Coronary magnetic resonance angiography using motion matched acquisition

• US 6,198,959 B1
• Filed: 02/08/1999
• Issued: 03/06/2001
• Est. Priority Date: 03/27/1998
• Status: Expired due to Term

• Current Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Original Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Inventors: Wang, Yi
• Primary Examiner(s): Jaworski, Francis J.
• Assistant Examiner(s): MANTIS MERCADER, ELENI M
• Application Number:
  US09/246,623
• Time in Patent Office: 757 Days
• Field of Search: 600/413, 600/419, 600/509, 600/521, 324/307, 324/309
• 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 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: A61B 5/411 Detecting or monitoring allergy or intolerance reactions to an allergenic agent or substance
• 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 33/4822 in three dimensions
• CPC Class Codes: G01R 33/563 of moving material, e.g. flow contrast angiography
• CPC Class Codes: G01R 33/5676 Gating or triggering based on an MR signal, e.g. involving one or more navigator echoes for motion monitoring and correction

Abstract

Coronary arteries are imaged using a cardiac gated, 3DFT fast gradient recalled echo MRA pulse sequence. A scout scan is performed to measure motion during a cardiac or respiratory cycle and a quiescent period of minimal artery motion is identified. Image data is acquired during a succession of cardiac cycles, and the view order is selected to sample the center of k-space during the quiescent period of each cardiac and or respiratory cycle to reduce motion artifacts.

Claims

1. A method for imaging arteries using an MRA pulse sequence in which a series of views are acquired to sample k-space, the steps comprising:

a) performing a scout scan using an NMR pulse sequence to measure movement of the arteries during a cardiac cycle;

b) identifying a quiescent period during the cardiac cycle in which the measured artery movement is minimal; and

c) acquiring the views from which an image is reconstructed using the MRA pulse sequence over a succession of cardiac cycles, and arranging the view order in this acquisition such that the views which sample a central region of k-space are acquired during the quiescent periods of the cardiac cycles and views which sample peripheral regions of k-space are acquired during portions of the cardiac cycles outside the quiescent periods of the cardiac cycles.

2. The method as recited in claim 1 in which the arteries are coronary arteries and step a) is performed by:

i) performing the NMR pulse sequence repeatedly during the cardiac cycle to acquire a plurality of NMR echo signals;

ii) transforming the NMR echo signals to produce a scout image;

iii) detecting a cardiac cavity wall in the scout image; and

iv) measuring the movement of the cardiac cavity wall.

3. The method as recited in claim 1 in which the view order is arranged such that views which sample a peripheral region of k-space are acquired for a time period prior to the quiescent period in each of the succession of cardiac cycles.

4. The method as recited in claim 3 in which the view order is arranged such that views which sample the peripheral region of k-space are also acquired for a time period after the quiescent period in each of the succession of cardiac cycles.

5. The method as recited in claim 3 in which the peripheral views acquired prior to each quiescent period are acquired in descending view order.

6. The method as recited in claim 4 in which the peripheral views acquired after each quiescent period are acquired in ascending view order.

7. A method for imaging patient arteries with an MRI system using an MRA pulse sequence in which a series of views are acquired to sample k-space, the steps comprising:

a) performing a scout scan using an NMR pulse sequence to measure movement of the arteries during an acquisition window;

b) dividing the acquisition window into a plurality of time segments including a quiescent time segment during which there is minimal arterial motion;

c) producing a view order table by mapping each time segment to a corresponding region of k-space to be sampled and wherein the quiescent time segment is mapped to a central region of k-space and another time segment is mapped to a peripheral region of k-space;

d) acquiring image data using the MRA pulse sequence during a series of acquisition windows, wherein each region of k-space is sampled during its corresponding time segment in each acquisition window.

8. The method as recited in claim 7 in which the acquisition window occurs at a selected time during the patient'"'"'s cardiac cycle.

9. The method as recited in claim 7 in which the acquisition window occurs at a selected time during the patient'"'"'s respiratory cycle.

10. The method as recited in claim 7 in which the movement is produced by respiratory motion and the acquisition window occurs during a gating window during each respiratory cycle of the patient.

11. The method as recited in claim 10 which includes:

performing a second scout scan to measure movement of the arteries during a cardiac acquisition window;

dividing the cardiac acquisition window into a plurality of cardiac time segments including a cardiac quiescent time segment during which there is minimal arterial motion; and

wherein the view order table produced in step c) includes mapping the cardiac time segments to corresponding regions of k-space.