Ultrasound localization microscopy (ULM)

A super-resolution vascular imaging method that breaks the acoustic diffraction limit by injecting gas-filled microbubble contrast agents, imaging them at high frame rate, and localizing the centroid of each isolated bubble echo with sub-wavelength precision; accumulating millions of such localizations over a long acquisition reconstructs a map of the microvasculature down to the scale of individual small vessels and their flow velocities.

For neurotechnology, ULM promises to resolve the fine vascular architecture that underlies the coarser fUS signal, and functional-ULM aims to track activity-linked flow in single vessels. The costs are a required contrast injection, long accumulation times that trade against temporal resolution, and sensitivity to motion — so it is today more an anatomical and physiological mapping tool than a real-time BCI readout.