QUANTITATIVE T-2 IMAGING OF PLANT-TISSUES BY MEANS OF MULTI-ECHO MRI MICROSCOPY

A method for quantitative T-2 imaging is presented which covers the la rge range of T-2 values in plants (5 to 2000 ms) simultaneously. The t ransverse relaxation is characterized by phase-sensitive measurement o f many echo images in a multi-echo magnetic resonance imaging sequence , Up to 1000 signal-containing echo images can be measured with an int er-echo time of 2.5 ms at 0.47 T. Separate images of water density and of T-2 are obtained. Results on test samples, on the cherry tomato an d on the stem of giant hogweed are presented, The effects of field str ength, spatial resolution and echo time on the observed T-2 values is discussed, The combination of a relatively low magnetic field strength , short echo time and medium pixel resolution results in excellent T-2 contrast and in images hardly affected by susceptibility artifacts, T he characterization of transverse relaxation by multi-echo image acqui sition opens a new route for studies of water balance in plants. (C) 1 998 Elsevier Science Inc.