Data collection method and MRI system

• US 20020149366A1
• Filed: 04/16/2002
• Published: 10/17/2002
• Est. Priority Date: 04/17/2001
• Status: Active Grant

• Current Assignee: GE Medical Systems Global Technology Company LLC (GE Healthcare Technologies, Inc.)
• Original Assignee: GE Yokogawa Medical Systems Limited (GE Aerospace)
• Inventors: Asano, Kenji, Kosugi, Susumu
• Granted Patent: US 6,940,280 B2
• Time in Patent Office: Days
• US Class Current: 324/307
• CPC Class Codes: G01R 33/561 by reduction of the scanning time, i.e. fast acquiring systems, e.g. using echo-planar pulse sequences

Abstract

To reduce artifacts caused by sudden change of a phase encode amount, data Hj, Mj, and Lj having a large phase encode amount are collected, and then, when collecting data C_3j−4, C_3j−3, and C_3j−2 having a small phase encode amount, a buffer pulse sequence having an intermediate phase encode amount (+9) or (+49) is inserted one or more times between both.

Claims

1. A data collection method which divides a k space into (2I+1) regions in total of a zeroth region positioned in the center of the phase encode axis direction, two first regions adjacent to the outside of the zeroth region, and an (i+1)th regions adjacent to the outside of an ith (=1 to I−

1, and I≧

2) regions, and repeats an nth (n is one selected from 1 to I) region data collection and the zeroth region data collection while changing the n successively, thereby updating data filling the k space, wherein a pulse sequence of the phase encode amount included in the first region is inserted one or more times between the nth region data collection and the zeroth region data collection.

2. The data collection method of claim 1, wherein the phase encode amount included in the first region is a phase encode amount in which a difference between the phase encode amount included in the first region and the phase encode amount of the first pulse sequence of the zeroth region data collection is smallest.

7. The data collection method of claim 1 or 3, wherein data for bloodstream imaging is collected.

3. A data collection method which divides a k space into (2I+1) regions in total of a zeroth region positioned in the center of the phase encode axis direction, two first regions adjacent to the outside of the zeroth region, and an (i+1)th regions adjacent to the outside of an ith (=1 to I−

1, and I≧

3) regions, and repeats an nth (n is one selected from 1 to I) region data collection and the zeroth region data collection while changing the n successively, thereby updating data filling the k space, wherein;

with n=1 or n=2, a pulse sequence of the pulse encode amount in the first region is inserted (I−

1) times between the nth region data collection and the zeroth region data collection; and

inserting, with n≧

3, a pulse sequence of the phase encode amount included in from an (n−

1)th region to the first region is inserted (I−

1) times in total.

4. The data collection method of claim 3, wherein the phase encode amount included in from the (n−

1)th region to the first region is a phase encode amount in which a difference between the phase encode amount included in from the (n−

1)th region to the first region and the phase encode amount of the first pulse sequence of the zeroth region data collection is smallest.

5. The data collection method of claim 3, wherein when I=3, a k space is divided into seven regions in total of a zeroth region, two first regions, two second regions, and two third regions, the nth region data collection and the zeroth region data collection are repeated while successively selecting the n from 1 to 3, thereby updating data filling the k space, a pulse sequence of the phase encode amount included in the first region is inserted twice between the first region data collection and the zeroth region data collection, a pulse sequence of the phase encode amount included in the first region is inserted twice between the second region data collection and the zeroth region data collection, and a pulse sequence of the phase encode amount included in the second region and a pulse sequence of the phase encode amount included in the first region are inserted between the third region data collection and the zeroth region data collection.

6. The data collection method of claim 3, wherein the phase encode amount included in the first region is a phase encode amount in which a difference between the phase encode amount included in the first region and the phase encode amount of the first pulse sequence of the zeroth region data collection is smallest, and the phase encode amount included in the second region is a phase encode amount in which a difference between the phase encode amount included in the second region and the phase encode amount of the first pulse sequence of the zeroth region data collection is smallest.

8. A data collection method in which:

data having a large phase encode amount is collected; and

then data having a small phase encode amount is collected, wherein when both the phase encode amounts are different greatly, a pulse sequence of an intermediate phase encode amount is inserted one or more times between both.

