Quantitative Comparison Between Optical Coherence Tomography Angiography and Fundus Fluorescein Angiography Images: Effect of Vessel Enhancement

Mochi, Thirumalesh B; Anegondi, Neha; Girish, Molleti; Jayadev, Chaitra; Roy, Abhijit Sinha

doi:10.3928/23258160-20181101-15

Cited by 16 publications

(10 citation statements)

References 14 publications

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“…Therefore, OCTA metrics are not comparable without considering these factors. Nevertheless, some other studies reported similar perfusion density values, using Frangi filter 32 , 33 . Thus far, there is no consensus on which filter and which parameters are optimal for extracting the OCTA metrics.…”

Section: Discussionmentioning

confidence: 68%

Are choriocapillaris flow void features robust to diurnal variations? A swept-source optical coherence tomography angiography (OCTA) study

Lin

Tan

et al. 2020

Sci Rep

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We evaluated the impact of diurnal variation on choroidal and retinal microvasculature and structural measurements using a swept-source optical coherence tomography angiography machine (SS-OCTA; PLEX Elite 9,000, Carl Zeiss Meditec, Inc., Dublin, USA). Fourteen participants who were without ocular diseases underwent SS-OCTA imaging using 3 × 3-mm 2 macular scan pattern on two separate days at five time points. Choriocapillaris flow voids were generated to determine its density (percentage), size (μm) and numbers. Perfusion densities of the large superficial vessels, as well as capillaries on superficial and deep vascular plexuses were generated from retinal angiograms. Subfoveal choroidal and retinal thicknesses were manually measured. Repeated-measures ANOVA was used to investigate the impact of diurnal variation on choroidal and retinal measurements. There was no observable diurnal pattern for any of the flow void features, in terms of the density, size and numbers. There was a significant diurnal pattern observed in the choroidal thickness, where it decreased progressively during the day (P < 0.005). As opposed to sub-foveal choroidal thickness, there does not appear to be significant diurnal variation in choriocapillaris flow voids in normal individuals. This suggests that alterations of choriocapillaris flow deficit seen in pathological eyes will not be confounded by the diurnal fluctuation.

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Section: Discussionmentioning

confidence: 68%

Are choriocapillaris flow void features robust to diurnal variations? A swept-source optical coherence tomography angiography (OCTA) study

Lin

Tan

et al. 2020

Sci Rep

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“…Different global and adaptive thresholding algorithms have been explored for automated segmentation of vasculature in fundus images and, more recently, in OCTA images, including Otsu's method 15 – 17 and multi-scale vesselness filters (e.g., Frangi filter). 22 – 25 However, translation of these thresholding algorithms to grayscale AOSLO perfusion images for the purposes of automatically segmenting retinal vasculature has proven challenging, primarily due to the large variations in contrast, brightness, and background signal that can typically manifest in AOSLO perfusion images. Machine learning techniques, such as convolutional neural networks (CNNs), have been developed for fundus 26 – 28 and OCTA 29 images.…”

Section: Introductionmentioning

confidence: 99%

Automatic Segmentation of Retinal Capillaries in Adaptive Optics Scanning Laser Ophthalmoscope Perfusion Images Using a Convolutional Neural Network

Musial

Queener

Adhikari

et al. 2020

Trans. Vis. Sci. Tech.

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Adaptive optics scanning laser ophthalmoscope (AOSLO) capillary perfusion images can possess large variations in contrast, intensity, and background signal, thereby limiting the use of global or adaptive thresholding techniques for automatic segmentation. We sought to develop an automated approach to segment perfused capillaries in AOSLO images. Methods: 12,979 image patches were extracted from manually segmented AOSLO montages from 14 eyes and used to train a convolutional neural network (CNN) that classified pixels as capillaries, large vessels, background, or image canvas. 1764 patches were extracted from AOSLO montages of four separate subjects, and were segmented manually by two raters (ground truth) and automatically by the CNN, an Otsu's approach, and a Frangi approach. A modified Dice coefficient was created to account for slight spatial differences between the same manually and CNN-segmented capillaries. Results: CNN capillary segmentation had an accuracy (0.94), a Dice coefficient (0.67), and a modified Dice coefficient (0.90) that were significantly higher than other automated approaches (P < 0.05). There were no significant differences in capillary density and mean segment length between manual ground-truth and CNN segmentations (P > 0.05). Conclusions: Close agreement between the CNN and manual segmentations enables robust and objective quantification of perfused capillary metrics. The developed CNN is time and computationally efficient, and distinguishes capillaries from areas containing diffuse background signal and larger underlying vessels. Translational Relevance: This automatic segmentation algorithm greatly increases the efficiency of quantifying AOSLO capillary perfusion images.

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“…Changes in the FAZ area and VD have been reported as important biomarkers for the progression of diabetic retinopathy and retinal vascular diseases and the prognosis of visual acuity [ 27 – 29 ]. These factors are more useful to OCTA than to fluorescein angiography (FAG) [ 30 , 31 ].…”

Section: Discussionmentioning

confidence: 99%

Correlation between macular edema recurrence and macular capillary network destruction in branch retinal vein occlusion

2020

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Background: The aim of this study was to evaluate the correlation between changes in the macular capillary network and macular edema (ME) recurrence with branch retinal vein occlusion (BRVO) using swept-source optical coherence tomography angiography (SS-OCTA). Methods: We reviewed the data for 43 patients with treatment-naïve ME associated with BRVO. Patients who received intravitreal bevacizumab injection were divided into two groups based on ME recurrence at 6 months after edema resolution. The perifoveal capillary morphology and the macular capillary vessel density (VD) were retrospectively analyzed using en face SS-OCTA after ME resolution. Results: The perifoveal capillary ring loss in the superficial capillary plexus (SCP) and deep capillary plexus (DCP) was more common in the ME recurrence group (n = 22) than in the no ME recurrence group (p = 0.047 and p = 0.002). Relative to the findings in the no ME recurrence groups, the destruction of the perifoveal capillary ring was more severe in the DCP (30.0°vs 87.3°, p = 0.001) than in the SCP (17.3°vs 69.5°, p = 0.006) in the ME recurrence group. The hemi-VD disparity between the affected and the unaffected areas in the SCP and DCP showed significant differences (p = 0.031 and p = 0.017), while macular VD showed no differences between the groups. Conclusions: Destruction of the perifoveal capillary ring and hemi-VD disparity could be related to ME recurrence in BRVO. Therefore, these factors may be helpful in predicting ME recurrence.

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Quantitative Comparison Between Optical Coherence Tomography Angiography and Fundus Fluorescein Angiography Images: Effect of Vessel Enhancement

Cited by 16 publications

References 14 publications

Are choriocapillaris flow void features robust to diurnal variations? A swept-source optical coherence tomography angiography (OCTA) study

Are choriocapillaris flow void features robust to diurnal variations? A swept-source optical coherence tomography angiography (OCTA) study

Automatic Segmentation of Retinal Capillaries in Adaptive Optics Scanning Laser Ophthalmoscope Perfusion Images Using a Convolutional Neural Network

Correlation between macular edema recurrence and macular capillary network destruction in branch retinal vein occlusion

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