Optical coherence tomography angiography artifacts in retinal pigment epithelial detachment.

OBJECTIVE: To describe optical coherence tomography angiography (OCTA) reflectance artifacts secondary to retinal pigment epithelial detachment (RPED). DESIGN: Retrospective review. METHODS: Four eyes from 4 subjects were included. Three presented with RPED and 1 eye was a normal control. Two eyes diagnosed with RPED and the normal eye were evaluated using en face OCTA centred at the fovea acquired using the RTVue XR Avanti (Optovue Inc). In the third eye with RPED, OCTA imaging was performed using a CIRRUS 5000 prototype modified to do OCTA imaging on a spectral domain OCT platform provided by Carl Zeiss Meditec, Inc. The segmented OCTA angiograms were overlaid to determine if the flow patterns seen at the edge of the RPEDs were due to reflectance from the inner retinal vessels, also known as "decorrelation tails." RESULTS: OCTA projection artifacts were noted when segmentation lines intersected with the boundary of the RPED. The overlaid segmented OCTA from the 3 RPED eyes imaged using each system revealed the same vasculature pattern at the edges of the RPED as that of the inner retina, demonstrating the "decorrelation tails" artifact, which caused the RPED to appear as a bright ring on the segmented OCTA. CONCLUSIONS: OCTA images are susceptible to various known artifacts. This series describes the impact of the projection artifact seen at the edges of an RPED that simulates appearance of flow but is actually due to reflectance of the inner retinal vasculature on the RPED.

Optical Coherence Tomography Angiography in Nonarteritic Anterior Ischemic Optic Neuropathy.

BACKGROUND: Optical coherence tomography angiography (OCTA) has demonstrated good utility in qualitative analysis of retinal and choroidal vasculature and therefore may be relevant in the diagnostic and treatment efforts surrounding nonarteritic anterior ischemic optic neuropathy (NAION). METHODS: Retrospective, cross-sectional study of 10 eyes of 9 patients with a previous or new diagnosis of NAION that received imaging with OCTA between November 2015 and February 2016. Two independent readers qualitatively analyzed the retinal peripapillary capillaries (RPC) and peripapillary choriocapillaris (PCC) for flow impairment. Findings were compared with automated visual field and structural optical coherence tomography (OCT) studies. RESULTS: Flow impairment seen on OCTA in the RPC corresponded to structural OCT deficits of the retinal nerve fiber layer (RNFL) and ganglion cell layer complex (GCC) in 80% and 100% of eyes, respectively, and to automated visual field deficits in 90% of eyes. Flow impairment seen on OCTA in the PCC corresponded to structural OCT deficits of the RNFL and GCC in 70% and 80% of eyes, respectively, and to visual field deficits in 60%-80% of eyes. CONCLUSIONS: OCTA can noninvasively visualize microvascular flow impairment in patients with NAION.

CLINICAL TRIAL ENDPOINTS FOR OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY IN NEOVASCULAR AGE-RELATED MACULAR DEGENERATION.

PURPOSE: To describe qualitative and quantitative optical coherence tomography (OCT) angiography (OCTA) parameters for choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD) and their applicability as potential clinical trial endpoints. METHODS: A review of current literature related to the topic of OCTA and AMD. RESULTS: There are a number of promising OCTA parameters that can be used to diagnose the presence of CNV and to monitor the activity and progression of the lesion, pre- and post-treatment morphological characteristics, CNV dimensions, and automated quantitative parameters such as vessel density. CONCLUSION: The OCTA parameters described in this review have promise for the future development of clinical trial endpoints, but require further validation before they can be widely used.

AN AUTOMATIC, INTERCAPILLARY AREA-BASED ALGORITHM FOR QUANTIFYING DIABETES-RELATED CAPILLARY DROPOUT USING OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY.

PURPOSE: To develop a robust, sensitive, and fully automatic algorithm to quantify diabetes-related capillary dropout using optical coherence tomography (OCT) angiography (OCTA). METHODS: A 1,050-nm wavelength, 400 kHz A-scan rate swept-source optical coherence tomography prototype was used to perform volumetric optical coherence tomography angiography imaging over 3 mm × 3 mm fields in normal controls (n = 5), patients with diabetes without diabetic retinopathy (DR) (n = 7), patients with nonproliferative diabetic retinopathy (NPDR) (n = 9), and patients with proliferative diabetic retinopathy (PDR) (n = 5); for each patient, one eye was imaged. A fully automatic algorithm to quantify intercapillary areas was developed. RESULTS: Of the 26 evaluated eyes, the segmentation was successful in 22 eyes (85%). The mean values of the 10 and 20 largest intercapillary areas, either including or excluding the foveal avascular zone, showed a consistent trend of increasing size from normal control eyes, to eyes with diabetic retinopathy but without diabetic retinopathy, to nonproliferative diabetic retinopathy eyes, and finally to PDR eyes. CONCLUSION: Optical coherence tomography angiography-based screening and monitoring of patients with diabetic retinopathy is critically dependent on automated vessel analysis. The algorithm presented was able to automatically extract an intercapillary area-based metric in patients having various stages of diabetic retinopathy. Intercapillary area-based approaches are likely more sensitive to early stage capillary dropout than vascular density-based methods.

