Dataset Information

Prevalence and Severity of Artifacts in Optical Coherence Tomographic Angiograms.

ABSTRACT: Importance:Artifacts can affect optical coherence tomographic angiography (OCTA) images and may be associated with misinterpretation of OCT scans in both clinical trials and clinical settings. Objectives:To identify the prevalence and type of artifacts in OCTA images associated with quantitative output and to analyze the role of proprietary quality indices in establishing image reliability. Design, Setting, and Participants:This cross-sectional study evaluated baseline OCTA images acquired in multicenter clinical trials and submitted to the Fundus Photograph Reading Center in Madison, Wisconsin, between January 1, 2016, and December 31, 2018. Images were captured using the 3 mm?×?3 mm and/or 6 mm?×?6 mm scan protocol with commercially available OCTA systems. Artifacts, including decentration, segmentation error, movement, blink, refraction shift, defocus, shadow, Z offset, tilt, and projection, were given a severity grade based on involvement of cross-sectional OCT and area of OCT grid affected. Main Outcomes and Measures:Prevalence and severity of OCTA artifacts and area under the receiver operating characteristic curve (AUC) of quality indices with image reliability. Results:A total of 406 OCTA images from 234 eyes were included in this study, of which 221 (54.4%) were 6 mm?×?6 mm scans and 185 (45.6%) were 3 mm?×?3 mm scans. At least 1 artifact was documented in 395 images (97.3%). Severe artifacts associated with the reliability of quantitative outputs were found in 217 images (53.5%). Shadow (26.9% [109 images]), defocus (20.9% [85 images]), and movement (16.0% [65 images]) were the 3 most prevalent artifacts. Prevalence of artifacts did not vary with the imaging system used or with the scan protocol; however, the type of artifacts varied. Commercially recommended quality index thresholds had an AUC of 0.80 to 0.83, sensitivity of 97% to 99%, and specificity of 37% to 41% for reliable images. Conclusions and Relevance:Findings from this study suggest that artifacts associated with quantitative outputs on commercially available OCTA devices are highly prevalent and that identifying common artifacts may require correlation with the angiogram and cross-sectional OCT scans. Knowledge of these artifacts and their implications for OCTA indices appears to be warranted for more accurate interpretation of OCTA images.

SUBMITTER: Holmen IC

PROVIDER: S-EPMC6902206 | biostudies-literature | 2020 Feb

REPOSITORIES: biostudies-literature

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Prevalence and Severity of Artifacts in Optical Coherence Tomographic Angiograms.

Holmen Ian C IC Konda Sri Meghana SM Pak Jeong W JW McDaniel Kyle W KW Blodi Barbara B Stepien Kimberly E KE Domalpally Amitha A

JAMA ophthalmology 20200201 2

<h4>Importance</h4>Artifacts can affect optical coherence tomographic angiography (OCTA) images and may be associated with misinterpretation of OCT scans in both clinical trials and clinical settings.<h4>Objectives</h4>To identify the prevalence and type of artifacts in OCTA images associated with quantitative output and to analyze the role of proprietary quality indices in establishing image reliability.<h4>Design, setting, and participants</h4>This cross-sectional study evaluated baseline OCTA ...[more]

PMID: 31804666

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Project description:OBJECTIVE:To analyze quality and frequency of OCTA artifacts and to evaluate their impact on the interpretability of OCTA images. DESIGN:75 patients with diabetic retinopathy (DR), retinal artery occlusion (RAO), retinal vein occlusion (RVO), or neovascular age-related macular degeneration (nAMD) and healthy controls were enrolled in this cross-sectional study in the outpatient department of a tertiary eye care center. METHODS:All participants underwent an OCTA examination (spectral domain OCT Cirrus 5000 equipped with the AngioPlex module). OCTA scans were analyzed independently by two experienced ophthalmologists. Frequency of various artifacts for the entire OCTA scan and for different segmentation layers and the grading of OCTA interpretability were investigated. RESULTS:The analysis of 75 eyes of 38 women and 37 men between 24 and 94 years were included. Six eyes had no retinal disease, 19 eyes had nAMD, 16 had DR, 19 eyes had RVO, and 15 eyes showed RAO. A macular edema (ME) was present in 40 of the diseased eyes. Projection artifacts occurred in all eyes in any structure below the superficial retinal vessel layer, segmentation and motion artifacts were found in 55% (41/75) and 49% (37/75) of eyes, respectively. Other artifacts occurred less frequently. Segmentation artifacts were significantly more frequent in diseased than in healthy eyes (p<0.01). Qualitative assessment of OCTA images was graded as excellent in 65% and sufficient in 25% of cases, adding up to 91% images deemed acceptable for examination. Presence of ME was associated with a significantly poorer interpretability (p<0.01). CONCLUSION AND RELEVANCE:Various artifacts appear at different frequencies in OCTA images. Nevertheless, a qualitative assessment of the OCTA images is almost always possible. Good knowledge of possible artifacts and critical analysis of the complete OCTA dataset are essential for correct clinical interpretation and determining a precise clinical diagnosis.

