  Identifying and visualizing vasculature within organs and tumors has major
implications in managing cardiovascular diseases and cancer. Contrast-enhanced
ultrasound scans detect slow-flowing blood, facilitating non-invasive perfusion
measurements. However, their limited spatial resolution prevents the depiction
of microvascular structures. Recently, super-localization ultrasonography
techniques have surpassed this limit. However, they require long acquisition
times of several minutes, preventing the detection of hemodynamic changes. We
present a fast super-resolution method that exploits sparsity in the underlying
vasculature and statistical independence within the measured signals. Similar
to super-localization techniques, this approach improves the spatial resolution
by up to an order of magnitude compared to standard scans. Unlike
super-localization methods, it requires acquisition times of only tens of
milliseconds. We demonstrate a temporal resolution of 25Hz, which may enable
functional super-resolution imaging deep within the tissue, surpassing the
temporal resolution limitations of current super-resolution methods, e.g. in
neural imaging. The sub-second acquisitions make our approach robust to motion
artifacts, simplifying in-vivo use of super-resolution ultrasound.
