Abstract: An apparatus and method for Magnetic Resonance Imaging (MRI) by spiral trajectory scanning comprises an MR imaging device for acquiring and processing data samples of an object to be imaged, wherein the data samples are acquired by spiral trajectory scanning. An interface is coupled to the MR imaging device for receiving operator-defined spiral scanning parameters, and a computer is coupled to the interface and the MR imaging device. The computer is configured to generate an approximated spiral trajectory in k-space in accordance with operator-defined spiral scanning parameters. The approximated spiral trajectory is used by the MR imaging system to perform spiral trajectory scanning.

Abstract: Image artifacts produced by residual magnetization in elements of the gradient field amplifier system are reduced by driving the residual magnetization to a preselected value at the end of each imaging pulse sequence. Reset gradient pulses are produced by the gradient field amplifier system after each signal is acquired to drive the residual magnetization to a selected value. A number of different reset gradient waveforms may be used, and they may be produced in a number of different ways.