Figure 2

Quantification of reactive hyperemia with dynamic oximetry. a) Cross-sectional phase difference image of the thigh, 10 cm below the inferior boundary of the pressure cuff; b) post-ischemia (cuff-release at t = 0) femoral vein oxygen saturation (SvO₂) curve; c) zoomed series of phase images showing relative phase of venous blood during period indicated by horizontal black bar. Darker blue represent represents lower saturation levels. Parametrization of the curve in panel c yields washout time, time of minimum following cuff release, upslope (slope of the linear portion of the curve following minimum), and overshoot, denoting the maximum of the SvO₂ curve relative to baseline (preceding cuff contraction, not shown).