Microscopic displacement imaging with pulsed field gradient turbo spin-echo NMR

We present a pulse sequence that enables the accurate and spatially resolve d measurements of the displacements of spins in a variety of (biological) s ystems. The pulse sequence combines pulsed field gradient (PFG) NMR with tu rbo spin-echo (TSE) imaging. It is shown here that by ensuring that the pha se of the echoes within a normal spin-echo train is constant, displacement propagators can be generated on a pixel-by-pixel basis. These propagators a ccurately describe the distribution of displacements, while imaging time is decreased by using separate phase encoding for every echo in a TSE train. Measurements at 0.47 T on two phantoms and the stem of an intact tomato pla nt demonstrate the capability of the sequence to measure complete and accur ate propagators, encoded with 16 PFG steps, for each pixel in a 128 x 128 i mage (resolution 117 x 117 x 3000 mu m) within 17 min. Dynamic displacement studies on a physiologically relevant time resolution for plants are now w ithin reach. (C) 2000 Academic Press.