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Anoush Shahidzadeh, Alice Yon Kim, Hassan A Aziz, Mary K Durbin, Carmen A Puliafito, Amir H Kashani; Widefield Swept-Source Optical Coherence Tomography Angiography. Invest. Ophthalmol. Vis. Sci. 2016;57(12):445.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the benefits and limitations of wide-angle swept source optical coherence tomography angiography (SS-OCTA) 12x12mm scans compared to spectral domain OCTA (SD-OCTA) 6x6mm scans.
Patients with possible extramacular retinal pathology were recruited and imaged at the USC Eye Institute with prototype Cirrus SD-OCTA and SS-OCTA devices (Carl Zeiss Meditec, Dublin, CA). The SD-OCTA used a wavelength of 840 nm with scan speed of 68kHz, whereas the SS-OCTA used a wavelength of 1060nm with scan speed of 100kHz. Both devices had an axial resolution of 5um and lateral resolution of 15um. At least one 6x6mm SD-OCTA scan and one 12x12mm SS-OCTA scan centered on the fovea were taken for each study eye. Average acquisition time, quality of images, and ability to detect extramacular pathologies were assessed and compared within each scan frame. The structural en face images accompanying each OCTA scan were used to validate the quality of scans chosen for comparisons.
Nine subjects (11 eyes) with the following retinal pathologies were included in this study: ERM, diabetic retinopathy, macular edema, vitreomacular traction, dry age related macular degeneration, optic neuritis, hypertensive retinopathy, and vitreous hemorrhage. Seven eyes demonstrated significant extramacular pathology in the 12x12mm SS-OCTA scans that was not visible in 6x6mm SD-OCTA scans. Average acquisition times for SD- and SS-OCTA images were approximately 4 seconds and 5-12 seconds, respectively, depending on fixation. Overall, there was no qualitative difference in scanning performance or patient experience between either device. In addition, overall quality of angiographic information in SS-OCTA images was qualitatively similar to SD-OCTA.
SS-OCTA systems can provide additional angiographic information in a quick, non-invasive, and convenient way analogous to SD-OCTA systems without significant compromise in performance. Larger fields of view allow for easier identification of extramacular pathologies that may be clinically relevant.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
6x6mm SD- and 12x12mm SS-OCTA images of the left eye of a 38-year-old male with proliferative diabetic retinopathy and macular edema previously treated with laser and injections. (A) SD- and (B) SS-OCTA scans centered around the fovea and there structural en face images below (C, D respectively). The yellow box in (B) shows the area encompassed by the 6x6mm SD-OCTA scan.
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