Dual echo steady state mr imaging using bipolar diffusion gradients

Abstract

The invention relates to a method of MR imaging of an object (10) placed in an examination volume of a MR device (1). It is an object of the invention to enable distortion-free high-quality diffusion weighted imaging (DWI) with minimization of artefacts caused by motion. The method of the invention comprises the following steps: - subjecting the object (10) to a dual echo steady state imaging sequence, a free induction decay signal (FID) and an echo signal (ECHO) being generated in each interval between two successive RF pulses, wherein a pair of diffusion gradient waveforms (GDIF) of equal phase integral and opposed polarity is applied in the interval between the FID signal and the echo signal; - acquiring the FID signals and the echo signals in a number of repetitions of the imaging sequence with varying phase encoding; and - reconstructing a diffusion weighted MR image from the acquired FID signals and echo signals. Moreover, the invention relates to a MR device for carrying out this method as well as to a computer program to be run on a MR device.

Description

technical field [0001] The present invention relates to the field of magnetic resonance (MR) imaging. It relates to a method of MR imaging of an object. The invention also relates to an MR device and to a computer program to be run on the MR device. Background technique [0002] Image-forming MR methods, which exploit the interaction between magnetic fields and nuclear spins to form two- or three-dimensional images, are widely used today, especially in the field of medical diagnostics, because for imaging of soft tissues, they are relatively Advantageous in many respects, it does not require ionizing radiation and is generally non-invasive. [0003] According to a general MR method, an object, eg the body of a patient to be examined, is arranged in a strong homogeneous magnetic field, the direction of which simultaneously defines the axis (usually the z-axis) of the coordinate system on which the measurements are based. The magnetic field produces different energy levels ...

AI Technical Summary

Problems solved by technology

One of the reasons is that the full potential of the signal gain in the steady state cannot be used, because the gradient moments, especially for diffusion-weighted gradients, are unbalanced, and correspondingly, many signal coherent paths are lost

Another reason is the strong sensitivity to bulk motion introduced by routinely used unipolar diffusion gradients

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