The Utility of Frame Averaging for Automated Algorithms in Analyzing Retinal Vascular Biomarkers in AngioVue OCTA

Schmidt, Taly Gilat; Linderman, Rachel E; Strampe, Margaret R.; Chui, Toco Y. P.; Rosen, Richard B.; Carroll, Joseph

doi:10.1167/tvst.8.1.10

Cited by 17 publications

(19 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…OCT angiography is a recently developed noninvasive alternative to IVFA which utilizes erythrocyte motion as intrinsic contrast to produce high-resolution images of the retinal microvasculature [10,[24][25][26][27][28]. Using averaged OCT angiography images, perfused retinal capillaries appear as discrete and continuous, allowing precise delineation of FAZ border without the noise of background fluorescence or the temporal decay of the fluorescence signal in patients with diabetic retinopathy [29][30][31]. En face OCT reflectance images can also reveal capillaries not seen on OCT angiography by utilizing the reflective microstructural information which includes both the perfused and nonperfused capillaries [32,33].…”

Section: Introductionmentioning

confidence: 99%

Within-subject assessment of foveal avascular zone enlargement in different stages of diabetic retinopathy using en face OCT reflectance and OCT angiography

Lynch¹,

Romo²,

Linderman³

et al. 2018

Biomed. Opt. Express

Self Cite

View full text Add to dashboard Cite

Enlargement of the foveal avascular zone (FAZ) due to progressive capillary nonperfusion is associated with visual deterioration in patients with diabetic retinopathy. The FAZ area has long been considered an important clinical marker of advancing retinopathy. However, a large body of literature shows that the FAZ area varies considerably in healthy eyes, resulting in substantial overlap between controls and diabetics, thus reducing its discriminatory value. In this study, within-subject FAZ area enlargement was obtained by the comparison of the structural FAZ area to the functional FAZ area using simultaneouslyacquired, corresponding en face OCT reflectance and OCT angiography images. Our study suggests that en face OCT reflectance images provide useful anatomic baselines of structural FAZ morphology prior to the onset of disease. Measurements of within-subject FAZ area enlargement appear to be a more sensitive method for identifying the onset of diabetic retinopathy as compared to using OCT angiographic measurements of FAZ alone.

show abstract

Section: Introductionmentioning

confidence: 99%

Within-subject assessment of foveal avascular zone enlargement in different stages of diabetic retinopathy using en face OCT reflectance and OCT angiography

Lynch¹,

Romo²,

Linderman³

et al. 2018

Biomed. Opt. Express

Self Cite

View full text Add to dashboard Cite

show abstract

“…53 This tradeoff can be compensated for via montaging multiple smaller high-quality images or by utilizing frame averaging with larger images to improve the signalto-noise ratio. 4,[36][37][38][39] Whereas montaging and averaging are feasible in a research setting, they have not yet reached widespread use -this can be remedied with software advances. Future studies may be able to identify the optimal scan size that gives reliable measures of vessel morphometry without sacrificing the scan area.…”

Section: Discussionmentioning

confidence: 99%

“…The area and perimeter were converted from pixels to absolute retinal measurements (in millimeters) by multiplying by the real scale of that image. 36 The real scale of each image was calculated as follows: Acircularity is a unitless metric generated from estimates of the FAZ area and FAZ perimeter, and was calculated as follows:…”

Section: Quantitative Retinal Vasculature Analysis Foveal Avascular Zmentioning

confidence: 99%

Assessing the Influence of OCT-A Device and Scan Size on Retinal Vascular Metrics

Kraker

Omoba

Cava

et al. 2020

Trans. Vis. Sci. Tech.

