scholarly journals WAVELENGTH PROBING OPTICAL COHERENCE TOMOGRAPHY

2011 ◽  
Vol 04 (01) ◽  
pp. 79-88
Author(s):  
SHOUDE CHANG ◽  
YOUXIN MAO

In swept-source optical coherence tomography (SSOCT), the swept-source stimulates system by a series of wavelengths in time sequence; a photo detector then collects all reflected/backscattered light from testing sample as the components of Fourier series. Due to the nature of the SSOCT, the processing in spectral domain can merge multiple swept-sources with different central wavelengths, which greatly increases the resolution of the OCT imaging. In the wavelength probing OCT, a standard broadband SSOCT system is used to extract the internal structure of the sample, and another narrow band light can be used to probe the spectral feature of the sample at the probing wavelength.

2021 ◽  
pp. 247412642199733
Author(s):  
Kyle D. Kovacs ◽  
M. Abdallah Mahrous ◽  
Luis Gonzalez ◽  
Benjamin E. Botsford ◽  
Tamara L. Lenis ◽  
...  

Purpose: This work aims to evaluate the clinical utility and feasibility of a novel scanning laser ophthalmoscope-based navigated ultra-widefield swept-source optical coherence tomography (UWF SS-OCT) imaging system. Methods: A retrospective, single-center, consecutive case series evaluated patients between September 2019 and October 2020 with UWF SS-OCT (modified Optos P200TxE, Optos PLC) as part of routine retinal care. The logistics of image acquisition, interpretability of images captured, nature of the peripheral abnormality, and clinical utility in management decisions were recorded. Results: Eighty-two eyes from 72 patients were included. Patients were aged 59.4 ± 17.1 years (range, 8-87 years). During imaging, 4.4 series of images were obtained in 4.1 minutes, with 86.4% of the image series deemed to be diagnostic of the peripheral pathology on blinded image review. The most common pathologic findings were chorioretinal scars (18 eyes). In 31 (38%) eyes, these images were meaningful in supporting clinical decision-making with definitive findings. Diagnoses imaged included retinal detachment combined with retinoschisis, retinal hole with overlying vitreous traction and subretinal fluid, vitreous inflammation overlying a peripheral scar, Coats disease, and peripheral retinal traction in sickle cell retinopathy. Conclusions: Navigated UWF SS-OCT imaging was clinically practical and provided high-quality characterization of peripheral retinal lesions for all eyes. Images directly contributed to management plans, including laser, injection or surgical treatment, for a clinically meaningful set of patients (38%). Future studies are needed to further assess the value of this imaging modality and its role in diagnosing, monitoring, and treating peripheral lesions.


2016 ◽  
Vol 7 (2) ◽  
pp. 354-358
Author(s):  
Yu Ichioka ◽  
Akihito Uji ◽  
Nagahisa Yoshimura

Background: To present an intraoperative acute Descemet’s fold formation using swept-source optical coherence tomography (SS-OCT) imaging. Case Report: A 67-year-old man complaining of reduced visual acuity in the left eye. A 25-gauge pars plana vitrectomy combined with phacoemulsification cataract surgery was performed to remove the vitreomacular traction. When hydro-sealing was performed, striae rapidly spread in the cornea. SS-OCT B-scan images performed on postoperative day 1 revealed a wavy Descemet’s membrane that might correspond to Descemet’s folds. Pairs of hypo- and hyperreflective narrow lesions running from the wavy Descemet’s membrane to almost half of the thickness of the whole cornea were observed. En face OCT imaging clearly showed the stromal fold, which continuously spread from the Descemet’s fold. Conclusion: The stromal fold might be due to the focal bulge of the stroma posteriorly caused by the rapid volume increase of the stroma which could push Descemet’s membrane posteriorly, thereby forming a wavy Descemet’s membrane layer.


