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. Author manuscript; available in PMC: 2017 Oct 13.
Published in final edited form as: Ophthalmol Retina. 2017 Apr 5;1(5):435–447. doi: 10.1016/j.oret.2017.01.019

Table 2.

Summary of the OCT Angiography Signal Levels for Thresholded and Unthresholded OCT Angiography Data

Unthresholded OCTA Signal Thresholded OCTA Signal
Case I: No/low blood flow & below-threshold OCT signal High Low
Case II: No/low blood flow & sufficient OCT signal Low Low
Case III: Blood flow & below-threshold OCT signal High Low
Case IV: Blood flow & above-threshold OCT signal High High

OCTA = OCT angiography.

Typically, high OCTA signals are interpreted as indicating the presence of blood flow and low OCTA signals are interpreted as indicating no/low blood flow. Underlined entries indicate cases where this correspondence does not hold. Case I is typical of the vitreous humor, outer nuclear layer, and nonflow regions beneath the retinal pigment epithelium. Case II is typical of the retinal pigment epithelium. Case III is typical of the deeper choroidal vasculature and, in some cases, the choriocapillaris, particularly beneath highly attenuating drusen. Case IV is typical of the retinal vasculature.