FIGURE 3.

Arterial velocimetry at baseline and hyperemia. (A) Blood flow velocity in the superficial femoral artery, during baseline and post-cuff occlusion (reactive hyperemia). Systolic, retrograde, and baseline velocities are indicated (V_s, V_r, and V_b, respectively). Post-ischemia, hyperemia is evaluated in terms of hyperemic index (HI) as the slope of the initial part of the velocity-time curve, peak average velocity (V_P), and duration of hyperemia, referred to as time of forward flow (T_FF). (B) Axial MR image of the thigh perpendicular to the femoral artery. (C) Pre- vs. post-electronic cigarette (e-cig) vaping differences for two parameters, in non-smokers, after a single episode of non-nicotinized e-cig vaping. The same MRI protocol was executed before and after e-cig use (modified from Caporale et al., 2019; Figures 2, 5, with permission from RSNA publisher).