Mr imaging using navigators

Abstract

The invention relates to a method of magnetic resonance (MR) imaging of at least a portion of a body () placed in a stationary and substantially homogeneous main magnetic field. The method comprises the following steps; —exciting nuclear magnetization selectively within a spatially restricted volume of interest () by subjecting the portion to an imaging sequence (IMG) comprising at least one RF pulse (α) and switched magnetic field gradients (GX/GY); —acquiring at least one MR imaging signal from the volume of interest (); —exciting nuclear magnetization within a spatially restricted navigator volume () by subjecting said portion to a navigator sequence (NAV) comprising at least one RF pulse and switched magnetic field gradients, wherein the navigator volume () at least partially overlaps with the volume of interest (); —acquiring at least one MR navigator signal from said navigator volume (); —reconstructing a MR image from the acquired MR imaging signals. It is an object of the invention to enable MR imaging with reliable motion detection and high image quality. For this purpose, the invention proposes that the nuclear magnetization within the volume of interest () is transformed back into longitudinal magnetization prior to application of the navigator sequence (NAV) by subjecting said portion to an unlabeling sequence (UNLBL) comprising at least one RF pulse (−α).