Figure 3.

Principles of microbubble super-localization. (a) The scattered ultrasound wave is several orders of magnitude larger that the microbubble diameter. (b) Super-localization strategies provide microbubble localization information that is much smaller than the ultrasound wavelength. The localization accuracy is inherently limited by the Cramér-Rao lower bound of the ultrasound imaging system and beamforming process which include factors such as ultrasound frequency, bandwidth, signal-to-noise-ratio (SNR), and correlation between the true microbubble signal and the estimated template [78].