Magnetic Resonance Imaging with Asymmetric Radial Sampling and Compressed-Sensing Reconstruction

• US 20150126850A1
• Filed: 11/03/2014
• Published: 05/07/2015
• Est. Priority Date: 11/07/2013
• Status: Active Grant

• Current Assignee: Siemens Healthineers AG (Siemens AG)
• Original Assignee: Siemens AG
• Inventors: Nadar, Mariappan S., Speier, Peter, Schmidt, Michaela, Cetingul, Hasan Ertan
• Granted Patent: US 9,918,639 B2
• Time in Patent Office: Days
• US Class Current: 600/413
• CPC Class Codes: A61B 5/004 adapted for image acquisition of a particular organ or body part A61B5/0082 takes precedence; arrangements for optical scanning A61B5/0062
• CPC Class Codes: A61B 5/0044 for the heart
• CPC Class Codes: A61B 5/05 Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves impedance plethysmography A61B5/0295; measuring movement of the entire body or parts thereof A61B5/11; detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof A61B5/24
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/24 Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/7289 Retrospective gating, i.e. associating measured signals or images with a physiological event after the actual measurement or image acquisition, e.g. by simultaneously recording an additional physiological signal during the measurement or image acquisition
• CPC Class Codes: G01R 33/20 involving magnetic resonance medical aspects A61B5/055; magnetic resonance gyrometers G01C19/60
• CPC Class Codes: G01R 33/48 NMR imaging systems
• CPC Class Codes: G01R 33/4818 MR characterised by data acquisition along a specific k-space trajectory or by the temporal order of k-space coverage, e.g. centric or segmented coverage of k-space
• CPC Class Codes: G01R 33/4824 using a non-Cartesian trajectory
• CPC Class Codes: G01R 33/546 Interface between the MR system and the user, e.g. for controlling the operation of the MR system or for the design of pulse sequences
• CPC Class Codes: G01R 33/56 Image enhancement or correction, e.g. subtraction or averaging techniques , e.g. improvement of signal-to-noise ratio and resolution
• CPC Class Codes: G01R 33/561 by reduction of the scanning time, i.e. fast acquiring systems, e.g. using echo-planar pulse sequences
• CPC Class Codes: G01R 33/563 of moving material, e.g. flow contrast angiography
• CPC Class Codes: G01R 33/56308 Characterization of motion or flow; Dynamic imaging
• CPC Class Codes: G01R 33/56325 Cine imaging

Abstract

A method for acquiring cine images using a magnetic resonance imaging (MRI) system includes selecting an asymmetric radial sampling scheme providing an asymmetric view of k-space corresponding to a desired image resolution. Radial k-space data is acquired using the asymmetric radial sampling scheme, wherein slice-orientation of the radial k-space data is continuously modified while acquiring the radial k-space data. A plurality of cine images are reconstructed from the radial k-space data using a compressed-sensing method.

Claims

1. A method for acquiring cine images using a magnetic resonance imaging (MRI) system, the method comprising:

selecting an asymmetric radial sampling scheme providing an asymmetric view of k-space corresponding to a desired image resolution;

acquiring radial k-space data using the asymmetric radial sampling scheme, wherein slice-orientation of the radial k-space data is continuously modified while acquiring the radial k-space data; and

reconstructing a plurality of cine images from the radial k-space data using a compressed-sensing method.

2. The method of claim 1, wherein the asymmetric radial sampling scheme is an interleaved-angle asymmetric radial sampling scheme.

3. The method of claim 2, wherein the interleaved-angle asymmetric radial sampling scheme comprises:

a full-echo sampling scheme portion to be applied in a center region of k-space; and

a secondary sampling scheme portion to be applied in a remaining area of k-space which excludes the center region of k-space.

4. The method of claim 2, wherein the interleaved-angle asymmetric radial sampling scheme is a weak asymmetry sampling scheme.

5. The method of claim 2, wherein the interleaved-angle asymmetric radial sampling scheme is a strong asymmetry sampling scheme.

6. The method of claim 2, wherein the interleaved-angle asymmetric radial sampling scheme is a half-echo sampling scheme.

7. The method of claim 2, wherein the interleaved-angle asymmetric radial sampling scheme distributes the asymmetric view of k-space over 2π

.

8. The method of claim 1, further comprising:

determining a density compensation value corresponding to the asymmetric view of k-space,

wherein the compressed-sensing method applies the density compensation value during the reconstruction of the plurality of cine images.

9. The method of claim 8, wherein the density compensation value corresponding to the asymmetric view of k-space corresponds to a number of samples to be acquired in the asymmetric view of k-space.

10. The method of claim 1, wherein the compressed-sensing method incorporates an estimated coil sensitivity map generated in parallel with the reconstruction.

11. The method of claim 1, wherein the compressed-sensing method enforces L₂-type data consistency and a L₁-type non-smooth penalty with respect to the radial k-space data.

12. A method for acquiring cine images using a magnetic resonance imaging (MRI) system, the method comprising:

selecting an interleaved-angle asymmetric radial sampling scheme providing an asymmetric view of k-space corresponding to a desired image resolution;

acquiring radial k-space data over a number of interleaves using the interleaved-angle asymmetric radial sampling scheme;

segmenting the radial k-space data into a plurality of overlapping temporal windows based on the number of interleaves; and

reconstructing iteratively a plurality of cine images from the plurality of overlapping temporal windows using a compressed-sensing method.

13. The method of claim 12, wherein the radial k-space data is acquired using a Balanced Steady-State Free Precession (bSSFP) sequence.

14. The method of claim 12, further comprising:

determining a density compensation value corresponding to the asymmetric view of k-space,

wherein the compressed-sensing method applies the density compensation value during the reconstruction of the plurality of cine images.

15. The method of claim 14, wherein the density compensation value corresponding to the asymmetric view of k-space corresponds to a number of samples to be acquired in the asymmetric view of k-space.

16. The method of claim 12, wherein the compressed-sensing method incorporates an estimated coil sensitivity map.

17. The method of claim 16, wherein the method further comprises:

generating the estimated coil sensitivity map in parallel with the reconstruction.

18. The method of claim 12, wherein the compressed-sensing method enforces L₂-type data consistency and a L₁-type non-smooth penalty with respect to the radial k-space data.

19. A system for acquiring cine images using a magnetic resonance imaging (MRI) system, the system comprising:

an operator interface configured to select an asymmetric radial sampling scheme providing an asymmetric view of k-space corresponding to a desired image resolution;

a plurality of radio frequency coils configured to acquire radial k-space data using the asymmetric radial sampling scheme, wherein slice-orientation of the radial k-space data is continuously modified while acquiring the radial k-space data; and

a central control computer unit configured to reconstruct a plurality of cine images from the radial k-space data using a compressed-sensing method.

20. The system of claim 19, further comprising:

an ECG acquisition system configured to acquire a cardiac timing signal,

wherein the central control computer unit is further configured to divide the radial k-space data in a plurality of overlapping temporal windows based on the cardiac timing signal and reconstruction of the plurality of cine images is based on the plurality of overlapping temporal windows.