Implementation and application of a Monte Carlo model for an in vivo micro computed tomography system.

Micro computed tomography (µCT) scanners are used to create high-resolution images and to quantify properties of the scanned objects. While modern µCT scanners benefit from the cone beam geometry, they are compromised by scatter radiation. This work aims to develop a Monte Carlo (MC) model of a µCT scanner in order to characterize the scatter radiation in the detector plane.

Outcome of intravitreal dexamethasone implant for the treatment of ranibizumab-resistant macular edema secondary to retinal vein occlusion.

To assess the effect of intravitreal dexamethasone implant (Ozurdex) for the treatment of macular edema secondary to retinal vein occlusion (RVO) resistant to repeated intravitreal ranibizumab injection. Retrospective review of 11 patients (11 eyes) with ranibizumab-resistant macular edema secondary to RVO. Macular edema was considered refractory to ranibizumab if no change of the pattern of macular fluid on optical coherence tomography and no change of best-corrected visual acuity (BCVA) was observed after at least three consecutive monthly injections, excluding the loading dose.

20 g PPV with indocyanine green-assisted ILM peeling versus 23 g PPV with brilliant blue G-assisted ILM peeling for epiretinal membrane.

To compare the anatomical and visual outcomes of 20 gauge (g) pars plana vitrectomy (PPV) with indocyanine green (ICG)-assisted internal limiting membrane (ILM) peeling and 23 g PPV with brilliant blue G (BBG)-assisted ILM peeling for idiopathic epiretinal membrane (ERM). 38 eyes of 38 patients with idiopathic ERM were included. They were divided in two groups: group 1 (18 eyes) underwent 20 g PPV with ICG-assisted ILM peeling and group 2 (20 eyes) 23 g PPV with BBG-assisted ILM peeling.

Diagnostic Accuracy of Quantitative and Qualitative Phase-Contrast Imaging for the ex Vivo Characterization of Human Coronary Atherosclerotic Plaques.

Purpose: To investigate the accuracy of x-ray grating interferometry phase-contrast (PC) imaging for the characterization of human coronary artery plaque.

Materials And Methods: PC and conventional absorption computed tomographic (CT) imaging was performed ex vivo in this institutional review board-approved study in 40 human coronary artery segments by using a synchrotron radiation source. Qualitative analyses and calculations of image quality (McNemar test), plaque components (McNemar test), and plaque classification (Cohen κ test) according to the American Heart Association classification were performed in 38 plaques detected at histopathologic examination (reference standard).

Multiple scattering tomography.

Multiple scattering represents a challenge for numerous modern tomographic imaging techniques. In this Letter, we derive an appropriate line integral that allows for the tomographic reconstruction of angular resolved scattering distributions, even in the presence of multiple scattering. The line integral is applicable to a wide range of imaging techniques utilizing various kinds of probes.

Combining Monte Carlo methods with coherent wave optics for the simulation of phase-sensitive X-ray imaging.

Phase-sensitive X-ray imaging shows a high sensitivity towards electron density variations, making it well suited for imaging of soft tissue matter. However, there are still open questions about the details of the image formation process. Here, a framework for numerical simulations of phase-sensitive X-ray imaging is presented, which takes both particle- and wave-like properties of X-rays into consideration.

Living-engineered valves for transcatheter venous valve repair.

Background: Chronic venous insufficiency (CVI) represents a major global health problem with increasing prevalence and morbidity. CVI is due to an incompetence of the venous valves, which causes venous reflux and distal venous hypertension. Several studies have focused on the replacement of diseased venous valves using xeno- and allogenic transplants, so far with moderate success due to immunologic and thromboembolic complications.

Off-the-shelf human decellularized tissue-engineered heart valves in a non-human primate model.

Heart valve tissue engineering based on decellularized xenogenic or allogenic starter matrices has shown promising first clinical results. However, the availability of healthy homologous donor valves is limited and xenogenic materials are associated with infectious and immunologic risks. To address such limitations, biodegradable synthetic materials have been successfully used for the creation of living autologous tissue-engineered heart valves (TEHVs) in vitro.

Engineering of living autologous human umbilical cord cell-based septal occluder membranes using composite PGA-P4HB matrices.

Interventional closure of intracardiac wall defects using occluder devices has evolved as a highly attractive treatment option. However, incomplete and delayed healing reactions often result in a major risk of residual defects, thromboembolism, or device fractures. Biodegradable living tissue engineered occluder membranes (TEOMs) could provide autologous thromboresistant implants with growth and remodeling capacities.

Ocular photodynamic therapy--standard applications and new indications. Part 2. Review of the literature and personal experience.

Photodynamic therapy (PDT) has become a well-established treatment for vascular forms of age-related macular degeneration (AMD). The implementation of evidence-based medicine principles into the treatment regimen of AMD seems to be immensly important, since AMD continues to be the most frequent cause of blindness among patients older than 65 years in industrialized countries. Numerous randomized prospective studies demonstrated high levels of evidence for the efficacy of various treatment approaches such as laser photocoagulation, PDT, subretinal surgery or novel anti-angiogenic drugs [Arch Ophthalmol 2006;124:597-599].