Project description:ImportanceBiomarker testing for asymptomatic, preclinical Alzheimer disease (AD) is invasive and expensive. Optical coherence tomographic angiography (OCTA) is a noninvasive technique that allows analysis of retinal and microvascular anatomy, which is altered in early-stage AD.ObjectiveTo determine whether OCTA can detect early retinal alterations in cognitively normal study participants with preclinical AD diagnosed by criterion standard biomarker testing.Design, setting, and participantsThis case-control study included 32 participants recruited from the Charles F. and Joanne Knight Alzheimer Disease Research Center, Washington University in St Louis, St Louis, Missouri. Results of extensive neuropsychometric testing determined that all participants were cognitively normal. Participants underwent positron emission tomography and/or cerebral spinal fluid testing to determine biomarker status. Individuals with prior ophthalmic disease, media opacity, diabetes, or uncontrolled hypertension were excluded. Data were collected from July 1, 2016, through September 30, 2017, and analyzed from July 30, 2016, through December 31, 2017.Main outcomes and measuresAutomated measurements of retinal nerve fiber layer thickness, ganglion cell layer thickness, inner and outer foveal thickness, vascular density, macular volume, and foveal avascular zone were collected using an OCTA system from both eyes of all participants. Separate model III analyses of covariance were used to analyze individual data outcome.ResultsFifty-eight eyes from 30 participants (53% female; mean [SD] age, 74.5 [5.6] years; age range, 62-92 years) were included in the analysis. One participant was African American and 29 were white. Fourteen participants had biomarkers positive for AD and thus a diagnosis of preclinical AD (mean [SD] age, 73.5 [4.7] years); 16 without biomarkers served as a control group (mean [SD] age, 75.4 [6.6] years). The foveal avascular zone was increased in the biomarker-positive group compared with controls (mean [SD], 0.364 [0.095] vs 0.275 [0.060] mm2; P = .002). Mean (SD) inner foveal thickness was decreased in the biomarker-positive group (66.0 [9.9] vs 75.4 [10.6] μm; P = .03).Conclusions and relevanceThis study suggests that cognitively healthy individuals with preclinical AD have retinal microvascular abnormalities in addition to architectural alterations and that these changes occur at earlier stages of AD than has previously been demonstrated. Longitudinal studies in larger cohorts are needed to determine whether this finding has value in identifying preclinical AD.

Project description:Purpose The primary objective of this study was to compare placenta growth factor (PlGF) levels in the serum and vitreous of diabetic retinopathy (DR) patients to non-diabetic controls. Additionally, the study aimed to establish associations between serum and vitreous PlGF concentrations and to examine the correlation between vitreous PlGF in DR patients and morphological parameters. Methods This study included serum and vitreous samples from 38 patients, including 21 patients with DR and 17 non-diabetic controls. The control group included non-diabetic patients with rhegmatogenous retinal detachment with retinal tears secondary to posterior vitreous detachment or trauma. PlGF levels were quantified in vitreous and serum samples using an enzyme-linked immunosorbent assay (ELISA). Optical coherence tomography (OCT) scans from DR patients were evaluated to measure the central retinal thickness (CRT) and macular volume (MV). Results DR patients had significantly higher mean vitreous PlGF levels compared to non-DR patients (70.0±39.2 vs. 46.47±9.7 pg/mL, p-value=0.004). However, no significant increase in mean serum PlGF levels was observed in DR patients (p-value=0.232). Within the DR group, proliferative DR (PDR) patients presented significantly higher vitreous PlGF levels than non-PDR (NPDR) patients (76.5±41.0 vs. 42.5±5.0 pg/mL, p-value=0.009). There was no association between serum and vitreous PlGF levels. The correlation between vitreous PlGF levels and morphological parameters was rsp=0.175, p-value=0.488 for CRT, and rsp=0.288, p-value=0.262 for MV. Conclusion This study emphasizes the important role of PlGF in neovascularization, specifically highlighting its overexpression exclusively in vitreous from PDR patients. The observed increase in PlGF levels may be indicative of disease severity. The lack of correlation between vitreous and serum PlGF levels suggests a potential dissociation between intravitreal and systemic PlGF synthesis. Consequently, targeting PlGF in therapeutic approaches may offer an additional strategy for ocular pathologies with a neovascular component.

Project description:PurposeTo use projection-resolved optical coherence tomographic angiography (PR-OCTA) to characterize the microvascular changes in 3 distinct retinal plexuses in retinitis pigmentosa (RP) patients.DesignProspective cross-sectional study.MethodsA commercial 70-kHz spectral-domain optical coherence tomography (OCT) system was used to acquire 6-mm macular scans from RP patients and age-matched healthy participants at a tertiary academic center. Blood flow was detected using a commercial version of split-spectrum amplitude-decorrelation angiography (SSADA) algorithm. The PR-OCTA algorithm was used to suppress projection artifacts and resolve microvasculature in 3 plexuses around the macula. Vessel density was calculated from en face OCTA of the parafoveal and perifoveal regions in each of the 3 plexuses, as well as the all-plexus inner retinal slab. Inner and outer retinal thicknesses were measured form structural OCT scans. Generalized estimating equations and Spearman's rank correlation statistical methods were used.ResultsForty-four eyes from 26 RP patients and 34 eyes from 26 healthy subjects were included. Significant reduction in vessel density was detected in the perifovea but not the parafovea of inner retinal slab of RP patients (P = .001 and P = .56, respectively) compared to controls. We also found deeper retinal plexuses (intermediate and deep capillary plexuses, ICP and DCP) were primarily damaged by RP, compared to superficial vascular complex (SVC). Significant thickening of the inner retina and thinning of the outer retina were also observed. Strong correlation was found between the vessel density in the perifoveal ICP and DCP and outer retinal thickness in RP patients with no history of cystoid macular edema.ConclusionsPR-OCTA enables the detection of microvascular changes in the perifoveal regions of the ICP and DCP in RP, with relative sparing of the SVC. OCT and OCTA parameters might be able to provide better understanding of the pathophysiology of the disease, as well as monitoring disease progression and the response to experimental treatments.

Dataset Information

Prevalence and Severity of Artifacts in Optical Coherence Tomographic Angiograms.

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Prevalence and Severity of Artifacts in Optical Coherence Tomographic Angiograms.

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