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Supplementary Fig. 1. Procedure for measuring vessel parameters based on an intensity graph
using Medical Image Processing, Analysis, and Visualization (MIPAV).
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1. A circular scan using SD-OCT was performed.
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2. Identify the largest or second largest artery and vein which had sufficient image
quality for measuring, with no artery and/or vessel crossover. The circular scan and
cross-sectional image were captured with a 400% enlarged scale, and selected with a
drawn line VOI using MIPAV.
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3. First, a line VOI line was drawn vertically at the center of the vessel
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4. Then, an intensity graph was made using a left click, and the line was moved
horizontally to find a proper location that provided peaks where the upper wall,
lumen, and lower wall were well resolved (when the line was moved horizontally, the
intensity graph changed in real-time).
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5. Finally, after finding the proper location, the intensity data with distance was
generated using the output window in MIPAV to find the distance corresponding to
the boundary.
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6.
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Definition of vessel parameters:
The upper wall thickness was determined from the distance that corresponded to the
lowest intensity between the first peak of the nerve fiber layer and the second peak of
the blood vessel, to the distance that corresponded to the lowest intensity between the
second peak of the blood vessel and the third peak of blood flow (A). If the peak of
the nerve fiber was minimal, and the lowest point was difficult to find, we then 1)
found an inflection (D), or 2) defined the starting point as corresponding to the same
intensity to the lowest intensity between the first peak and second peak (E). Luminal
diameter was determined from the distance that corresponded to the lowest peak
between the upper wall and upper hyperreflectivity which was generated by blood
flow to the distance that corresponded to the lowest peak between the lower
hyperreflectivity of the blood flow and the peak of the lower wall (B). The lower wall
thickness was determined from the distance of the right most peak (C). The intensity
continuously decreased below the bottom border of the lower wall and the end point
was defined as corresponding to the same intensity as the lowest intensity between
the blood flow peak and the right most peak (F, or G).