QUANTITATIVE INTERPRETATION OF MAGNETIZATION-TRANSFER

Magnetization transfer contrast (MTC) experiments using off-resonance irradiation have been performed with an agar gel model by systematical ly varying offset frequency, amplitude of the RF irradiation and gel c oncentration. The experimental results are shown to be quantitatively modelled by a two-pool system consisting of a liquid pool with a Loren tzian line shape and a small semisolid pool with a Gaussian lineshape. The fitted model yields physically realistic fundamental parameters w ith a T2 of the semisolid pool of 13 mus. Further analysis shows that the off-resonance irradiation MTC experiment has significant limitatio ns in its ability to saturate the semisolid pool without directly affe cting the liquid component.