OCT Signs of Early Atrophy in Age-Related Macular Degeneration: Interreader Agreement: Classification of Atrophy Meetings Report 6.

PURPOSE: To determine the interreader agreement for incomplete retinal pigment epithelium (RPE) and outer retinal atrophy (iRORA) and complete RPE and outer retinal atrophy (cRORA) and their related features in age-related macular degeneration (AMD). DESIGN: Interreader agreement study. PARTICIPANTS: Twelve readers from 6 reading centers. METHODS: After formal training, readers qualitatively assessed 60 OCT B-scans from 60 eyes with AMD for 9 individual features associated with early atrophy and performed 7 different annotations to quantify the spatial extent of OCT features within regions of interest. The qualitative and quantitative features were used to derive the presence of iRORA and cRORA and also in an exploratory analysis to examine if agreement could be improved using different combinations of features to define OCT atrophy. MAIN OUTCOME MEASURES: Interreader agreement based on Gwet's first-order agreement coefficient (AC1) for qualitatively graded OCT features and classification of iRORA and cRORA, and smallest real difference (SRD) for quantitatively graded OCT features. RESULTS: Substantial or better interreader agreement was observed for all qualitatively graded OCT features associated with atrophy (AC1 = 0.63-0.87), except for RPE attenuation (AC1 = 0.46) and disruption (AC1 = 0.26). The lowest SRD for the quantitatively graded horizontal features was observed for the zone of choroidal hypertransmission (± 190.8 μm). Moderate agreement was found for a 3-category classification of no atrophy, iRORA, and cRORA (AC1 = 0.53). Exploratory analyses suggested a significantly higher level of agreement for a 3-category classification using (1) no atrophy; (2) presence of inner nuclear layer and outer plexiform layer subsidence, or a hyporeflective wedge-shaped band, as a less severe atrophic grade; and (3) the latter plus an additional requirement of choroidal hypertransmission of 250 μm or more for a more severe atrophic grade (AC1 = 0.68; P = 0.013). CONCLUSIONS: Assessment of iRORA and cRORA, and most of their associated features, can be performed relatively consistently and robustly. A refined combination of features to define early atrophy could further improve interreader agreement

Comparison of wide field optical coherence tomography angiography with extended field imaging and fluorescein angiography in retinal vascular disorders.

PurposeTo compare swept source OCTA device, with and without the extended field imaging (EFI) technique, to standard fluorescein angiography (FA) in the clinical practice.MethodsConsecutive patients with vascular disorder patients underwent FA with 55-degree lens (Spectralis Heidelberg Engineering, Heidelberg, Germany) and OCTA with the prototype PlexElite (Carl Zeiss Meditec, Dublin, CA) using a 12 mm x 12 mm volume scan pattern centered on the fovea and a prototype of + 20.00-diopter designed specifically by Zeiss. The imaging methods were compared for visible field of view, extension of non-perfused areas, presence and number of neovessels, vessel density (VD) and fractal dimension (FD).ResultsForty-three eyes of 27 patients were included. The mean extension ratio of EFI SS-OCTA compared to SS-OCTA without EFI and FA were 1.97 ± 0.02 and 0.85 ± 0.01. The mean extension of non-perfused areas with EFI SS-OCTA (34.22 ± 33.4 mm2) was significantly higher than SS-OCTA without EFI (20.46 ± 18.70 mm2), and with FA (27.55 ± 4.4 mm2). The mean VD and FD of EFI SS-OCTA were significantly different compared to SS-OCT without EFI.ConclusionsEFI SS-OCTA captured larger areas than SS-OCTA without EFI and FA. OCTA in a single shot is able to obtain more information of the retina without the use of montage techniques. Despite the determination of retinal ischemia seems to be easier and more accurate using EFI SS-OCTA, FA offers more details of the perfusion status of the retina

Objective scoring of transformed foci in BALB/c 3T3 cell transformation assay by statistical image descriptors

In vitro cell transformation assays (CTAs) have been shown to model important stages of in vivo carcinogenesis and have the potential to predict carcinogenicity in humans. Advantages of CTAs are their ability of revealing both genotoxic and non-genotoxic carcinogens while reducing both experimental costs and the number of animals used. The endpoint of the CTA is foci formation, and requires classification under light microscopy based on morphology. Thus current limitations for the wide adoption of the assay partially depend on a fair degree of subjectivity in foci scoring. An objective evaluation may be obtained after separating foci from background monolayer in the digital image, and quantifying values of statistical descriptors which are selected to capture eye-scored morphological features. The aim of this study was to develop statistical descriptors to be applied to transformed foci of BALB/c 3T3, which cover foci size, multilayering and invasive cell growth into the background monolayer. Proposed descriptors were applied to a database of 407 foci images to explore the numerical features, and to illustrate open problems and potential solutions.JRC.I.5-Systems Toxicolog

Optical Coherence Tomography Angiography of the Choriocapillaris in Age-Related Macular Degeneration

The advent of optical coherence tomography angiography (OCTA) has allowed for remarkable advancements in our understanding of the role of the choriocapillaris in age-related macular degeneration (AMD). As a relatively new imaging modality, techniques to analyze and quantify choriocapillaris images are still evolving. Quantification of the choriocapillaris requires careful consideration of many factors, including the type of OCTA device, segmentation of the choriocapillaris slab, image processing techniques, and thresholding method. OCTA imaging shows that the choriocapillaris is impaired in intermediate non-neovascular AMD, and the severity of impairment may predict the advancement of disease. In advanced atrophic AMD, the choriocapillaris is severely impaired underneath the area of geographic atrophy, and the level of impairment surrounding the lesion predicts the rate of atrophy enlargement. Macular neovascularization can be readily identified and classified using OCTA, but it is still unclear if neovascularization features with OCTA can predict the lesion’s level of activity. The choriocapillaris surrounding macular neovascularization is impaired while the more peripheral choriocapillaris is spared, implying that choriocapillaris disruption may drive neovascularization growth. With continued innovation in OCTA image acquisition and analysis methods, advancement in clinical applications and pathophysiologic discoveries in AMD are set to follow

