Characterization of microvascular tortuosity in retinal vein occlusion utilizing optical coherence tomography angiography

Abstract

We investigated the characteristics of microvessel tortuosity in branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO) and their associations with visual outcomes using optical coherence tomography angiography (OCTA). Thirty-four BRVO and 21 CRVO patients and 31 healthy subjects were included. From OCTA, the branch number (BN), mean branch length (BL), mean Euclidean length (EL), vessel density (VD) and vessel tortuosity (VT) were quantified. In BRVO eyes, compared with that in the controls, the affected area of the deep capillary plexus (DCP) showed a decreased BN and VD, an increased BL, and unchanged VT. The nonaffected area of the DCP showed decreases in BN, VD and VT. The affected area of the superficial capillary plexus (SCP) showed higher VT. In CRVO eyes, the DCP showed a lower BN, VD and VT, while the SCP showed a lower BN and greater BL and EL. Improved visual acuity (VA) after 1 year in BRVO eyes was associated with decreases in BN, BL, VD and VT in the affected area in the DCP and lower VT in the nonaffected area of the SCP; in CRVO eyes, improved VA was associated with a higher BL and EL in the DCP. VT, BL, and EL may be new microvascular markers associated with changes in VA in BRVO and CRVO.

Increased capillary stalling is associated with endothelial glycocalyx loss in subcortical vascular dementia

“…After equalization, vessels were segmented using the Weka trainable segmentation plugin in Fiji software (Supplementary Figure 1 C). [43][44][45][46] Shadows from large pial vessels were manually removed from the image. The vascular areas of the large pial vessels were measured.…”

Swept-source optical coherence tomography angiography metrics of retinal ischaemic perivascular lesions in patients being evaluated for carotid artery stenosis and controls

“…VLD was then calculated for each en face image as ((length of vessels in pixels)/(surface area in pixels 2 ))×1024 pixels/6 mm, giving units of per mm, as reported previously 17 18. VT was similarly examined with Fiji’s ‘Analyze Skeleton’ function by dividing the summed total length of all skeletonized blood vessels in pixels by the summed Euclidean distances between consecutive branch points and/or endpoints in pixels, giving a dimensionless ratio as previously described 19. The FAZ was excluded from all VLD and VT calculations.…”

“… 17 18 VT was similarly examined with Fiji’s ‘Analyze Skeleton’ function by dividing the summed total length of all skeletonized blood vessels in pixels by the summed Euclidean distances between consecutive branch points and/or endpoints in pixels, giving a dimensionless ratio as previously described. 19 The FAZ was excluded from all VLD and VT calculations. SCP and DCP en face images were also segmented in Fiji into grids of 32-pixel × 32-pixel squares, from which VLD and VT were calculated as described above.…”

Optical Coherence Tomography Angiography: Clinical Utility and Future Directions

“…18,89,90 These changes include a reduction in foveal and parafoveal vessel densities, increased areas of nonperfusion, the engorgement of capillary networks, increased vascular tortuosity, increased collateral vessels, and the development of telangiectasias. [91][92][93][94] Notably, the best-corrected visual acuity (VA) in eyes with retinal vein occlusion has been shown to be negatively correlated with the area of the superficial foveal avascular zone and positively correlated with the parafoveal vessel density. 89,95 In a case series of 144 eyes with retinal vein occlusion comparing the capacity of OCTA vs FA in delineating areas of retinal capillary nonperfusion, OCTA was found to be more precise.…”