DOUBLE-ECHO 3-POINT-DIXON METHOD FOR FAT-SUPPRESSION MRI

A double-echo two-excitation pulse sequence encoding fat and water sig nals for a phase-sensitive three-point Dixon-type analysis (DE-3PD) wa s developed and implemented on a 1.5 T MR imager. Data processing was performed using a previously developed two-dimensional (2D) region-gro wing algorithm, adapted to use double-echo data, Density-, T-1-, and T -2-weighted fat suppression images were obtained from six volunteers u sing the new fat suppression method. The images were compared with cor responding images obtained using frequency-selective excitation fat su ppression (FAT-SAT) and a single-echo three-point-Dixon method (SE-BPD ). The results demonstrate that the DE-3PD sequence shortens the imagi ng time by one-third compared with the SE-3PD method, without loss in image quality. The data also show that a 2D region-growing algorithm e ffectively unwraps the phase of DE-3PD data sets, and that results of DE-BPD fat signal suppression are consistently better than those obtai ned using a standard FATSAT method. The authors conclude that the doub le-echo sequence provides density-, T-1-, and T-2-weighted images that appear to be promising for routine clinical applications.