Associations Between the Retinal/Choroidal Microvasculature and Carotid Plaque in Patients with CHD: An Optical Coherence Tomography Angiography Study
To investigate the associations between retinal/choroidal microvasculature and carotid plaque in patients with CHD assessed by optical coherence tomography angiography (OCTA).
This study included 127 CHD patients with and 79 without carotid plaque. Each patient had both OCTA taken and digitized to determine retinal/choroidal thickness, vessel density and flow area and carotid ultrasound for carotid plaque size and stability measurement. SCP, DCP, out retina and choriocapillaris vessel density, out retina and choriocapillaris flow area, and full retina thickness were analyzed in the fovea centered 6 × 6 mm area. The association between OCTA measurements and carotid plaque characteristics in patients with CHD were evaluated.
The duration of hypertension and DM was significantly longer in CHD patients with carotid plaque than that without (p < 0.001). The mean values for vessel density SCP and DCP (except fovea zone), and choriocapillaris na...
A spatial resolution evaluation method of endoscopic optical coherence tomography system using the annular phantom
As an important biomedical imaging method, endoscopic optical coherence tomography (OCT) is necessary to check its performance regularly. The ordinary plane phantoms are only able to evaluate part of image tangent to the probe. In this research, a spatial resolution estimate method of the endoscope OCT system is proposed. The annular phantom, made by uniformly distributing golden scattered microparticles in polydimethylsiloxane (PDMS), can provide dynamic scanning imaging evaluation of endoscopic OCT system, closer to its actual working status. The point spread function (PSF) analysis method is used to analyze the imaging results of the annular phantom with the endoscopic OCT system. And many scattered particles are statistically analyzed to determine the spatial resolution of the endoscope OCT system. The method is low in cost, simple and convenient. It is valuable for the development of test standards for endoscope OCT systems.
( Read Full Article )
A FBG-OCT Catheter to reconstruct vascular shape in intravascular optical coherence tomography
We propose a novel Fiber Bragg Grating (FBG)-Optical Coherence Tomography (OCT) catheter to reconstruct vascular shape by intravascular OCT imaging of the actual curvature as well as the bending direction of the vascular in real-time. Compared with the traditional OCT catheter, the FBG-OCT catheter uses the FBG encapsulated with half-sectioned stainless-steel tube as a flexural sensitive component. With the 360-degree rotation of the catheter, the encapsulated FBG will produce maximum tension and maximum compression at the bend of the blood vessel, and then get the solution of the curvature and direction of the bending catheter as well as the OCT imaging simultaneously. To test the proposed catheter for real-time measurement, a bending calibration system and a vascular prosthesis model to simulate the actual vascular bending morphology are manufactured through three-dimension (3D) printing. Experimental data shows that the new FBG-OCT catheter can acquire the OCT images and FBG bend...
Scaffold and Edge Vascular Response Following Implantation of Everolimus-Eluting Bioresorbable Vascular Scaffold : A 3-Year Serial Optical Coherence Tomography Study
Objectives This study sought to investigate the in-scaffold vascular response (SVR) and edge vascular response (EVR) after implantation of an everolimus-eluting bioresorbable scaffold (BRS) using serial optical coherence tomography (OCT) imaging. Background Although studies using intravascular ultrasound have evaluated the EVR in metal stents and BRSs, there is a lack of OCT-based SVR and EVR assessment after BRS implantation. Methods In the ABSORB Cohort B (ABSORB Clinical Investigation, Cohort B) study, 23 patients (23 lesions) in Cohort B1 and 17 patients (18 lesions) in Cohort B2 underwent truly serial OCT examinations at 3 different time points (Cohort B1: post-procedure, 6 months, and 2 years; B2: post-procedure, 1 year, and 3 years) after implantation of an 18-mm scaffold. A frame-by-frame OCT analysis was performed at the 5-mm proximal, 5-mm distal edge, and 2-mm in-scaffold margins, whereas the middle 14-mm in-scaffold segment was analyzed at 1-mm intervals. Results The in-...
Effect of the Endothelial Shear Stress Patterns on Neointimal Proliferation Following Drug-Eluting Bioresorbable Vascular Scaffold Implantation : An Optical Coherence Tomography Study
Objectives The goal of this study was to investigate the effect of endothelial shear stress (ESS) on neointimal formation following an Absorb bioresorbable vascular scaffold (BVS) (Abbott Vascular, Santa Clara, California) implantation. Background Cumulative evidence, derived from intravascular ultrasound–based studies, has demonstrated a strong association between local ESS patterns and neointimal formation in bare-metal stents, whereas in drug-eluting stents, there are contradictory data about the effect of ESS on the vessel wall healing process. The effect of ESS on neointimal development following a bioresorbable scaffold implantation remains unclear. Methods Twelve patients with an obstructive lesion in a relatively straight arterial segment, who were treated with an Absorb BVS and had serial optical coherence tomographic examination at baseline and 1-year follow-up, were included in the current analysis. The optical coherence tomographic data acquired at follow-up were u...
Study on effective probe depth of optical coherence tomography system by Monte Carlo simulation
The intensities of Class I and Class II signals at several different probing depths and different coherence lengths are analyzed using a Monte Carlo model with a pencil beam, and the result shows that the longitudinal resolution has influence on the effective probe depth. A Monte Carlo model for optical coherence tomography system with a focused Gaussian beam is proposed. The intensities of Class I and Class II signals at different probing depth for different radius and depth of focus of the beam are simulated using this model. We found that increasing of the depth of focus and decreasing of the beam radius can finitely increase effective probing depth. When the effective probing depth is fixed, optimal signal intensity can be achieved by altering the beam radius or the depth of focus.
( Read Full Article )