Navegando por Palavras-chave "nascent geographic atrophy"

Agora exibindo 1 - 2 de 2
  • Nenhuma Miniatura disponível
    Item
    Somente Metadadados
    Swept source OCT angiography reveals choriocapillaris alterations in eyes with nascent geographic atrophy and drusen-associated atrophy
    (Lippincott Williams & Wilkins, 2016) Moult, Eric M.; Waheed, Nadia K.; Novais, Eduardo A.; Choi, Woojhon; Lee, Byungkun; Ploner, Stefan B.; Cole, Emily D.; Louzada, Ricardo Nogueira [UNIFESP]; Lu, Chen D.; Rosenfeld, Philip J.; Duker, Jay S.; Fujimoto, James G.
    Purpose: To investigate choriocapillaris (CC) alteration in patients with nascent geographic atrophy (nGA) and/or drusen-associated geographic atrophy (DAGA) using swept-source optical coherence tomography angiography (OCTA). Methods: A 1,050-nm wavelength, 400 kHz A-scan rate swept-source optical coherence tomography prototype was used to perform volumetric swept-source optical coherence tomography angiography over 6 mm x 6 mm fields of view in patients with nGA and/or DAGA. The resulting optical coherence tomography (OCT) and OCTA data were analyzed using a combination of en face and cross-sectional techniques. Variable interscan time analysis (VISTA) was used to differentiate CC flow impairment from complete CC atrophy. Results: A total of 7 eyes from 6 patients (mean age: 73.8 +/- 5.7 years) were scanned. Seven areas of nGA and three areas of DAGA were identified. Analysis of cross-sectional OCT and OCTA images identified focal alterations of the CC underlying all seven areas of nGA and all three areas of DAGA. En face OCTA analysis of the CC revealed diffuse CC alterations in all eyes. Variable interscan time analysis processing suggested that the observed CC flow alterations predominantly corresponded to flow impairment rather than complete CC atrophy. Conclusion: The OCTA imaging of the CC revealed focal CC flow impairment associated with areas of nGA and DAGA, as well as diffuse CC flow impairment throughout the imaged field. En face OCT analysis should prove useful for understanding the pathogenesis of nGA and DAGA and for identifying the formation of nGA and DAGA as endpoints in therapeutic trials.
  • Nenhuma Miniatura disponível
    Item
    Somente Metadadados
    Toward Quantitative Optical Coherence Tomography Angiography Visualizing Blood Flow Speeds in Ocular Pathology Using Variable Interscan Time Analysis
    (Lippincott Williams & Wilkins, 2016) Ploner, Stefan B.; Moult, Eric M.; Choi, Woojhon; Waheed, Nadia K.; Lee, Byungkun; Novais, Eduardo Amorim [UNIFESP]; Cole, Emily D.; Potsaid, Benjamin; Husvogt, Lennart; Schottenhamml, Julia; Maier, Andreas; Rosenfeld, Philip J.; Duker, Jay S.; Hornegger, Joachim; Fujimoto, James G.
    Purpose: Currently available optical coherence tomography angiography systems provide information about blood flux but only limited information about blood flow speed. The authors develop a method for mapping the previously proposed variable interscan time analysis (VISTA) algorithm into a color display that encodes relative blood flow speed. Methods: Optical coherence tomography angiography was performed with a 1,050 nm, 400 kHz A-scan rate, swept source optical coherence tomography system using a 5 repeated B-scan protocol. Variable interscan time analysis was used to compute the optical coherence tomography angiography signal from B-scan pairs having 1.5 millisecond and 3.0 milliseconds interscan times. The resulting VISTA data were then mapped to a color space for display. Results: The authors evaluated the VISTA visualization algorithm in normal eyes (n = 2), nonproliferative diabetic retinopathy eyes (n = 6), proliferative diabetic retinopathy eyes (n = 3), geographic atrophy eyes (n = 4), and exudative age-related macular degeneration eyes (n = 2). All eyes showed blood flow speed variations, and all eyes with pathology showed abnormal blood flow speeds compared with controls. Conclusion: The authors developed a novel method for mapping VISTA into a color display, allowing visualization of relative blood flow speeds. The method was found useful, in a small case series, for visualizing blood flow speeds in a variety of ocular diseases and serves as a step toward quantitative optical coherence tomography angiography.