with those reported in literature. The technique described is noninvasive, robust, and reproducible for in vivo applications, making it ideal for use in clinical settings for assessing the pathologies associated with dysregulation of cerebral metabolism. In addition, the short acquisition time (∼30 seconds) makes the technique suitable for studying the temporal variations in CMRO2 in response to physiologic challenges.

scholarly journals 3D Curvelet-Based Segmentation and Quantification of Drusen in Optical Coherence Tomography Images

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
M. Esmaeili ◽  
A. M. Dehnavi ◽  
H. Rabbani
Keyword(s):  
Optical Coherence Tomography ◽  
Imaging System ◽  
Imaging Modality ◽  
Age Related Macular Degeneration ◽  
Spectral Domain ◽  
Optical Coherence ◽  
Treatment Protocols ◽  
Age Related ◽  
Sd Oct

Spectral-Domain Optical Coherence Tomography (SD-OCT) is a widely used interferometric diagnostic technique in ophthalmology that provides novel in vivo information of depth-resolved inner and outer retinal structures. This imaging modality can assist clinicians in monitoring the progression of Age-related Macular Degeneration (AMD) by providing high-resolution visualization of drusen. Quantitative tools for assessing drusen volume that are indicative of AMD progression may lead to appropriate metrics for selecting treatment protocols. To address this need, a fully automated algorithm was developed to segment drusen area and volume from SD-OCT images. The proposed algorithm consists of three parts: (1) preprocessing, which includes creating binary mask and removing possible highly reflective posterior hyaloid that is used in accurate detection of inner segment/outer segment (IS/OS) junction layer and Bruch’s membrane (BM) retinal layers; (2) coarse segmentation, in which 3D curvelet transform and graph theory are employed to get the possible candidate drusenoid regions; (3) fine segmentation, in which morphological operators are used to remove falsely extracted elongated structures and get the refined segmentation results. The proposed method was evaluated in 20 publically available volumetric scans acquired by using Bioptigen spectral-domain ophthalmic imaging system. The average true positive and false positive volume fractions (TPVF and FPVF) for the segmentation of drusenoid regions were found to be 89.15% ± 3.76 and 0.17% ± .18%, respectively.

scholarly journals Morphology of Peripheral Vitreoretinal Interface Abnormalities Imaged with Spectral Domain Optical Coherence Tomography

2019 ◽  
Vol 2019 ◽  
pp. 1-5
Author(s):  
Rachel L. Chu ◽  
Nicole A. Pannullo ◽  
Christopher R. Adam ◽  
Mohammad R. Rafieetary ◽  
Eric J. Sigler
Keyword(s):  
Optical Coherence Tomography ◽  
Image Quality ◽  
Imaging Modality ◽  
Structural Features ◽  
Spectral Domain ◽  
Optical Coherence ◽  
Vitreoretinal Interface ◽  
Retinal Breaks ◽  
Sd Oct

The objective of this study is to describe the clinical utility and morphologic characteristics of peripheral vitreoretinal interface abnormalities with spectral domain optical coherence tomography (SD-OCT). A prospective imaging analysis of 43 patients with peripheral vitreoretinal interface abnormalities seen on binocular indirect examination with scleral indentation was done. SD-OCT was evaluated for image quality and structural findings. Laser retinopexy was performed to surround all retinal breaks containing a full-thickness component via SD-OCT. Acceptable image quality for inclusion was obtained in 39/43 (91%) patients. Mean age was 41 ± 22 years, and mean follow-up was 14 ± 1.6 months. Decision to treat was altered following SD-OCT in 5% of the patients. Two cases of previously diagnosed operculated holes were found on SD-OCT to be partial-thickness operculated breaks or focal operculated schisis. Peripheral SD-OCT is a reliable and useful technique to examine the structural features of vitreoretinal interface abnormalities in vivo. This imaging modality is useful in the clinical management of suspected retinal breaks identified with indirect ophthalmoscopy.

scholarly journals In Vivo Corneal Microstructural Changes in Herpetic Stromal Keratitis: A Spectral-Domain Optical Coherence Tomography Analysis

2020 ◽  
Author(s):  
Alejandro Rodriguez-Garcia ◽  
Raul Alfaro-Rangel ◽  
Andres Bustamante-Arias ◽  
Julio C. Hernandez-Camarena
Keyword(s):  
Spectral Domain ◽  
Inactive Disease ◽  
Visual Axis ◽  
Inflammatory Infiltration ◽  
Herpetic Stromal Keratitis ◽  
Microstructural Changes ◽  
Epithelial Remodeling ◽  
Stromal Keratitis ◽  
Sd Oct

Purpose: To describe and analyze the microstructural changes in herpetic stromal keratitis (HSK) observed in vivo by spectral-domain ocular coherence tomography (SD-OCT) at different stages of the disease. Methods: A prospective, cross-sectional, observational, and comparative SD-OCT analysis of corneas with active and inactive keratitis was performed, and the pathologic differences between the necrotizing and non-necrotizing forms of the disease were analyzed. Results: Fifty-three corneas belonging to 43 (81.1%) women and 10 (18.8%) men with a mean age of 41.0 years were included for analysis. Twenty-four (45.3%) eyes had active keratitis, and 29 (54.7%) had inactive keratitis; the majority (83.0%) had the non-necrotizing form. Most corneas (79.1%) with active keratitis showed stromal edema and inflammatory infiltrates. Almost half of the active lesions affected the visual axis, were found at mid-stromal depth, and had a medium density. By contrast, corneas with inactive keratitis were characterized by stromal scarring (89.6%), epithelial remodeling (72.4%), and stromal thinning (68.9%). In contrast to non-necrotizing corneas, those with necrotizing HSK showed severe stromal scarring, inflammatory infiltration, and thinning. Additionally, most necrotizing lesions (77.7%) affected the visual axis and had a higher density (P = 0.010). Conclusion: Active HSK is characterized by significant epithelial and stromal thickening and the inactive disease manifests epithelial remodeling at sites of stromal thinning due to scarring. Necrotizing keratitis is characterized by distorted corneal architecture, substantial stromal inflammatory infiltration, and thinning. In vivo SD-OCT analysis permitted a better understanding of the inflammatory and repair mechanisms occurring in this blinding corneal disease.

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