. Author manuscript; available in PMC: 2019 Feb 1.

Published in final edited form as: Physiol Meas. 2018 Feb 1;39(1):015006. doi: 10.1088/1361-6579/aa9f46

Table 1.

Definitions of waveform characteristic metrics

Dimensional
V_p(t)	Measured Doppler velocity (peak in space)
V_max	Maximum velocity over period
T_per	Duration of cardiac cycle
Non-Dimensional Velocity
V(t)	Normalized velocity = V_p(t)/V_max
V_min	Minimum velocity over period
V_avg	Time-averaged velocity
V₁_/₂ _max	1/2(V_max−V_min) +V_min
V₃_/₄ _max	3/4(V_max−V_min) +V_min
V_Amax	Velocity at instant of maximum acceleration
V_DN	Minimum velocity of dicrotic notch
V_DP	Maximum velocity after dicrotic notch
V_{Avg BDN}	Time-average velocity before dicrotic notch
V_{Avg ADN}	Time-average velocity after dicrotic notch
V_rec	V_{Avg ADN} - V_{Avg BDN}
Acc_max	Maximum acceleration
PI	V*/V_avg
Non-Dimensional Time
t_{V max}	Time when V_p(t)= V_max
t_V ₁_/₂_max	Time when V_p(t)= V₁_/₂ _max
t_V ₃_/₄_max	Time when V_p(t)= V₃_/₄ _max
t_{V DN}	Time when V_p(t)= V_DN
t_{V DP}	Time when V_p(t)= V_DP