LOW-FIELD MAGNETIC RESONANCE SYSTEM (LF-MRS) FOR PRODUCING AN MRI IMAGE

• US 20140103927A1
• Filed: 01/31/2012
• Published: 04/17/2014
• Est. Priority Date: 02/01/2011
• Status: Abandoned Application

• Current Assignee: Aspect Imaging Ltd.
• Original Assignee: Aspect Imaging Ltd.
• Inventors: Rapoport, Uri
• Application Number:
  US13/982,760
• Publication Number:
  US 20140103927A1
• Time in Patent Office: Days
• US Class Current: 324/309
• CPC Class Codes: G01R 33/34015 Temperature-controlled RF coils
• CPC Class Codes: G01R 33/34023 Superconducting RF coils
• CPC Class Codes: G01R 33/3806 Open magnet assemblies for improved access to the sample, e.g. C-type or U-type magnets
• CPC Class Codes: G01R 33/445 MR involving a non-standard magnetic field B0, e.g. of low magnitude as in the earth's magnetic field or in nanoTesla spectroscopy, comprising a polarizing magnetic field for pre-polarisation, B0 with a temporal variation of its magnitude or direction such as field cycling of B0 or rotation of the direction of B0, or spatially inhomogeneous B0 like in fringe-field MR or in stray-field imaging
• CPC Class Codes: G01R 33/5601 involving use of a contrast agent for contrast manipulation, e.g. a paramagnetic, super-paramagnetic, ferromagnetic or hyperpolarised contrast agent
• CPC Class Codes: G01R 33/5608 Data processing and visualization specially adapted for MR, e.g. for feature analysis and pattern recognition on the basis of measured MR data, segmentation of measured MR data, edge contour detection on the basis of measured MR data, for enhancing measured MR data in terms of signal-to-noise ratio by means of noise filtering or apodization, for enhancing measured MR data in terms of resolution by means for deblurring, windowing, zero filling, or generation of gray-scaled images, colour-coded images or images displaying vectors instead of pixels image data processing or generation, in general G06T

Abstract

Low-field magnetic resonance system (LF-MRS) for producing a high-Q MRI image, said LF-MRS comprising: a. Low-field magnetic resonance device (LF-MRD); said LF-MRD is characterized by Q-value, Q_MRD, such that the Q-value of said LF-MRS, QMRS, is a function F₁ of said Q_MRD, represented by F₁(Q_MRD); b. a cryogenically cooled RF coil in connection with said LF-MRD; said cryogenically cooled RF coil is characterized by Q-value, Q_RF, c. a contrast agent (CA) adapted to be introduced into a specimen prior to the introduction of said specimen into said RF coil; The affect of said F₆ on said Q_MRS is significantly greater than the affect of said of predetermined function G on said Q_MRS, said function G is represented by either one of: G(F₁, F₂, F₃, F₄, F₅); G(F₁); G(F₂); G(F₃): G(F₄); G(F₅).

Claims

1-49. -49. (canceled)

50. A low-field magnetic resonance system (LF-MRS) for producing a high-Q MRI image, said LF-MRS comprising:

a. a low-field magnetic resonance device (LF-MRD);

said LF-MRD is characterized by Q-value, Q_MRD, such that one selected from a group consisting of the Q-value of said LF-MRS, Q_MRS, and the Signal to Noise Ratio (SNR) of said LF-MRS, SNR_MRS, is a function F₁ of said Q_MRD, represented by F₁(Q_MRD);

b. a cryogenically cooled RF coil in connection with said LF-MRD;

said cryogenically cooled RF coil is characterized by Q-value, Q_RF, such that;

i. said one selected from said group consisting of said Q_MRS and said SNR_MRS is a function F₂ of said Q_RF, represented by F₂(Q_RF);

or

ii. said one selected from said group consisting of said Q_MRS and said SNR_MRS is a function F₃ of said Q_RF and Q_MRD, represented by F₃(Q_RF, Q_MRS)

c. a contrast agent (CA) adapted to be introduced into a specimen prior to the introduction of said specimen into said RF coil;

such that;

i. said one selected from said group consisting of said Q_MRS and said SNR_MRS is affected by said contrast agent according to predetermined function F₄, represented by F₄(contrast agent);