9. An MRI system comprising:

a transmitting coil for transmitting an RF pulse;

a gradient coil for applying a gradient magnetic field;

a receiving coil for receiving an NMR signal;

a data collection device for driving the transmitting coil, gradient coil, and receiving coil, dividing a k space into (2I+1) regions in total of a zeroth region positioned in the center of the phase encode axis direction, two first regions adjacent to the outside of the zeroth region, and an (i+1)th regions adjacent to the outside of an ith (=1 to I−

1, and I≧

2) regions, and repeating an nth (n is one selected from 1 to I) region data collection and the zeroth region data collection while changing the n successively, thereby updating data filling the k space; and

a buffer pulse sequence inserting device for driving the transmitting coil, gradient coil, and receiving coil and inserting a pulse sequence of the phase encode amount included in the first region one or more times between the nth region data collection and the zeroth region data collection.

15. The MRI system of claim 9 or 11, wherein data for bloodstream imaging is collected.

10. The MRI system of claim 9, wherein the phase encode amount included in the first region is a phase encode amount in which a difference between the phase encode amount included in the first region and the phase encode amount of the first pulse sequence of the zeroth region data collection is smallest.

10-1. An MRI system comprising:

a transmitting coil for transmitting an RF pulse;

a gradient coil for applying a gradient magnetic field;

a receiving coil for receiving an NMR signal;

a data collection device for driving the transmitting coil, gradient coil, and receiving coil, dividing a k space into (2I+1) regions of a zeroth region positioned in the center of the phase encode axis direction, two first regions adjacent to the outside of the zeroth region, and an (i+1)th regions adjacent to the outside of an ith (=1 to I−

1, and I≧

3) regions, and repeating an nth (n is one selected from 1 to I) region data collection and the zeroth region data collection while changing the n successively, thereby updating data filling the k space; and

a buffer pulse sequence inserting device for driving the transmitting coil, gradient coil, and receiving coil, inserting, with n=1 or n=2, a pulse sequence of the phase encode amount in the first region (I−

1) times between the nth region data collection and the zeroth region data collection, and inserting, with n≧

3, a pulse sequence of the phase encode amount included in from an (n−

1)th region to the first region (I−

1) times in total.

12. The MRI system of claim 11, wherein the phase encode amount included in from the (n−

1)th region to the first region is a phase encode amount in which a difference between the phase encode amount included in from the (n−

1)th region to the first region and the phase encode amount of the first pulse sequence of the zeroth region data collection is smallest.

13. The MRI system of claim 11, wherein when I=3, a k space is divided into seven regions of a zeroth region, two first regions, two second regions, and two third regions, the nth region data collection and the zeroth region data collection are repeated while successively selecting the n from 1 to 3, thereby updating data filling the k space, a pulse sequence of the phase encode amount included in the first region is inserted twice between the first region data collection and the zeroth region data collection, a pulse sequence of the phase encode amount included in the first region is inserted twice between the second region data collection and the zeroth region data collection, and a pulse sequence of the phase encode amount included in the second region and a pulse sequence of the phase encode amount included in the first region are inserted between the third region data collection and the zeroth region data collection.

14. The MRI system of claim 11, wherein the phase encode amount included in the first region is a phase encode amount in which a difference between the phase encode amount included in the first region and the phase encode amount of the first pulse sequence of the zeroth region data collection is smallest, and the phase encode amount included in the second region is a phase encode amount in which a difference between the phase encode amount included in the second region and the phase encode amount of the first pulse sequence of the zeroth region data collection is smallest.

16. An MRI system comprising:

a transmitting coil for transmitting an RF pulse;

a gradient coil for applying a gradient magnetic field;

a receiving coil for receiving an NMR signal;

a data collection device for driving the transmitting coil, gradient coil, and receiving coil, collecting data having a large phase encode amount, and collecting data having a small phase encode amount; and

a buffer pulse sequence inserting device for, when both the phase encode amounts are different greatly, inserting a pulse sequence of an intermediate phase encode amount one or more times between both.