ZEISS Angioplex™ Spectral Domain Optical Coherence Tomography Angiography: Technical Aspects

PURPOSE. To evaluate the microvascular changes in eyes with RP quantitatively using optical coherence tomography angiography (OCTA) and to determine whether the correlations between these indices and the severity of RP are significant.METHODS. This was a retrospective, observational study. The medical records of 53 RP patients and 46 controls were reviewed. The OCTA images were obtained with the Cirrus 5000 with Angioplex, and an automated program was used to analyze the microvascular patterns. The perfusion density (PD) and vessel length density (VLD) were used as indices of the microvascular density, whereas the vessel diameter index (VDI) was used as a measure of the caliber of the vessels. The width of the ellipsoid zone (EZ) in the OCT images and the mean deviation (MD) of the Humphry Field Analyzer (HFA) were used to determine the severity of the RP. Student's t-tests and Spearman's correlation tests were used.RESULTS. Both the PD and VLD in the superficial and deep plexuses and the whole retina were significantly reduced, and the VDI was significantly increased in RP patients compared with the corresponding values of the controls (P < 0.001). Spearman's rank tests indicated the RP severity was significantly correlated with the PD and VLD in all three layers (P < 0.001, r ranging from 0.50 to 0.87) and significantly correlated with VDI in the deep and the whole retina (P < 0.001, ranging from À0.64 to À0.73).CONCLUSIONS. Quantitative changes in the microvascular density might be useful for examining the pathophysiology of RP.

Section: 13mentioning

confidence: 99%

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confidence: 99%

Quantification of Macular Microvascular Changes in Patients With Retinitis Pigmentosa Using Optical Coherence Tomography Angiography

Inooka

Ueno

Kominami

et al. 2018

“…1 OCT-A relies on the principle that erythrocytes flowing in blood vessels are the only moving structure across co-registered sequential B-scans and, therefore, they can be used as a motion contrast to differentiate vessels from static tissues. 1 Based on this assumption, several algorithms have been developed by many instruments including complex optical microangiography (OMAG) for Zeiss devices (Angioplex and PLEX Elite 9000; Carl Zeiss Meditec, Inc., Dublin, CA, USA), 2,3 split spectrum amplitude decorrelation angiography algorithm (SSADA) for RTVue XR Avanti (Optovue Inc., Fremont, CA, USA), 4 OCT angiography ratio analyses (OCTARA) for DRI OCT Triton (Topcon, Tokyo, Japan), 5 and full-spectrum amplitude decorrelation algorithm (FSADA) for Heidelberg (Spectralis; HRA Heidelberg, Heidelberg, Germany). 6 All these machines provide en face angiogram images, which can be postprocessed in order to obtain quantitative parameters, such as foveal avascular zone (FAZ) area and vessel density.…”

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confidence: 99%

Macular Perfusion Parameters in Different Angiocube Sizes: Does The Size Matter in Quantitative Optical Coherence Tomography Angiography?

Rabiolo

Gelormini

Marchese

et al. 2018

PURPOSE. To investigate the macular quantitative parameters interchangeability of three different optical coherence tomography angiography (OCT-A) angiocubes (i.e., 3 3 3, 6 3 6, and 12 3 12 mm) on healthy subjects and patients affected by diabetic retinopathy (DR) and to assess the interrater reliability of such indices across the different scan protocols. METHODS.Retrospective study involving 20 eyes of healthy subjects and 20 eyes with DR. All eyes underwent swept-source OCT-A with 3 3 3-, 6 3 6-, and 12 3 12-mm angiocubes centered on the fovea. Foveal avascular zone (FAZ) area and vessel density on 3 3 3-, 6 3 6-, and 12 3 12-mm macular scans were calculated by three independent operators at all retina, superficial, deep, and choriocapillary vascular layers. Interchangeability and interrater reliabilities were estimated using intraclass correlation coefficient (ICC).RESULTS. Interscan reproducibility of FAZ area was very strong (ICC > 0.85) at every plexus. On the contrary, vessel density values significantly varied across different scan sizes (ICC < 0.51). Intrascan interrater reliability was high for all retina and superficial FAZ areas, while it was satisfactory at deep capillary plexus only for 3 3 3-mm scan.CONCLUSIONS. FAZ area at all plexuses is a robust parameter even if calculated on angiocubes with different size. However, interrater reliability is higher when measured in smaller scans. Conversely, vessel density results depend on the size of angiocube, although their interrater reliability is extremely high. Studies involving OCT-A should take into consideration that scan size may influence macular perfusion parameters and interrater reliability.

“…8,9 OCTA therefore enables detailed and reproducible images of the retinal microvasculature networks to be obtained with a high level of resolution. 10 The foveal avascular zone (FAZ) is the round, capillary-free zone within the macula. Measurements of FAZ size (area and perimeter) using OCTA have been shown to be highly reproducible in patients with microcirculatory deficiency involving the macula, such as diabetic retinopathy, as well as in healthy individuals.…”

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confidence: 99%

An Optical Coherence Tomography Angiography Study of the Relationship Between Foveal Avascular Zone Size and Retinal Vessel Density

Kwon

Choi²,

Shin

et al. 2018

PURPOSE. To assess the relationship between the size of the foveal avascular zone (FAZ; area and perimeter) and vessel density (VD) at various retinal regions using optical coherence tomography angiography (OCTA) in patients with open-angle glaucoma (OAG).METHODS. In this retrospective cross-sectional study, OAG eyes were grouped according to the presence/absence of central visual field (CVF) defects. A control group of normal eyes was also included. OCTA images were obtained from the optic nerve (4.5 3 4.5 mm 2 ) and macular (3 3 3 mm 2 ) area, in which VDs were measured in the circumpapilla, parafovea, and fovea regions. Partial correlation analyses between FAZ parameters representing size and VDs at different retinal regions were performed. The correlation between FAZ parameters and macular ganglion cell-inner plexiform layer thickness (mGCIPLT) and CVF mean sensitivity (MS) was also assessed. For spatial correspondence, correlations between FAZ parameters and corresponding VD, mGCIPLT, and CVF-MS measurements were assessed at each hemiretina. RESULTS.A total of 126 OAG eyes and 40 controls were reviewed. Overall, FAZ parameters showed statistically significant correlations with VDs measured at the fovea, parafovea, and circumpapilla (FAZ area: r ¼ À0.603, À0.385, À0.256; P < 0.001, < 0.001, and 0.003, respectively). These correlations were observed regardless of the presence of CVF defects (all P < 0.05). FAZ size showed significant spatial correlations with VD, mGCIPLT, and CVF-MS measurements at each hemiretina.CONCLUSIONS. OCTA-derived FAZ area and perimeter showed statistically significant correlations with VDs measured at various retinal locations with spatial correspondence in OAG.