Apparatus and methods of use are provided for complex flow imaging and analysis that is non-invasive, accurate, and time-resolved. It is particularly useful in imaging of vascular flow with spatiotemporal fluctuations. This apparatus is an ultrasound-based framework called vector projectile imaging (VPI) that can dynamically render complex flow patterns over an imaging view at millisecond time resolution. The VPI apparatus and methods comprise: (i) high-frame-rate broad-view data acquisition (based on steered plane wave firings)； (ii) flow vector estimation derived from multi-angle Doppler analysis (coupled with data regularization and least-squares fitting)； and (iii) dynamic visualization of color-encoded vector projectiles (with flow speckles displayed as adjunct).