Accessory optical device for the Heidelberg retina angiograph (HRA classic) to perform angiography of the vitreous cavity and the anterior eye segment.

The Heidelberg retina angiograph (HRA) classic enables fluorescein angiography (FA) and indocyanine green angiography (ICG-A) of the retina and choroid. The goal of this study was to design an accessory device to adapt the HRA classic for application on structures anterior to the retina. The optical device consisted of a cylindrical two-piece plastic frame holding a magnifying lens commonly used with the indirect ophthalmoscope.

Ocular photodynamic therapy--standard applications and new indications (part 1). Review of the literature and personal experience.

Ocular photodynamic therapy (PDT) was introduced as a novel treatment for neovascular forms of age-related macular degeneration and choroidal neovascularization (CNV) secondary to pathologic myopia in the mid/end 1990s. The current treatment recommendations are based on the results of two large, prospective, multicenter, randomized clinical trials (Treatment of Age-Related Macular Degeneration with Photodynamic Therapy and Verteporfin in Photodynamic Therapy Studies) and thousands of patients have been treated worldwide over the last years. Meanwhile, PDT has been performed in several other ocular pathologies with some remarkable results, however, with most reports being case reports and small case series without statistical significance.

Current treatment modalities for exudative retinal hamartomas secondary to tuberous sclerosis: review of the literature.

Background: Retinal hamartoma is a common finding in tuberous sclerosis, but the symptomatic changes of this lesion have rarely been described. This evidence-based review evaluated the incidence of symptomatic retinal hamartoma and compared possible treatment modalities.

Methods: We carried out a review of the literature using MEDLINE.

Retinal branch artery occlusion following injection of hyaluronic acid (Restylane).

The authors report a retinal branch artery occlusion occurring after facial injection of a dermal filler. The superior temporal artery showed occlusion due to a clearly visible long and fragmented embolus suggestive of gel and clearly distinguishable from calcific or cholesterol emboli. The authors suppose that hyaluronic acid gel was embolized in the patient.

Effect of photodynamic therapy on the function of the outer blood-retinal barrier in an in vitro model.

Background: Photodynamic therapy (PDT) is a well established clinical treatment for age-related macular degeneration (AMD), and comprises intravenous injection of verteporfin and subsequent application of a non-thermal laser beam to the area of AMD to induce selective vascular occlusion. Since there is evidence that PDT may cause outer blood-retinal barrier (BRB) breakdown and possibly RPE cell alteration, we investigated the effect of PDT on the BRB function of the RPE in an in vitro model.

Methods: Twenty-one monolayers of human RPE cells were cultured on semipermeable membranes until a stable barrier function was achieved as determined by transepithelial electrical resistance (TER) and sodium fluorescein permeability.

Autofluorescence and angiographic findings of retinal astrocytic hamartomas in tuberous sclerosis.

Objective: To describe fundus autofluorescence (AF), fluorescein angiography (FA) and indocyanine green angiography (ICGA) in different types of retinal astrocytic hamartomas in tuberous sclerosis (Morbus Bourneville-Pringle).

Methods: Two eyes with 8 lesions, i.e.

Transient serous retinal detachment in classic and occult choroidal neovascularization after photodynamic therapy.

Purpose: To quantify transient serous retinal detachment in classic and occult choroidal neovascularization (CNV) after photodynamic therapy (PDT).

Design: Prospective consecutive case series.

Methods: Consecutive patients with classic and occult CNV were examined by optical coherence tomography before PDT and at 2 and 7 days after PDT.

Skew deviation: a precursor to basilar artery thrombosis.

The aim of this study was to describe skew deviation and vertical nystagmus as the initial signs for basilar artery thrombosis, a life-threatening disease. A 51-year-old woman complained of vertical diplopia for more than 20 h. A computed tomography of the brain was normal, but subsequently the patient developed additional symptoms including nausea, ventilation problems (dyspnoea) and somnolence.

Diminished transforming growth factor beta2 production leads to increased expression of a profibrotic procollagen alpha2 type I messenger RNA variant in embryonic fibroblasts of UCD-200 chickens, a model for systemic sclerosis.

Objective: A procollagen alpha2(I) messenger RNA (mRNA) variant, with a 115-bp band and an expected band of 180 bp, was found to be increased during early, acute scleroderma-like disease in UCD-200 chickens. The present study investigated the influence of cytokines on the expression of these 2 proalpha2(I) mRNA variants.

Methods: Embryonic fibroblasts of UCD-200 chickens (UCD-200-CEF) and normal white leghorns (NWL-CEF) were grown in 3-dimensional collagen gels.

Photodynamic therapy and indocyanine green guided feeder vessel photocoagulation of choroidal neovascularization secondary to choroid rupture after blunt trauma.

Purpose: To describe photodynamic therapy (PDT) and additional indocyanine green (ICG) guided feeder vessel photocoagulation as a treatment of choroidal neovascularization (CNV) secondary to choroidal rupture in case of blunt head trauma.

Design: Interventional case report.

Methods: A 61-year-old woman developed subfoveal CNV originating from a choroid tear 8 years after blunt head trauma.