ii. said one selected from said group consisting of said Q_MRS and said SNR_MRS is a function F₅ of said Q_RF and said contrast agent, represented by F₅(QRF, contrast agent); and

iii. said one selected from said group consisting of said Q_MRS and said SNR_MRS is a function F₆ of said Q_RF, Q_MRD and said contrast agent, represented by F₆(Q_RF, Q_MRD, contrast agent)

wherein the effect of said F₆ on said one selected from said group consisting of said Q_MRS and said SNR_MRS is significantly greater than the effect of said predetermined function G on said one selected from said group consisting of said Q_MRS and said SNR_MRS, said function G is represented by any one of;

i. G(F₁, F₂, F₃, F₄, F₅);

ii. G(F₁);

iii. G(F₂);

iv. G(F₃);

v. G(F₄); and

,

vi. G(F₅).

51. The LF-MRS of claim 50, wherein said effect of said F₆ is greater than G by at least an order of magnitude when compared with any one of F₁, F₂, F₃, F₄, F₅ and any combination thereof.

52. The LF-MRS of claim 50, wherein said SNR_MRS is increased by at least 2 orders of magnitude when compared with any one of F₁, F₂, F₃, F₄, F₅ and any combination thereof.

53. The LF-MRS according to claim 50, further comprising a frequency locking device located in said LF-MRS for locking an RF frequency generated in said RF coil thereby locking said RF frequency to a resonant frequency of the excited nuclei.

54. The LF-MRS according to claim 50, wherein said cryogenically cooled RF coil is located in an air gap formed between magnetic pole pieces of a main magnet of said LF-MRD.

55. The LF-MRS according to claim 50, wherein said RF coil comprises one of a group consisting of:

at least one copper conductor said at least one copper conductor is cooled to the temperature of liquid nitrogen thereby enhancing the Q-value of said RF coil to a value of 100;

at least one high temperature superconducting coil said at least one high temperature superconducting coil is cooled to a temperature of 100°

K thereby enhancing the Q-value of the RF coil to a value of 1000; and

at least one low temperature superconducting coil said at least one low temperature superconducting coil is cooled to the temperature of liquid helium thereby enhancing the Q-value of said RF coil to a value of 10000.

56. The LF-MRS according to claim 50, wherein said magnetic contrast agent is selected from a group consisting of magnetite, maghemite, monocrystalline iron oxide nanoparticles, superparamagnetic iron oxide (SPIO) and gadolinium based compounds and any combination thereof.

57. The LF-MRS according to claim 50, wherein said cryogenically cooled RF coil is located at a predetermined distance from said LF-MRS;

said predetermined distance is between 20 cm to 25 cm from said LF-MRS.

58. A low-field magnetic resonance system (LF-MRS) for producing an MRI image, said LF-MRS system comprising:

(a) a low-field magnetic resonance device (LF-MRD);

said LF-MRD is characterized with Q-valueLF-MRD; and

, means for generating an MRI signal;

(b) a cryogenically cooled RF coil in connection with said LF-MRD;

said RF coil is characterized with Q-valueRF-Coil; and

,

(c) a contrast agent adapted to be introduced into a specimen prior to the introduction of said specimen into said RF coil;

said contrast agent is adapted to increase the Q-value of said LF-MRS, Q-valueLF-MRS;

wherein said LF-MRD, said cryogenically cooled RF coil and said contrast agent increase the Q-value of said LF-MRS such that said increase is greater than the linear sum of said Q-valueRF-Coil increase, said Q-valueLF-MRD increase and said contrast agent.

59. The LF-MRS according to claim 58, further comprising a frequency locking device located in said LF-MRS for locking an RF frequency generated in said RF coil thereby locking said RF frequency to a resonant frequency of the excited nuclei.

60. The LF-MRS according to claim 58, wherein said cryogenically cooled RF coil is located in an air gap formed between magnetic pole pieces of a main magnet of said LF-MRD.

61. The LF-MRS according to claim 58, wherein said RF coil comprises one of a group consisting of:

at least one copper conductor said at least one copper conductor is cooled to the temperature of liquid nitrogen thereby enhancing the Q-value of said RF coil to a value of 100;

at least one high temperature superconducting coil said at least one high temperature superconducting coil is cooled to a temperature of 100°

K thereby enhancing the Q-value of the RF coil to a value of 1000; and

at least one low temperature superconducting coil said at least one low temperature superconducting coil is cooled to the temperature of liquid helium thereby enhancing the Q-value of said RF coil to a value of 10000.