Optic disc pit associated with an unusual outer retinal hole and nasal peripheral retinoschisis

PURPOSE To document a peculiar case of optic disc pit-associated maculopathy (ODP-M) with extensive nasal retinoschisis with lamellar outer retinal hole. METHODS Case report. PATIENT A 41 year-old woman presented to the eye clinic complaining of new photopsias and enlargement of the blind spot in the left eye. Uncorrected visual acuity was 20/20 in both eyes. Fundus examination of the left eye revealed an anomalous appearing optic nerve with a gray oval depression at the temporal margin of the disk consistent with an ODP. RESULTS Optical coherence tomography confirmed the presence of the pit and demonstrated outer plexiform layer schisis superonasal to the fovea as well as extensive inner and outer retinal schisis nasal to the nerve extending to the equator. A large lamellar outer retinal hole was noted nasal to the disk without associated retinal detachment. The vitreous appeared to be attached over the nasal retina. DISCUSSION Multimodal imaging revealed an unusual ODP associated retinopathy with dramatically more extensive retinoschisis and a lamellar outer retinal hole nasal to the nerve despite the temporal location of the pit. Although the precise pathophysiologic mechanisms are not fully understood, forces associated with the vitreo-retinal adhesion may have contributed to the distribution of the schisis in this case

Relationship between increasing concentrations of two carcinogens and statistical image descriptors of foci morphology in the cell transformation assay

Cell Transformation Assays (CTAs) have long been proposed for the identification of chemical carcinogenicity potential. The endpoint of these in vitro assays is represented by the phenotypic alterations in cultured cells, which are characterized by the change from the non-transformed to the transformed phenotype. Despite the wide fields of application and the numerous advantages of CTAs, their use in regulatory toxicology has been limited in part due to concerns about the subjective nature of visual scoring, i.e. the step in which transformed colonies or foci are evaluated through morphological features. An objective evaluation of morphological features has been previously obtained through automated digital processing of foci images to extract the value of three statistical image descriptors. In this study a further potential of the CTA using BALB/c 3T3 cells is addressed by analysing the effect of increasing concentrations of two known carcinogens, benzo[a]pyrene and NiCl2, with different modes of action on foci morphology. The main result of our quantitative evaluation shows that the concentration of the considered carcinogens has an effect on foci morphology that is statistically significant for the mean of two among the three selected descriptors. Statistical significance also corresponds to visual relevance. The statistical analysis of variations in foci morphology due to concentration allowed to quantify morphological changes that can be visually appreciated but not precisely determined. Therefore, it has the potential of providing new quantitative parameters in CTAs, and of exploiting all the information encoded in foci.JRC.F.3-Chemicals Safety and Alternative Method

A comprehensive statistical classifier of foci in the cell transformation assay for carcinogenicity testing

The identification of the carcinogenic risk of chemicals is currently mainly based on animal studies. The in vitro Cell Transformation Assays (CTAs) are a promising alternative to be considered in an integrated approach. CTAs measure the induction of foci of transformed cells. CTAs model key stages of the in vivo neoplastic process and are able to detect both genotoxic and some non-genotoxic compounds, being the only in vitro method able to deal with the latter. Despite their favorable features, CTAs can be further improved, especially reducing the possible subjectivity arising from the last phase of the protocol, namely visual scoring of foci using coded morphological features. By taking advantage of digital image analysis, the aim of our work is to translate morphological features into statistical descriptors of foci images, and to use them to mimic the classification performances of the visual scorer to discriminate between transformed and non-transformed foci. Here we present a classifier based on five descriptors trained on a dataset of 1364 foci, obtained with different compounds and concentrations. Our classifier showed accuracy, sensitivity and specificity equal to 0.77 and an area under the curve (AUC) of 0.84. The presented classifier outperforms a previously published model.JRC.F.3-Chemicals Safety and Alternative Method

Characterisation of the vascular anterior surface of type 1 macular neovascularisation after anti-VEGF therapy

Background To evaluate whether the status of vasculature at the top of type 1 macular neovascularisation (MNV) could function as mediator of the observed protective effect against the development of complete retinal pigment epithelial and outer retinal atrophy (cRORA). Methods In consecutive treatment-naive patients, the vasculature at the anterior surface of the MNV was isolated using a slab designed to extract the most superficial vascular portion of the MNV lesion showing a choriocapillaris (CC)-like structure which we termed the 'neo-CC'. The ratio between the neo-CC area (isolated using this custom slab) and the MNV area (isolated using the standard outer retina-CC slab) at baseline and at last follow-up was evaluated. Results Forty-four eyes from 44 patients were included. 20 showed cRORA by the final follow-up (median 23 months), whereas 24 did not progress to atrophy (median 23.5 months). The proportion of MNV with neo-CC at the anterior surface was significantly lower in eyes which progressed to cRORA compared with those which did not. The multivariate regression showed that a lower proportion of neo-CC coverage over the MNV was associated with an increased odds for cRORA development. Conclusions More extensive coverage of neo-CC is associated with a lower likelihood of development of macular atrophy in eyes receiving antivascular endothelial growth factor therapy, suggesting the protective effect of a type 1 MNV may be mediated by the development of a neo-CC and may provide insights into the biological significance of MNV as a response mechanism in eyes with age-related macular degeneration