Atopic dermatitis (AD) often induces vasodilation, potentially impacting the velocity of blood flow within capillaries and vessels. To quantify the velocity change, we have developed and tested a 1.67 MHz 1310 nm Fourier-domain mode-locked (FDML) OCT system for measuring the decorrelation coefficient in blood vessels. This system provides an inter-frame time of 0.33 milliseconds and an A-scan spacing of 10 microns. A flow phantom, comprising a glass capillary tube of 80 μm inner diameter infused with unhomogenized milk by a syringe pump, was designed to test our OCT system mimicking the blood vessel. We collected 280 sequential B-scans at the same Y position of the phantom for a number of the velocity values. Based on variable interscan time analysis (VISTA) processing, we observed a strong correlation between the calculated decorrelation coefficients and the predetermined flow velocities, spanning a range from 0.16 mm/s to 30 mm/s. These findings enable us to explore our clinical hypotheses with in vivo tests.
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