Adaptive acquisition and reconstruction of dynamic MR images

• US 20060224062A1
• Filed: 09/01/2005
• Published: 10/05/2006
• Est. Priority Date: 04/14/2005
• Status: Active Grant

• Current Assignee: Nitin Aggarwal, Saptarshi Bandyopadhyay, Yoram Bresler
• Original Assignee: Nitin Aggarwal, Saptarshi Bandyopadhyay, Yoram Bresler
• Inventors: Bandyopadhyay, Saptarshi, Bresler, Yoram, Aggarwal, Nitin
• Granted Patent: US 7,945,305 B2
• Time in Patent Office: Days
• US Class Current: 600/413
• CPC Class Codes: A61B 5/0037 Performing a preliminary scan, e.g. a prescan for identifying a region of interest
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts
• CPC Class Codes: A61B 5/7285 for synchronising or triggering a physiological measurement or image acquisition with a physiological event or waveform, e.g. an ECG signal A61B6/5205, A61B6/541, A61B8/5207, A61B8/543 take precedence
• CPC Class Codes: G01R 33/5673 Gating or triggering based on a physiological signal other than an MR signal, e.g. ECG gating or motion monitoring using optical systems for monitoring the motion of a fiducial marker

Abstract

A method for acquiring MR data from a beating heart during subject respiration includes a prescan phase in which a respiratory compensation table and a k-space sampling schedule are produced. The k-space sampling table is produced using a spatio-temporal model of the beating heart and time sequential sampling theory. During the subsequent scan an imaging pulse sequence which is prospectively compensated for respiratory motion is used to acquire k-space data from the subject. The imaging pulse sequence is repeated to play out the phase encodings in the order listed in the k-space sampling schedule.

Claims

1. A method for acquiring and producing images of a time-varying subject with a magnetic resonance imaging (MRI) system, the steps comprising:

a) performing a prescan of the time-varying subject that includes;

a)i) estimating a dynamic model for the time-varying subject;

a)ii computing a dynamic sampling schedule using the estimated dynamic model, the sampling schedule including information indicative of the position in k-space, order and timing at which k-space image data is to be acquired; and

a)iii selecting a pulse sequence for directing the MRI system to acquire k-space image data from the time-varying subject;

b) performing a scan of the time-varying subject to acquire k-space image data with the MRI system that includes;

b)i acquiring information indicative of the motion of the subject caused by respiration;

b)ii altering during the scan one of the dynamic sampling schedule or the selected pulse sequence to compensate for respiratory motion of the subject; and

b)iii acquiring k-space image data with the MRI system using the sampling schedule and the selected pulse sequence; and

c) reconstructing an image using k-space image data acquired in step b).

2. The method as recited in claim 1 wherein the dynamic model in step a)i includes information about the dual-k-t support of the time-varying subject.

3. The method as recited in claim 1 in which during the pre-scan, step a)i includes acquisition of data with the MRI system.

4. The method as recited in claim 3 which further includes altering the data acquisition during the pre-scan to compensate for respiratory motion of the subject.

5. The method as recited in claim 1 in which the dynamic sampling schedule calculated in step a) enables additional reference data to be acquired with the MRI system during step b).

6. The method as recited in claim 5 in which step b) includes acquiring reference data that includes subject motion information.

7. The method as recited in claim 1 in which step a)i) includes producing a respiratory motion calibration rule that relates motion of the subject to respiratory phase, step b)i) includes estimating the respiratory phase, and step b)ii) employs the respiratory phase and the respiratory motion calibration rule to determine the 5 alteration.

8. The method as recited in claim 7, in which the respiratory motion calibration rule depends on the state of the time-varying subject.

9. The method as recited in claim 1, in which the selected pulse sequence directs the MRI system to sample k-space image data along parallel lines in k-space.

10. The method as recited in claim 1, in which the selected pulse sequence directs the MRI system to sample k-space image data along radial lines in k-space.

11. The method as recited in claim 1 in which the information acquired in step b)i) is indicative of an affine component of the respiratory motion of the subject.

12. The method as recited in claim 1, in which step b)i) further includes acquiring information indicative of subject motion not caused by respiration.

13. The method as recited in claim 1 in which step b)i) is performed at times during the scan determined by information about respiration of the subject.

14. The method as recited in claim 1 in which the dynamic model estimated in step a) is used in the image reconstruction in step c).

15. The method as recited in claim 1 in which the time-varying subject is a beating heart.

16. A method for acquiring and producing an image of a time-varying subject with a magnetic resonance imaging (MRI) system, the steps comprising:

a) performing a prescan of the time-varying subject that includes;

a)i) estimating a dynamic model for the time-varying subject;

a)ii producing a dynamic sampling schedule using the estimated dynamic model, the dynamic sampling schedule including information indicative of the position in k-space, order and timing at which k-space image data is to be acquired;

b) performing a scan of the time-varying subject to acquire k-space image data using the MRI system that includes;

b)i acquiring information indicative of the motion of the subject during the scan caused by respiration;

b)ii acquiring k-space image data with the MRI system in accordance with the dynamic sampling schedule; and

c) reconstructing an image using the k-space image data acquired in step b)ii) and the subject motion information acquired in step b)i).

17. The method as recited in claim 16 wherein the dynamic model in step a)i includes information about the dual-k-t support of the time-varying subject.

18. The method as recited in claim 16 in which step a)i includes acquiring MR data with the MRI system.

19. The method as recited in claim 16 in which the dynamic sampling schedule includes information that enables additional reference data to be acquired with the MRI system during step b).

20. The method as recited in claim 19 in which step b) includes acquiring reference data with the MRI system that includes subject motion information.

21. The method as recited in claim 16 in which step a)i) includes producing a respiratory motion calibration rule that relates motion of the imaged subject to respiratory phase, step b)i) includes estimating the respiratory phase, and step c) employs the respiratory phase and the respiratory motion calibration rule during the image reconstruction.

22. The method as recited in claim 21, in which the respiratory motion calibration rule depends on the state of the time-varying subject.

23. The method as recited in claim 16, in which the k-space image data is acquired with a pulse sequence that samples k-space along a plurality of parallel lines in k-space.

24. The method as recited in claim 16, in which the k-space image data is acquired with a pulse sequence that samples k-space along a plurality of radial lines in k-space.

25. The method as recited in claim 16, in which step b)i) further includes acquiring information indicative of subject motion not caused by respiration.

26. The method as recited in claim 16 in which the dynamic model estimated in step a) is used in the image reconstruction in step c).

27. The method as recited in claim 16 in which the time-varying subject is a beating heart.

28. A method for acquiring and producing an image of a subject with a magnetic resonance imaging (MRI) system, the steps comprising:

a) selecting a pulse sequence and a sampling schedule for directing the MR system to acquire k-space image data from the subject at designated times and k-space locations indicated by the sampling schedule;

b) performing a scan of the subject to acquire k-space image data with the MRI system that includes;

b)i acquiring information indicative of the motion of the subject caused by respiration;

b)ii acquiring k-space data by operating the MRI system with the selected pulse sequence and in accordance with the sampling schedule,

c) producing corrected k-space image data by altering the acquired k-space data to compensate for volumetric changes in the subject caused by respiration, using the motion information acquired in step b)i;

d) reconstructing an image using the corrected k-space image data.

29. The method as recited in claim 28, which further includes:

b)iii altering during the scan one of the sampling schedule or the selected pulse sequence to compensate for respiratory motion of the subject.