Figure 12

DENSE. (a) DENSE pulse sequence is derived from STEAM sequence. Displacement encoding (modulation) and decoding (demodulation) gradients are added after the first and third RF pulses, respectively. Both gradients have equal magnitudes, and they are applied in the direction where displacement information to be obtained. During the mixing period in-between modulation and demodulation, large crusher gradients are applied to dephase any transverse magnetization, such that the remaining magnetization is stored in the longitudinal direction, where it experiences only longitudinal relaxation. The time between the first and second RF pulses is equal to the time between the third RF pulse and data acquisition (= echo time (TE)/2). TM = mixing time; RF = radiofrequency; RO = readout; PE = phase encoding; SS = slice selection. (b) Example of DENSE image of the left ventricle, where representative vectors are drawn at each pixel, with the vector magnitude and direction represent the displacement value and orientation, respectively.