Magnetic resonance image reconstruction method with respiratory MOT detection during sampling of central and peripheral K-space areas
AssigneeKoninklijke Philips N.V.
InventorsNadine Gdaniec, Holger Eggers
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Abstract
A magnetic resonance image of a subject is generated by acquiring k-space samples by sampling an elliptical central area of k-space, k-space having a plurality of points. Each point is representative of a potential sample. An elliptical peripheral area of k-space which peripheral area surrounds the central area is partially sampled. Respiratory motion of the subject is detected and the magnetic resonance image of the subject is reconstructed using the k-space samples acquired before the detection of respiratory motion.
Claims7
A method of generating a magnetic resonance image of a subject, the method comprising:
- during a breathhold, acquiring k-space samples by:
- fully sampling an elliptical central area of k-space, wherein the k-space has a plurality of points, each point being representative of a potential sample;
- partially sampling an elliptical peripheral area in k-space, wherein the peripheral area surrounds the central area;
- said partial sampling of the elliptical peripheral area according to:
- random or pseudo-random sampling at a Poisson-disk distribution and a variable density decreasing outward in k-space, at a pre-set sampling reduction factor;
- selection of sampling positions outside a pre-selected minimum distance from an already sampled point and minimizing the distance between successively sampled points;
- repeating the partial sampling of the elliptical peripheral area, increasing the elliptical peripheral area until:
- (a) a pre-set maximum resolution of the acquired k-space samples is reached or
- (b) respiratory motion of the subject is detected;
- and
- reconstructing the magnetic resonance image of the subject using the k-space samples acquired before the detection of respiratory motion.
A medical apparatus for generating a magnetic resonance image of a subject comprising:
- a respiratory motion detector configured to detect respiratory motion of the subject;
- a controller configured to control an RF scan controller and a gradient controller of a magnetic resonance imaging apparatus to:
- fully sample an elliptical central area of the (ky, kz)-plane in k-space, wherein the k-space has a plurality of points, each point being representative of a potential sample and where each point of the (ky,kz)-plane corresponds to a full sampling of a line in k-space along kx;
- partially sample an elliptical peripheral area of the (ky,kz)-plane in k-space, wherein the peripheral area surrounds the central area, said partial sampling of the elliptical peripheral area according to:
- random or pseudo-random sampling at a Poisson-disk distribution with a variable density decreasing outward in the (ky,kz)-plane in k-space, at a pre-set sampling reduction factor,
- selection of sampling positions outside a pre-selected minimum distance from an already sampled point and minimizing the distance between successively sampled points,
- repeating the partial sampling of the elliptical peripheral area of the (ky,kz)-plane, increasing the elliptical peripheral area until a first to occur of:
- (a) a pre-set maximum resolution of the acquired k-space samples is reached or
- (b) respiratory motion of the subject is detected by the respiratory motion detector;
- a processor configured to reconstruct the k-space samples acquired before the detection of respiratory motion into the magnetic resonance image using an acceleration reconstruction technique.
An apparatus for generating a magnetic resonance image of a subject, the apparatus comprising:
- a controller configured to, during a breathhold:
- fully sample data in an elliptical central area of k-space,
- partially sample data in an elliptical peripheral area of k-space adjacent the elliptical central area using a Poisson-disk distribution, such that (1) the sampled peripheral area of k-space progressively expands, and (2) the peripheral region of k-space is sampled more densely closer to the elliptical central area and progressively less densely further from the central area;
- wherein the controller is further configured to stop sampling k-space in response to respiratory motion by the subject being detected by a respiratory motion detector;
- and
- a reconstruction processor configured to reconstruct the data sampled prior to the detection of respiratory motion into the magnetic resonance image.
Dependencies are inferred from the claim text.