NMR imaging with incommensurate sampling and gradient andulation rates

Abstract

A new class of imaging schemes is reported which is characterized by gradient modulation incommensurate to the sampling rate. The image is constructed as a weighted average of responses where the weight factors depend on the space variables. Various excitation methods for transverse magnetization are possible, such as stochastic rf excitation and pulsed rf excitation, with or without preparation periods for the generation of special initial conditions. Since field gradient switching times are slow, high-field gradients can be employed. Potential applications are in clinical imaging as well as in materials science. The new class of imaging schemes is illustrated by a computer simulation for sinusoidal field gradient modulation and stochastic rf excitation.