One-shot velocimetry using echo planar imaging microscopy

A rapid version of PEPI (pi -echo planar imaging) velocimetry has been impl emented, enabling a velocity image, at microscopic resolution, to be acquir ed in less than 1 s, The velocity map was reconstructed using the phase inf ormation from the ratio of two PEPI images, one obtained with a velocity-en coding filter applied prior to the imaging sequence and the other image wit hout. The acquisition time for each image was about 80 ms and the two compl ete image acquisitions were acquired in one shot in 500 ms. This rapid velo cimetry sequence gave a good representation of laminar pipe flow. It has al so been used to examine extensional flow in a biaxial extension in which th e transient extension takes about 3 s. (C) 2001 Academic Press.