Ultrahigh-resolution MR imaging with gradient refocused three-dimensional spin-warp sequences

Three-dimensional spin-warp imaging (3DFT) is a useful technique for improving the signal-to-noise ratio (S/N), although the extra phase encoding can lead to excessive acquisition time. This problem was solved by use of a gradient refocused 3DFT sequence that permits a repetition time of less than 50 msec. Thus, a 32-section volumetric image can be obtained in less than 4 minutes. Surface coil imaging was performed on spines, using a General Electric Signa system operating at 1.5 T. Pixels of 300 x 300 micros and a section definition of 1.2 mm enabled unequivocal identification of nerve roots while maintaining S/N sufficient to distinguish gray and white matter