Koninklijke Philips Corporation N.V.

Gerrit Hendrik Van Ijperen

Gabriele Marianne Beck

Elwin De Weerdt

Johan Michiel Den Harder

Michel Paul Jurriaan Jurrissen

Ulrike Andrea Blume

Alan Jerry Huang

Hoger Eggers

An object to be MR imaged () is placed in an examination volume of a MR device (). For faster MR imaging a multi-echo imaging technique which is robust with respect to motion is used. The method includes

MR imaging using multi-echo k-space acquisition

The invention relates to a method of MR imaging near metal parts using SEMAC. It is an object of the invention to provide an improved MR imaging technique that is sufficiently fast and robust against susceptibility effects. The invention proposes to apply a weaker slice-selection magnetic field gradient (G) for reduction of ripple-artefacts near metal parts or to apply undersampling in the slice-selection direction of the SEMAC sequence or to apply both these aspects. According to one aspect of the invention, a sparsity constraint is used to make the reconstruction of the undersampled MR images more stable. Moreover, the invention relates to a MR device () and to a computer program to be run on a MR device ().

Metal resistant MR imaging

An object () is placed in an examination volume of a MR device () and imaged using a multi-echo imaging technique which is robust with respect to motion. The imaging includes subjecting the object () to a number of shots of a multi-echo imaging sequence to generate a train of echo signals by each shot and acquiring the echo signals. Each echo signal represents a k-space profile, wherein k-space () is divided into a central k-space part () and one or more peripheral k-space parts (). The central k-space part () is sampled by a single shot of the multi-echo imaging sequence, and the peripheral k-space parts () are sampled by one or more further shots () of the multi-echo sequence; and an MR image is reconstructed from the k-space profiles.

MR imaging using multi-echo segmented k-space acquisition

A device for MRI of a body () placed in an examination volume includes a main magnet () for establishing a substantially homogeneous main magnetic field in the examination volume. Gradient coils () generate switched magnetic field gradients superimposed upon the main magnetic field. An RF antenna () radiates RF pulses towards the body (). A control system () controls the generation of the magnetic field gradients and the RF pulses. A demodulator () receives and samples MR signals. A computer () forms MR images from the signal samples. The computer () is arranged to generate a series of MR signals by subjecting at least a portion of the body () to an MRI sequence, to acquire the MR signals as a plurality of k-space blades according to the PROPELLER scheme, to compute phase errors from the phase differences of pairs of k-space blades having different rotation angles, to perform a phase correction of the acquired k-space blades on the basis of the computed phase errors, and to reconstruct an MR image from the acquired and phase-corrected MR data set.

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Eindhoven, Netherlands

Gerrit Hendrik Van Ijperen