Abstract: A method for rephasing one or more of the motion components of moving material in a nuclear magnetic resonance imaging system, including velocity, acceleration, pulsatility and higher order motion components. Gradient pulses are applied in one or more of the read, phase encode and slice select directions, and subsequent gradients are then applied in one or more of such directions so that the total net phase in such direction is zero for the desired motion component and non-zero for static material.

Abstract: A pulse sequencer (40) controls a resonance excitation controls circuit (22), an inversion pulse controls circuit (24), a slice select gradient controls circuit (32), a read gradient controls circuit (34), and a phase encode gradient controls circuit (36) to cause an appropriate gradient pulse imaging sequence to be generated in the image region. The operator selects an appropriate imaging sequence such as a spin echo, inversion recovery, multi-echo, radient echo, or other conventional imaging sequence and the parameters, such as the number of repetitions, from an image pulse sequence and motion desensitization memory (44, 46). In the exemplary pulse sequences of FIGS. 2-4, this memory directs the formation of RF pulses (62, 66), slice selection pulses (60, 64) and read gradient pulse (70), phase encode gradient pulse (72), and the appropriate additional gradient pulses for rephasing signals from one or more of static, constant velocity, accelerating, and pulsatilitory tissue in the image region.

Abstract: A main magnetic field coil (10) and control (12) cause a generally uniform main magnetic field through an image region. A resonance excitation control (22) causes an R.F. coil (20) to generate excitation pulses (100). A slice gradient control (32) and a read gradient control (34) cause a gradient coil (30) to generate complementary slice selection gradient profiles (112, 114) and complementary read gradient profiles (122, 124) in such a manner that the effective first moment in time is substantially zero. By time shifting a pulse in one or both of the slice selection and read gradient sequences (FIGS. 3 and 4), resonating nuclei in the selected slice can be phase encoded. A transform algorithm (40) transforms field echo signals (102) received by the R.F. coil into image representations.

Abstract: A main magnetic field coil and control cause a generally uniform main magnetic field through an image region. A resonance excitation control causes an R.F. coil to generate excitation pulses. An inversion pulse control causes the R.F. coil to generate a first 180 degree inversion pulse after the excitation pulse and a second 180 degree inversion pulse immediately preceding the excitation pulse. A slice gradient control and a read gradient control cause a gradient coil to generate complimentary slice selection gradients and complimentary read gradient profiles on either side of the first inversion pulse in such a manner that the effective first moment in time is substantially zero. By time shifting one or both of the slice selection and read gradients, resonating nuclei in the selected slice can be phase encoded. A transform algorithm transforms resonance signals received by the R.F. coil into image representations.