Techniques, systems and machine readable programs for magnetic resonance

• US 9,207,298 B2
• Filed: 03/15/2013
• Issued: 12/08/2015
• Est. Priority Date: 03/23/2011
• Status: Active Grant

• Current Assignee: Millikelvin Technologies LLC
• Original Assignee: Millikelvin Technologies LLC
• Inventors: Kalechofsky, Neal, Hrovat, Mirko
• Primary Examiner(s): Kish, James
• Application Number:
  US13/844,446
• Publication Number:
  US 20130265048A1
• Time in Patent Office: 998 Days
• Field of Search: 600/410, 600/411, 600/419, 324/307, 324/309, 324/319
• US Class Current: 1/1
• CPC Class Codes: A61B 5/055 involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging
• CPC Class Codes: G01R 33/36 Electrical details, e.g. matching or coupling of the coil to the receiver
• CPC Class Codes: G01R 33/48 NMR imaging systems
• 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

The present disclosure provides various methods and systems for performing magnetic resonance studies. In accordance with many embodiments, image or other information of interest is derived from super radiant pulses.

Claims

1. A method for performing quantitative analysis of the amount of a molecule in a sample or subject comprising:

a) providing a magnetic resonance (“

MR”

) device including (i) a main magnet for providing a background magnetic field along a first direction, (ii) at least one radio-frequency (“

RF”

) coil, and (iii) at least one gradient coil that is configured to be controlled to define at least one region of interest;

b) introducing into the MR device at least one supplemental spin reservoir (“

SSR”

) containing a plurality of molecules;

c) adjusting the circuitry of the RF coil in order to induce electromagnetic feedback between the nuclear magnetization of at least one set of nuclei within the SSR and the RF coil to cause the system to achieve a desired relationship between τ

_R and T2;

d) introducing RF pulses into the SSR so that the magnetization of at least one set of nuclei within the SSR is rotated to greater than ninety degrees;

e) analyzing a super radiant (“

SR”

) pulse that results from step d to determine the peaktime and width of the SR pulse;

f) introducing a sample or subject to be studied into the region of interest;

g) introducing RF pulses into the sample or subject and the SSR so that the magnetization of at least one set of nuclei within the SSR is rotated to the same angle as in step c);

h) analyzing a SR pulse that results from step g to determine the peaktime and width of the new SR pulse; and

i) subtracting the pulse obtained in step e from that in step g to obtain quantitative information as to an amount of target molecule in the sample or subject.

2. The method of claim 1, wherein a first radio frequency coil is used to introduce RF pulses into the sample or subject, and a second radio frequency coil is used to induce electromagnetic feedback between the nuclear magnetization of the set of nuclei of interest and the second radio frequency coil.

3. The method of claim 1, wherein the at least one radio frequency coil is used to introduce RF pulses into the sample or subject in a first selectable state, and further wherein the at least one radio frequency coil is also used to induce electromagnetic feedback between the nuclear magnetization of the set of nuclei of interest and the second radio frequency coil when in a second selectable state.

4. A method for performing a magnetic resonance protocol comprising:

a) providing a magnetic resonance (“

MR”

) device including (i) a main magnet for providing a background magnetic field along a first direction, (ii) at least one radio-frequency (“

RF”

) coil, and (iii) at least one gradient coil that is configured to be controlled to define a region of interest;

c) introducing a sample or subject to be studied into the region of interest;

d) introducing RF pulses into the sample or subject via the at least one RF coil to energize nuclei in the sample or subject;

e) inducing electromagnetic feedback between a first set of nuclei in the sample or subject and the at least one radio frequency coil to cause the vector direction of the nuclear magnetization of the first set of nuclei to rotate to a desired angle with respect to the first direction of the background magnetic field while substantially preventing electromagnetic feedback from being induced between a second set of nuclei in the sample or subject and the at least one radio frequency coil;

f)activating a gradient magnetic field in the region of interest in order to destroy the magnetization associated with the first set of nuclei;

g) deactivating the gradient magnetic field;

h) employing RF pulses to rotate a second set of nuclear magnetization to a desired angle;

i) detecting a signal relating to the pulse of transverse magnetization; and

j) processing the signal to form a data set relating to a presence of the second set of nuclei in the sample or subject.