Choroidal thickness in older patients with central serous chorioretinopathy.

BACKGROUND: To investigate the choroidal thickness in older patients with central serous chorioretinopathy (CSCR) compared to age-matched normal subjects. METHODS: Fifteen patients (30 eyes) with CSCR, all aged ≥60 years, and 21 age-matched normal subjects (21 eyes) underwent high-definition raster scanning using SD-OCT. Both eyes from CSCR patients were included in the analysis. The eyes in patients with CSCR were divided into two groups: active CSCR (17 eyes) if there was foveal-involving subretinal fluid and inactive contralateral eye group (13 eyes). Choroidal thickness was measured from the posterior edge of the retinal pigment epithelium to the choroidal-scleral junction at 500 µm intervals up to 2500 µm temporal and nasal to the fovea (11 locations). RESULTS: The mean age of the patients with CSCR was 68.87 ± 6.83 years (mean ± standard deviation). Reliable measurements of choroidal thickness were obtainable in 70.6 % of eyes examined. The choroid was statistically significantly thicker in eyes with both active CSCR (P < 0.001) and inactive contralateral eyes (P < 0.01) when compared to normal age-matched eyes. The subfoveal choroid was 95 µm (P < 0.01) thicker in eyes with active CSCR (338.05 ± 31.42 µm) compared with normal eyes (243.05 ± 13.39 µm). The subfoveal choroid thickness in the inactive contralateral eyes was numerically greater than normal, and it was not statistically significantly thicker compared to the normal eyes (difference-55.68 µm, P > 0.05). CONCLUSION: Choroid in older patients with active CSCR was thicker than the choroid in age-matched normal eyes. It is important to consider CSCR as a differential diagnosis of serous retinal detachment in elderly patients with thickened choroid and to consider SD-OCT as an imaging modality by which to evaluate the choroidal thickness.

Effect of intravitreal anti-VEGF on choroidal thickness in patients with diabetic macular edema using spectral domain OCT.

PURPOSE: To evaluate choroidal thickness (CT) using spectral domain optical coherence tomography (SD-OCT) imaging at baseline and 6 months after intravitreal anti-vascular endothelial growth factor (anti-VEGF) treatment in patients with diabetic macular edema (DME). METHODS: A retrospective chart review was performed to identify patients with DME who underwent intravitreal injection of anti-VEGF (bevacizumab or ranibizumab) in a pro re nata (PRN) regimen. Subfoveal choroidal thickness was compared between values obtained at baseline and at 6-month follow-up visits. RESULTS: Thirty-nine eyes (15 females, 24 males) from 39 patients were enrolled (mean age, 62.43 ± 8.7 years; range, 44-79 years). Twenty-three and 16 eyes were treated with ranibizumab and bevacizumab respectively. The mean number of anti-VEGF injections was 2.28 ± 1.27 (range, 1-5). Mean nasal, subfoveal, and temporal choroidal thickness (CT) measurements at baseline were 234.10 ± 8.63 µm, 246.89 ± 8.94 µm, and 238.12 ± 8.20 µm, respectively, and those at 6 months post-treatment were 210.46 ± 8.00 µm, 215.66 ± 8.29 µm, and 212.43 ± 8.14 µm, respectively. Significant differences in CT were observed between baseline and the 6-month follow-up at all measured points (p=0.0327). CONCLUSIONS: Over a 6-month period, the use of intravitreal anti-VEGF was associated with significant thinning of the choroid in patients with DME. The clinical significance of a thinner choroid in DME is currently unknown; however, it may contribute to long-term adverse effects on choroidal and retinal function, representing an area requiring future investigation.

Effect of intravitreal anti-VEGF on choroidal thickness in patients with diabetic macular edema using spectral domain OCT / Efeito de injeção intravítrea na espessura de coroide em pacientes com edema macular diabético utilizando OCT de domínio espectral

