Koninklijke Philips Corporation N.v.

Silke Hey

Miha Fuderer

Johan Samuel Van Den Brink

Zhaolin Chen

Liesbeth Geerts-Ossevoort

Giuseppe Valvano

Jos Jacques Koonen

Disclosed herein is a medical system () comprising a memory () storing machine executable instructions (). The medical system further comprises a computational system (). Execution of the machine executable instructions causes the computational system to: receive () initial pulse sequence commands (), wherein the initial pulse sequence commands are configured for controlling a magnetic resonance imaging system () to acquire k-space data () following a non-Cartesian k-space sampling pattern ('), wherein the initial pulse sequence commands are configured for controlling the magnetic resonance imaging system to sample the non-Cartesian k-space sampling pattern by repeatedly sampling a Cartesian k-space sampling pattern () that is rotated for each acquisition, wherein the non-Cartesian k-space sampling pattern has an effective water-fat shift direction (′); receive () a chosen water-fat shift direction (); and construct () modified pulse sequence commands by rotating the non-Cartesian k-space sampling pattern such that the effective water-fat shift direction is aligned with the water-fat shift direction.

Adaptive water-fat shift in non-Cartesian magnetic resonance imaging

The invention relates to a method of MR imaging of an object () positioned in an examination volume of a MR device (). It is an object of the invention to enable efficient spiral MR imaging even in situations of strong Bo inhomogeneity. The method of the invention comprises: subjecting the object () to an imaging sequence comprising at least one RF excitation pulse and sinusoidally modulated magnetic field gradients, acquiring MR signals along two or more spiral k-space trajectories () as determined by the sinusoidal modulation of the magnetic field gradients, wherein the origins of the spiral k-space trajectories are offset from each other, and reconstructing an MR image from the acquired MR signals. Moreover, the invention relates to a MR device () and to a computer program for a MR device ().

MR imaging with spiral acquisition

A method of magnetic resonance (MR) imaging includes a phantom that is inexpensive to produce and enables simple, practical and fast assessment of image sharpness, in particular for checking image quality of MR imaging with spiral acquisition. The method includes subjecting a phantom, which comprises a volume filled with a bulk of granules of solid material surrounded by a liquid, to an imaging sequence, acquiring MR signals from the phantom, reconstructing an MR image from the acquired MR signals, and deriving a measure of the local image sharpness in two or more different image regions from the MR image, wherein each image region is a representation of a part of the phantom volume.

Image quality assessment of magnetic resonance images using a phantom

The invention provides for a magnetic resonance imaging system. Instructions cause a processor () controlling the magnetic resonance imaging system to modify () pulse sequence data by omitting at least some of the phase encodings () that encode for volumes outside of the field of view. The pulse sequence data specifies the acquisition of a stack () of two dimensional slices of a field of view (). The pulse sequence data further specifies phase encoding in a direction () perpendicular to the two dimensional slices. The pulse sequence data specifies a maximum SEMAC factor (). The maximum SEMAC factor specifies a maximum number of phase encoding steps in the perpendicular direction for each of the two dimensional slices. The instructions further cause the processor to determine () a slice SEMAC factor for each of the stack of two dimensional slices. The slice SEMAC factor is determined by counting the phase encoding steps that encode for regions within the field of view. The instructions further cause the processor to modify () the pulse sequence data by dividing the stack of two dimensional slices into multiple packages (). Slices within each of the multiple packages are ordered using an outer linear profile in the perpendicular direction. The stack of two dimensional slices are divided into the multiple packages by grouping slices which have a slice SEMAC factor within a predetermined range. Each of the multiple packages is acquired as a series of pulse sequence repetitions. The instructions further cause the processor to modify () the pulse sequence data by reordering the profile order of a package to remove at least some of the phase encodings outside of the field of view.

Metal artifact correction in magnetic resonance imaging

A magnetic resonance imaging (MRI) system () obtains magnetic resonance (MR) images of a volume. The MRI system includes at least one controller () configured to perform a preparation scan () to acquire preparation echo phase information (, PEPI) for a plurality of dynamics of a scan (); output a plurality of pulse sequences (), each pulse sequence is configured for a corresponding dynamic of the plurality of dynamics of the scan and includes a navigator sequence () and an image sequence (); acquire navigation and image information () for each corresponding pulse sequence of the plurality of pulse sequences; and/or form corrected image information () by correcting echo phase information in accordance with the preparation echo phase information, correcting at least one of gradient delay or frequency offset of the image information in accordance with the navigation information.

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Eindhoven, Netherlands

Silke Hey