Self Cite

View full text Add to dashboard Cite

The purpose of this study was to investigate the effect of device and scan size on quantitative optical coherence tomography angiography (OCT-A) metrics. Methods: The 3 × 3 mm scans from Optovue AngioVue and Zeiss AngioPlex systems were included for 18 eyes of 18 subjects without ocular pathology. The foveal avascular zone (FAZ) was segmented manually by two observers, from which estimates of FAZ area (using both the nominal image scale and the axial length corrected image scale) and acircularity were derived. Three scan sizes (3 mm, 6 mm HD, and 8 mm) from the AngioVue system were included for 15 eyes of 15 subjects without ocular pathology. For each subject, larger image sizes were resized to the same resolution as 3 × 3 mm scans, aligned, then cropped to a common area. FAZ area, FAZ acircularity, average and total parafoveal intercapillary area, vessel density, and vessel end points were computed. Results: Between the devices used here, there were no significant differences in FAZ acircularity (P = 0.88) or FAZ area using scaled (P = 0.11) or unscaled images (P = 0.069). Although there was no significant difference in FAZ area across scan sizes (P = 0.30), vessel morphometry metrics were all significantly influenced by scan size. Conclusions: The scan devices and sizes used here do not affect FAZ area measures derived from manual segmentations. In contrast, vessel morphometry metrics are affected by scan size. As individual differences in axial length induce differences in absolute scan size, extreme care should be taken when interpreting metrics of vessel morphometry, both between and within OCT-A devices. Translational Relevance: A better characterization of the confounds surrounding OCT-A retinal vasculature metrics can lead to improved application of these metrics as biomarkers for retinal and systemic diseases.

show abstract

“… 35 In addition, we used a single OCTA image to evaluate the FAZ, which sometimes are imperfect compared to using the multiple averaging thecnique. 37 – 39 Microcapillaries, which constitute the FAZ, sometimes could not be detected by OCTA. Therefore the FAZ area might be overestimated, especially in cases with abnormality, although we carefully checked and modified FAZ segmentation in all OCTA images.…”

Section: Discussionmentioning

confidence: 99%

Visual Acuity Recovery After Macular Hole Closure Associated With Foveal Avascular Zone Change

Tsuboi

Fukutomi

Sasajima

et al. 2020

Trans. Vis. Sci. Tech.

View full text Add to dashboard Cite

To evaluate changes in the foveal avascular zone (FAZ) area during the postoperative period of macular hole (MH) surgery using the optical coherence tomography angiography (OCTA) and to investigate its relationship to visual acuity (VA). Methods: Consecutive unilateral MH patients who underwent successful MH closure with at least a six-month observation period were studied retrospectively. To evaluate the FAZ area, OCTA images were obtained at the preoperative visit, the first postoperative visit, and the six-month visit. Main outcome measures were postoperative FAZ change and its relationship to VA change after MH closure. Results: Fifty-one cases were studied. The FAZ area was 0.42 ± 0.11 mm 2 at the preoperative visit, 0.25 ± 0.091 mm 2 at the first postoperative visit and 0.31 ± 0.11 mm 2 at the six-month visit. FAZ area at the first postoperative visit was significantly smaller (P < 0.0001) than at the preoperative visit. FAZ area at the six-month visit was significantly greater (P < 0.0001) than at the first postoperative visit, but still significantly smaller (P = 0.0002) compared to the normal fellow eye. The postoperative FAZ area enlargement from the first postoperative visit to the six-month visit was significantly correlated with the postoperative VA recovery (P = 0.0322) and the postoperative photoreceptor reconstruction (P = 0.0213). Conclusions: The FAZ area once decreases along with MH closure; it thereafter increases toward the normal value over time. The postoperative FAZ change was correlated with the VA recovery. Translational Relevance: This study suggests that the postoperative FAZ area enlargement might be a potential biomarker indicating foveal reconstruction after MH closure.

show abstract

The Utility of Frame Averaging for Automated Algorithms in Analyzing Retinal Vascular Biomarkers in AngioVue OCTA

Cited by 17 publications

References 43 publications

Within-subject assessment of foveal avascular zone enlargement in different stages of diabetic retinopathy using en face OCT reflectance and OCT angiography

Within-subject assessment of foveal avascular zone enlargement in different stages of diabetic retinopathy using en face OCT reflectance and OCT angiography

Assessing the Influence of OCT-A Device and Scan Size on Retinal Vascular Metrics

Visual Acuity Recovery After Macular Hole Closure Associated With Foveal Avascular Zone Change

Contact Info

Product

Resources

About