2021 ◽  
Author(s):  
Marjan Razani

This dissertation describes techniques that use Optical Coherence Tomography techniques developed for the detection of shear wave propagation in different phantoms, and the use of such waves to enhance the transport of nanoparticles in tissue equivalent phantoms. In the first study, we explored the potential of measuring shear wave propagation using optical co-herence elastography (OCE) in an inhomogeneous phantom and carotid artery samples based on a swept source optical coherence tomography (OCT) system. Shear waves were generated using a piezoelectric transducer transmitting sine-wave bursts of 400 μs duration, applying acoustic radiation force (ARF) to inhomogeneous phantoms and carotid artery samples, syn-chronized with a swept-source OCT (SS-OCT) imaging system. The phantoms were com-posed of gelatin and titanium dioxide whereas the carotid artery samples were embedded in propagating shear waves in inhomogeneous tissue equivalent phantoms and carotid artery samples using the ARF of an ultrasound transducer, and measuring the shear wave speed and its associated properties in the different layers with OCT phase maps. In the second study, we present a technique to image the enhanced particle displacement generated using an acoustic radiation force (ARF) excitation source. A MEMS-VCSEL swept source Optical Coherence Tomography (SS-OCT) system with a center wavelength of 1310 nm, a bandwidth of 100nm, and an A-scan rate of 100 kHz was used to detect gold nanoparticle displacement. ARF was applied after the nanoparticles diffused into a collagen matrix (of different collagen concen-trations and for a tissue engineered MCF-7 breast cancer cell construct). Differential OCT speckle variance images with and without the ARF were used to estimate the particle dis-placement. The images were used to detect the microscopic enhancement of nanoparticle displacement generated by the ARF. Using this OCT imaging technique, the enhanced transport of particles though a collagen gel after using an ARF excitation was imaged and analysed.


2021 ◽  
Author(s):  
Marjan Razani

This dissertation describes techniques that use Optical Coherence Tomography techniques developed for the detection of shear wave propagation in different phantoms, and the use of such waves to enhance the transport of nanoparticles in tissue equivalent phantoms. In the first study, we explored the potential of measuring shear wave propagation using optical co-herence elastography (OCE) in an inhomogeneous phantom and carotid artery samples based on a swept source optical coherence tomography (OCT) system. Shear waves were generated using a piezoelectric transducer transmitting sine-wave bursts of 400 μs duration, applying acoustic radiation force (ARF) to inhomogeneous phantoms and carotid artery samples, syn-chronized with a swept-source OCT (SS-OCT) imaging system. The phantoms were com-posed of gelatin and titanium dioxide whereas the carotid artery samples were embedded in propagating shear waves in inhomogeneous tissue equivalent phantoms and carotid artery samples using the ARF of an ultrasound transducer, and measuring the shear wave speed and its associated properties in the different layers with OCT phase maps. In the second study, we present a technique to image the enhanced particle displacement generated using an acoustic radiation force (ARF) excitation source. A MEMS-VCSEL swept source Optical Coherence Tomography (SS-OCT) system with a center wavelength of 1310 nm, a bandwidth of 100nm, and an A-scan rate of 100 kHz was used to detect gold nanoparticle displacement. ARF was applied after the nanoparticles diffused into a collagen matrix (of different collagen concen-trations and for a tissue engineered MCF-7 breast cancer cell construct). Differential OCT speckle variance images with and without the ARF were used to estimate the particle dis-placement. The images were used to detect the microscopic enhancement of nanoparticle displacement generated by the ARF. Using this OCT imaging technique, the enhanced transport of particles though a collagen gel after using an ARF excitation was imaged and analysed.


2020 ◽  
Vol 10 (14) ◽  
pp. 4936
Author(s):  
Pingping Jia ◽  
Hong Zhao ◽  
Yuwei Qin

A high-speed, high-resolution swept-source optical coherence tomography (SS-OCT) is presented for focusing lens imaging and a k-domain uniform algorithm is adopted to find the wave number phase equalization. The radius of curvature of the laser focusing lens was obtained using a curve-fitting algorithm. The experimental results demonstrate that the measuring accuracy of the proposed SS-OCT system is higher than the laser confocal microscope. The SS-OCT system has great potential for surface topography measurement and defect inspection of the focusing lens.


Author(s):  
José Ignacio Fernández-Vigo ◽  
Hang Shi ◽  
Bárbara Burgos-Blasco ◽  
Lucía De-Pablo-Gómez-de-Liaño ◽  
Ignacio Almorín-Fernández-Vigo ◽  
...  

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