Aims: Angiographic ectasias and aneurysms in stented segments have been associated with late stent thrombosis. Using optical coherence tomography (OCT), some stented segments show coronary evaginations reminiscent of ectasias. The purpose of this study was to explore, using computational fluid-dynamic (CFD) simulations, whether OCT-detected coronary evaginations can induce local changes in blood flow. Methods and results: OCT-detected evaginations are defined as outward bulges in the luminal vessel contour between struts, with the depth of the bulge exceeding the actual strut thickness. Evaginations can be characterised cross ectionally by depth and along the stented segment by total length. Assuming an ellipsoid ...
Quantitative analysis of optical coherence tomography volumes is an important tool for both clinicians and researchers. Until now, most work has focused on segmentation of the intraretinal cell layers, but the segmentation of pathological datasets remains challenging. We propose the application of random forest to detect the locations of drusen in the retinal pigment epithelium. This is an important step for further analysis of optical coherence tomography data, for segmentation or otherwise. The presented combination of Bruch’s Membrane segmentation with subsequent sampling around the retinal pigment epithelium is a way to quickly compute discriminative features for classification. The proposed ...
With improvements in acquisition speed and quality, the amount of medical image data to be screened by clinicians is starting to become challenging in the daily clinical practice. To quickly visualize and find abnormalities in medical images, we propose a new method combining segmentation algorithms with statistical shape models. A statistical shape model built from a healthy population will have a close fit in healthy regions. The model will however not fit to morphological abnormalities often present in the areas of pathologies. Using the residual fitting error of the statistical shape model, pathologies can be visualized very quickly. This idea ...
Objectives This study sought to assess stent strut coverage, malapposition, protrusion, and coronary evaginations as markers of healing 5 years after implantation of sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES), by optical coherence tomography (OCT). Background Early-generation drug-eluting stents have been shown to delay vascular healing. Methods A total of 88 event-free patients with 1 randomly selected lesion were suitable for final OCT analysis 5 years after drug-eluting stent implantation. The analytical approach was based on a hierarchical Bayesian random-effects model. Results OCT analysis was performed at 5 years in 41 SES lesions with 6,380 struts, and in 47 ...
Advances of fundus images have resulted in better understanding of age-related macular degeneration (AMD) in the past.
Purpose. Hyperreflective foci (HFs) are observable within the neurosensory retina in diabetic macular edema (DME) using spectral domain optical coherence tomography (SD-OCT). HFs have also been seen in wet age-related macular degeneration (AMD), although the origin is still unknown; however, they reduced significantly during anti-VEGF (vascular endothelial growth factor) therapy, and their baseline amount seemed to correlate with treatment success. In this study the behavior of HFs was evaluated during anti-VEGF therapy for DME. Methods. Fifty-one patients (mean age: 67 years) underwent SD-OCT before and one month after one anti-VEGF injection (ranibizumab: n = 30; bevacizumab: n = 21). The HFs were ...
Purpose:Hyperreflective foci (HF) are observable within the neurosensory retina in diabetic macular edema (DME) using spectral domain optical coherence tomography (SD-OCT). The HF behaviour was evaluated during Anti-VEGF therapy in DME. Methods: Fifty-one patients (mean age: 67 years) underwent SD-OCT (Heidelberg engineering, Germany) before and one month after one Anti-VEGF injection (Ranibizumab: n=30; Bevacizumab: n=21). The amount of HFs were semi-quantitatively counted, assigned to 3 groups (A: SDPs n=1-10; B: n=11-20; C: n>20) and correlated to the course of visual acuity and foveal thickness (paired t-test). Additionally the baseline HbA1c was categorized and correlated ...
Aims: To demonstrate the feasibility and potential usefulness of an offline fusion of matched optical coherence tomography (OCT) and intravascular ultrasound (IVUS)/virtual histology (IVUS-VH) images.
Background—The vascular tissue reaction to acute incomplete stent apposition (ISA) is not well known. The aim of this study was to characterize the vascular response to acute ISA in vivo and to look for predictors of incomplete healing. Methods and Results—Optical coherence tomography studies of 66 stents of different designs, implanted in 43 patients enrolled in 3 randomized trials, were analyzed sequentially after implantation and at 6 to 13 months. Seventy-eight segments with acute ISA were identified in 36 of the patients and matched with the follow-up study by use of fiduciary landmarks. The morphological pattern of healing ...
Objective To quantify the circumferential healing process at 6 and 12 months following scaffold implantation. Background The healing process following stent implantation consists of tissue growing on the top of and in the space between each strut. With the ABSORB bioresorbable vascular scaffold (BVS), the outer circumference of the scaffold is detectable by optical coherence tomography (OCT), allowing a more accurate and complete evaluation of the intra-scaffold neointima. Methods A total of 58 patients (59 lesions), who received an ABSORB BVS 1.1 implantation and a subsequent OCT investigation at 6 (n = 28 patients/lesions) or 12 (n = 30 patients ...
Aims: To analyse and to compare the changes in the various optical coherence tomography (OCT), echo-genicity intravascular ultrasound virtual histology (VH) of the everolimus-eluting bioresorbable scaffold (ABSORB) degradation parameters during the first 12 months after ASOERB implantation.
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