5. The method of claim 4, further comprising processing information obtained from a plurality of pulses of transverse magnetization to produce at least one of (i) an image, (ii) dynamic flow data, (iii) perfusion data, (iii) spectroscopic identity of chemical species, (iv) physiological data, or (v) metabolic data.

6. The method of claim 4, further comprising:

a) inducing electromagnetic feedback to cause the vector direction of the nuclear magnetization of the second set of nuclei to rotate to a desired angle with respect to the first direction of the background magnetic field; and

b) stopping the electromagnetic feedback to permit the second set of nuclei to permit the pulse of transverse magnetization to propagate.

7. The method of claim 4, wherein electromagnetic feedback is induced at least in part by substantially eliminating a gradient magnetic field in the at least one region of interest.

8. The method of claim 4, wherein electromagnetic feedback is induced at least in part by selectively tuning the at least one radio frequency coil to a predetermined resonant frequency.

9. The method of claim 4, wherein the sample to be studied is an in-vivo sample including fat and water, and further wherein a pulse of transverse magnetization is detected with the at least one radio-frequency coil from protons in water, and further wherein substantially no transverse magnetization is detected with the at least one radio-frequency coil from protons in fat.

10. The method of claim 6, wherein a first radio frequency coil is used to introduce RF pulses into the sample or subject, and a second radio frequency coil is used to induce electromagnetic feedback between the nuclear magnetization of the set of nuclei of interest and the second radio frequency coil.

11. The method of claim 6, wherein the at least one radio frequency coil is used to introduce RF pulses into the sample or subject in a first selectable state, and further wherein the at least one radio frequency coil is also used to induce electromagnetic feedback between the nuclear magnetization of the set of nuclei of interest and the second radio frequency coil when in a second selectable state.

12. A method for performing a magnetic resonance protocol comprising:

a) providing a magnetic resonance (“

MR”

) device including (i) a main magnet for providing a background magnetic field along a first direction, (ii) at least one radio-frequency (RF) coil, and (iii) at least one gradient coil that is configured to be controlled to define at least one region of interest;

b) introducing a sample or subject to be studied into the device;

c) defining a region of interest from which to receive a super radiant (“

SR”

) pulse within the sample or subject by adjusting the magnetic field gradient in the region of interest to be substantially zero;

d) introducing RF pulses via the at least one RF coil into the sample or subject to energize nuclei in the sample or subject;

e) inducing electromagnetic feedback between the nuclear magnetization of a first set of nuclei within the sample or subject and the at least one RF coil to cause the vector direction of the nuclear magnetization of the first set of nuclei to rotate to a desired angle with respect to the first direction of the background magnetic field to generate at least one electromagnetic pulse of transverse magnetization M_xy, wherein the vector direction of the nuclear magnetization of a second set of nuclei outside of the region of interest does not substantially change when the at least one electromagnetic pulse is generated; and

e) detecting the pulse of transverse magnetization arising from the region defined in step c) using an RF coil.

13. The method of claim 12, further comprising processing information obtained from one or more pulses of transverse magnetization to produce at least one of (i) an image, (ii) dynamic flow data, (iii) perfusion data, (iii) spectroscopic identity of chemical species, (iv) physiological data, or (v) metabolic data.

14. The method of claim 12, wherein electromagnetic feedback is induced at least in part by selectively tuning the resonant coil to a predetermined resonant frequency.

15. A method for performing magnetic resonance spectroscopic imaging comprising:

a) providing a magnetic resonance (“

MR”

) device including (i) a main magnet for providing a background magnetic field along a first direction, (ii) at least one radio frequency (“

RF”

) resonant feedback enabled coil, and (iii) at least one gradient coil that is configured to be controlled to define at least one region of interest;

b) introducing a sample or subject to be studied into the region of interest;

c) carrying out MR pulse sequence protocols to produce at least one of (i) an image, (ii) dynamic flow data, (iii) perfusion data, (iii) spectroscopic identity of chemical species, (iv) physiological data, or (v) metabolic data; and

d) adjusting circuitry of the RF coil in order to induce electromagnetic feedback between the nuclear magnetization of at least one set of nuclei within the sample and the at least one resonant feedback enabled coil to cause at least one of (i) the vector direction of the nuclear magnetization of the at least one set of nuclei within the sample to rotate to a new desired angle with respect to the direction of the background magnetic field and (ii) the precessional frequency of at least one set of nuclei within the sample to shift with respect to the precessional frequency of other nuclei in the sample.