Dynamic modification of RF array coil/antenna impedance

• US 9,547,056 B2
• Filed: 09/04/2012
• Issued: 01/17/2017
• Est. Priority Date: 09/07/2011
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Duensing, George Randall
• Primary Examiner(s): BONNETTE, RODNEY ANDREW
• Application Number:
  US14/240,448
• Publication Number:
  US 20140203804A1
• Time in Patent Office: 1,596 Days
• US Class Current: 1/1
• CPC Class Codes: G01R 33/3621 NMR receivers or demodulators, e.g. preamplifiers, means for frequency modulation of the MR signal using a digital down converter, means for analog to digital conversion [ADC] or for filtering or processing of the MR signal such as bandpass filtering, resampling, decimation or interpolation
• CPC Class Codes: G01R 33/3628 Tuning/matching of the transmit/receive coil

Abstract

A magnetic resonance (MR) system (10) minimizes noise for modes of an array of coils (28₁, 28₂, . . . , 28_n). The system (10) includes an array of coils (28₁, 28₂, . . . , 28_n) which share impedance. A plurality of preamplifiers (30₁, 30₂, . . . , 30_n) receive a plurality of signals from the array of coils (28₁, 28₂, . . . , 28_n), and a plurality of matching circuits (32₁, 32₂, . . . , 32_n) impedance match the array of coils (28₁, 28₂, . . . , 28_n) to the plurality of preamplifiers (30₁, 30₂, . . . , 30_n). A plurality of receivers (36₁, 36₂, . . . , 36_n) oversample the plurality of preamplified signals at a plurality of different match values. Thereafter, a plurality of separate images may be reconstructed from the oversampled data, each image corresponding to a particular match value. Finally, the image with the highest SNR may be selected.

Claims

1. A magnetic resonance (MR) system with noise figure minimization for modes of an array of coils, said system comprising:

an array of coils which share impedance;

a plurality of preamplifiers receiving a plurality of signals from the array of coils;

a plurality of matching circuits impedance matching the array of coils to the plurality of preamplifiers; and

,

a plurality of receivers oversampling the plurality of preamplified signals at a plurality of different match values.

2. The MR system according to claim 1, wherein the array of coils includes a plurality of RF receive coils.

3. The MR system according to claim 1, wherein the match values correspond to impedances.

4. The MR system according to claim 1, wherein the plurality of receivers each oversample each MR signal from the corresponding coil n-times to produce n-data lines for each MR signal.

5. The MR system according to claim 4, further including:

a match controller which cyclically selects among n-match values such that each of the n-data lines correspond to one of the n-match values.

6. The MR system according to claim 1, wherein the samples include an image for each combination of receive coil and match value.

7. The MR system according to claim 6, wherein an image with a best SNR is selected for each receive coil from the images corresponding to the receive coil.

8. The MR system according to claim 1, further including:

a reconstruction processor which generates a composite image from a plurality of images generated from the samples.

9. A method for noise figure minimization for modes of an array of coils employed in a magnetic resonance (MR) system, said method comprising:

receiving a plurality of signals from an array of coils which share impedance;

preamplifying the plurality of signals using a plurality of preamplifiers;

impedance matching the array of coils to the plurality of preamplifiers; and

,

oversampling the plurality of preamplified signals at a plurality of different match values.

10. The method according to claim 9, wherein the array of coils includes a plurality of RF receive coils.

11. The method according to claim 9, wherein the array of coils is impedance matched to the plurality of preamplifiers according to the plurality of different match values.

12. The method according to claim 9, wherein the samples include an image for each combination of receive coil and match value.

13. The method according to claim 12, further including:

selecting an image with a best SNR for each coil from the images corresponding to the receive coil.

14. The method according to claim 9, further including:

generating a composite image from a plurality of images generated from the samples.

15. The method according to claim 9, wherein the oversampling includes:

oversampling each preamplified signal n-times for each MR signal to produce n-data lines for each MR signal; and

,

cyclically selecting among n-match values such that each of the n-data lines correspond to one of the n-match values.