ABSTRACT Purpose: To evaluate choroidal thickness (CT) using spectral domain optical coherence tomography (SD-OCT) imaging at baseline and 6 months after intravitreal anti-vascular endothelial growth factor (anti-VEGF) treatment in patients with diabetic macular edema (DME). Methods: A retrospective chart review was performed to identify patients with DME who underwent intravitreal injection of anti-VEGF (bevacizumab or ranibizumab) in a pro re nata (PRN) regimen. Subfoveal choroidal thickness was compared between values obtained at baseline and at 6-month follow-up visits. Results: Thirty-nine eyes (15 females, 24 males) from 39 patients were enrolled (mean age, 62.43 ± 8.7 years; range, 44-79 years). Twenty-three and 16 eyes were treated with ranibizumab and bevacizumab respectively. The mean number of anti-VEGF injections was 2.28 ± 1.27 (range, 1-5). Mean nasal, subfoveal, and temporal choroidal thickness (CT) measurements at baseline were 234.10 ± 8.63 µm, 246.89 ± 8.94 µm, and 238.12 ± 8.20 µm, respectively, and those at 6 months post-treatment were 210.46 ± 8.00 µm, 215.66 ± 8.29 µm, and 212.43 ± 8.14 µm, respectively. Significant differences in CT were observed between baseline and the 6-month follow-up at all measured points (p=0.0327). Conclusions: Over a 6-month period, the use of intravitreal anti-VEGF was associated with significant thinning of the choroid in patients with DME. The clinical significance of a thinner choroid in DME is currently unknown; however, it may contribute to long-term adverse effects on choroidal and retinal function, representing an area requiring future investigation.

RESUMO Objetivos: Avaliar a espessura de coroide pré-tratamento e após 6 meses da injeção intravítrea de anti-fator de crescimento vascular endotelial (anti-VEGF) em pacientes com edema macular diabético (EMD), utilizando a tomografia de coerência óptica de domínio espectral (SD-OCT). Métodos: Análise retrospectiva, com revisão de prontuários, foi realizada para identificação de pacientes submetidos a tratamento com injeções intravítreas de anti-VEGF, no regime pro re nata, para tratamento de EMD. As medidas da espessura de coroide pré-tratamento foi comparada com as medidas após acompanhamento de 6 meses. Resultados: Trinta e nove olhos de 39 pacientes (15 femininos, 24 masculinos) foram incluídos, com idade média de 62,43 ± 8,7 anos (variando de 44-79 anos). Trinta e três olhos foram tratados com ranibizumab e 18 com bevacizumab. O número médio de injeções de anti-VEGF foi 2,28 ± 1,27 (variando de 1-5). A medida média pré-tratamento da espessura de coroide nasal, subfoveal e temporal foi 234,10 ± 8,63 µm, 246,89 ± 8,94 µm e 238,12± 8,20 µm, respectivamente. Após acompanhamento de 6 meses as medidas médias da espessura de coroide foram 210,46 ± 8,00 µm, 215,66 ± 8,29 µm e 212,43 ± 8,14 µm. A diferença entre as medidas médias pré e pós tratamento foi estatisticamente significante (p=0,0327) em todos os pontos medidos. Conclusão: Após um período de 6 meses, o uso de injeções intravítreas de anti-VEGF foi associado com diminuição significante da espessura de coroide nos pacientes com EMD. O significado clínico de uma coroide mais fina nos pacientes com EMD é desconhecido mas pode causar eventos adversos a longo prazo para função da coroide e retina, representando uma área para futura investigações.

Choroidal Neovascularization Analyzed on Ultrahigh-Speed Swept-Source Optical Coherence Tomography Angiography Compared to Spectral-Domain Optical Coherence Tomography Angiography.

PURPOSE: To compare visualization of choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD) using an ultrahigh-speed swept-source (SS) optical coherence tomography angiography (OCTA) prototype vs a spectral-domain (SD) OCTA device. DESIGN: Comparative analysis of diagnostic instruments. METHODS: Patients were prospectively recruited to be imaged on SD OCT and SS OCT devices on the same day. The SD OCT device employed is the RTVue Avanti (Optovue, Inc, Fremont, California, USA), which operates at ∼840 nm wavelength and 70 000 A-scans/second. The SS OCT device used is an ultrahigh-speed long-wavelength prototype that operates at ∼1050 nm wavelength and 400 000 A-scans/second. Two observers independently measured the CNV area on OCTA en face images from the 2 devices. The nonparametric Wilcoxon signed rank test was used to compare area measurements and P values of <.05 were considered statistically significant. RESULTS: Fourteen eyes from 13 patients were enrolled. The CNV in 11 eyes (78.6%) were classified as type 1, 2 eyes (14.3%) as type 2, and 1 eye (7.1%) as mixed type. Total CNV area measured using SS OCT and SD OCT 3 mm × 3 mm OCTA were 0.949 ± 1.168 mm(2) and 0.340 ± 0.301 mm(2), respectively (P = .001). For the 6 mm × 6 mm OCTA the total CNV area using SS OCT and SD OCT were 1.218 ± 1.284 mm(2) and 0.604 ± 0.597 mm(2), respectively (P = .0019). The field of view did not significantly affect the measured CNV area (P = .19 and P = .18 for SS OCT and SD OCT, respectively). CONCLUSION: SS OCTA yielded significantly larger CNV areas than SD OCTA. It is possible that SS OCTA is better able to demarcate the full extent of CNV vasculature.