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Artifacts in OCT Angiography :fire:, How is motion detected (Principles…
Artifacts in OCT Angiography
:fire:
How is motion detected
Principles
Scan a region repeatedly
Moving structures (Blood flow): More change
Stationary tissue: Little change
Voxel
Volume + Pixel
Image variations: Noise
Strong signal: Flow easy to detect
Weak signal: ?Noise
THRESHOLD needed
Speckles or
Intensity Decorrelation
Reflecting points
Secondary spherical wave front
Contructive and Destructive interference
SPECKLES
Stationary tissue: the same
Moving structures
Speckles changes
Faster area of flow correlates with greater changes:
beam size, blood vessels, not necessarily linear
Amplitude decorrelation
reflection strength change among pixels
Phase Variance
