TABLE I.

List of Abbreviations.

CEUS	Contrast-enhanced ultrasound
CTRRM	Contrast-to-tissue ratio in RM-mode
CTRB-mode	Contrast-to-tissue ratio in B-mode
CTRI	Contrast-to-tissue ratio improvement of RM-mode over B-mode
$\mathrm{\Delta }{P}_i^{\text{RM},\text{OPT}}$	Optimal difference in backscattered power caused by RM for an MB of size Ri
$\mathrm{\Delta }{P}_i^{\text{RM},\text{SIM}}$	Simulated difference in backscattered power caused by RM for an MB of size Ri
$\mathrm{\Delta }{P}_{\text{pop}}^{\text{RM},\text{SIM}}$	Simulated difference in backscattered power caused by RM for a populations of MB
${\mathrm{\Delta }}_{\text{pop},N}^{\text{RM},\text{SIM}}$	Simulated difference in backscattered power caused by RM for a Gaussian population of MB, normalized to the mean backscattering power during HF1 and HF2
$\mathrm{\Delta }{P}_N^{\text{RM},\text{EXP}}$	Experimental difference in backscattered power caused by RM for a population of MB, normalized to the mean B-mode power of HF1 and HF2
HF	High frequency
IVUS	Intravascular ultrasound
LF	Low frequency
MB	Microbubble
R	Microbubble radius
RM	Radial modulation
VV	Vasa vasorum