Zeiss CIRRUS HD-OCT 500, User Manual

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Criteria for Image Acceptance
2660021169012 Rev. A 2017-12 CIRRUS HD-OCT User Manual
7-8
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Decorrelation Tails
Decorrelation Tails: Frequently seen as bright shadows of more superficial vessels that
appear in posterior layers, decorrelation tails result from light that passes through the
moving blood cells and returns to be detected. This creates a signal that is below the
original motion, but caused by the motion, and therefore is always found posterior to the
original signal.
Figure 7-6 A and B are
en face
images showing the superficial and deeper
retinal layers (SRL and DRL) for a normal subject. The larger vessels that appear similar in
the two images are actually decorrelation tails in the DRL
en face
image. Figure 7-6 E
shows the OCT structural B-scan overlaid with the boundaries of the DRL. This
demonstrates that the DRL
en face
summation clearly does not include the larger vessels.
They appear anyway in Figure 7-6 B due to the decorrelation tails. Figure 7-6 C shows an
en face
image created just above the RPE. The limits of the
en face
summation are shown
C
A
B