62. The LF-MRS according to claim 58, wherein said magnetic contrast agent is selected from a group consisting of magnetite, maghemite, monocrystalline iron oxide nanoparticles, superparamagnetic iron oxide (SPIO) and gadolinium based compounds and any combination thereof.

63. The LF-MRS according to claim 58, wherein said cryogenically cooled RF coil is located at a predetermined distance from said LF-MRS;

said predetermined distance is between 20 cm to 25 cm from said LF-MRS.

64. A method for producing an MRI image, said method comprises steps of:

a. providing a low-field magnetic resonance device (LF-MRD);

said LF-MRD is characterized by Q-value, Q_MRD, such that one selected from a group consisting of the Q-value of said LF-MRS, Q_MRS, and the Signal to Noise Ratio (SNR) of said LF-MRS, SNR_MRS, is a function F₁ of said Q_MRD, represented by F₁(Q_MRD);

b. providing a cryogenically cooled RF coil in an air gap formed between magnetic pole pieces of a main magnet of said LF-MRD;

said cryogenically cooled RF coil is characterized by Q-value, Q_RF, such that;

i. said one selected from said group consisting of said Q_MRS and said SNR_MRS is a function F₂ of said Q_RF, represented by F₂(Q_RF); and

,

ii. said one selected from said group consisting of said Q_MRS and said SNR_MRS is a function F₃ of said Q_RF and Q_MRD, represented by F₃(Q_RF, Q_MRS);

c. introducing a contrast agent into a specimen prior to the introduction of said specimen into said RF coil, such that;

i. said one selected from said group consisting of said Q_MRS and said SNR_MRS is affected by said contrast agent according to predetermined function F₄, represented by F₄(contrast agent);

ii. said one selected from said group consisting of said Q_MRS and said SNR_MRS is a function F₅ of said Q_RF and said contrast agent, represented by F₅(Q_RF, contrast agent);

iii. said one selected from said group consisting of said Q_MRS and said SNR_MRS is a function F₆ of said Q_RF, Q_MRD and said contrast agent, represented by F₆(Q_RF, Q_MRS, contrast agent); and

.

d. generating an MRI signal;

wherein the effect of said F₆ on said one selected from said group consisting of said Q_MRS and said SNR_MRS is greater than the effect of said predetermined function G on said one selected from said group consisting of said Q_MRS and said SNR_MRS, said function G is represented by any one of;

i. G(F₁, F₂, F₃, F₄, F₅);

ii. G(F₁);

iii. G(F₂);

iv. G(F₃);

v. G(F₄); and

,

vi. G(F₅).

65. The method for producing an MRI image according to claim 64, wherein said effect of said F₆ is greater by at least an order of magnitude when compared with any one of F₁, F₂, F₃, F₄, F₅ or any combination thereof.

66. The method for producing an MRI image according to claim 64, wherein said effect of said F₆ is greater by at least two orders of magnitude when compared with any one of F₁, F₂, F₃, F₄, F₅ or any combination thereof.

67. The method for producing an MRI image according to claim 64, wherein said method further comprises locating a frequency locking device in said LF-MRS for locking an RF frequency generated in said RF coil thereby locking said RF frequency to a resonant frequency of the excited nuclei.

68. The method for producing an MRI image according to claim 64, further comprising a step of locating said cryogenically cooled coil at a predetermined distance from said MRD;

said predetermined distance is between 20 cm to 25 cm from said MRD.

69. The method for producing an MRI image according to claim 64, further comprising a step of cooling said RF coil to a temperature selected from a group consisting of:

the temperature of liquid nitrogen thereby enhancing the Q-value of said RF coil to a value of 100;

a temperature of 100°

K thereby enhancing the Q-value of said RF coil to a value of 1000; and

the temperature of liquid helium thereby enhancing the Q-value of said RF coil to a value of 10000.

70. The method for producing an MRI image according to claim 64, additionally comprising a step of selecting said magnetic contrast agent from a group consisting of magnetite, maghemite, monocrystalline iron oxide nanoparticles, superparamagnetic iron oxide (SPIO) and gadolinium based compounds and any combination thereof.