  Four-dimensional ultrasound imaging of complex biological systems such as the
brain is technically challenging because of the spatiotemporal sampling
requirements. We present computational ultrasound imaging (cUSi), a new imaging
method that uses complex ultrasound fields that can be generated with simple
hardware and a physical wave prediction model to alleviate the sampling
constraints. cUSi allows for high-resolution four-dimensional imaging of brain
haemodynamics in awake and anesthetized mice.
