High resolution/reduced slice width magnetic resonance imaging and spectroscopy by signal combination and use of minimum phase excitation pulses

摘要

A high resolution NMR signal is obtained for a thin slice through a body by combining signals in which excitation k-space is covered in two or more excitations. An RF excitation pulse is applied along with an oscillating (e.g. triangular, trapezoidal, sinusoidal) wave modulated magnetic gradient with the RF pulse having nulls corresponding to zero values of the gradient. The RF pulse is applied a second time with the magnetic gradient inverted NMR signals detected following the application of the RF excitation pulses are summed. Minimum phase RF pulses can be employed to reduce signal dropout and reduce artifacts.