Electron spin resonance enhanced MRI using an echo planar imaging technique

• US 5,287,854 A
• Filed: 10/24/1991
• Issued: 02/22/1994
• Est. Priority Date: 04/24/1989
• Status: Expired due to Fees

• Current Assignee: Amersham Health R&D AB (General Electric Company)
• Original Assignee: Nycomed Innovation AB (GE Healthcare Technologies, Inc.)
• Inventors: Leunbach, Ib
• Primary Examiner(s): Smith, Ruth S.
• Application Number:
  US07/768,202
• Time in Patent Office: 852 Days
• Field of Search: 128/653.2, 128/653.4, 324/307, 324/309, 324/316
• US Class Current: 600/410
• CPC Class Codes: G01R 33/5615 Echo train techniques involving acquiring plural, differently encoded, echo signals after one RF excitation, e.g. using gradient refocusing in echo planar imaging [EPI], RF refocusing in rapid acquisition with relaxation enhancement [RARE] or using both RF and gradient refocusing in gradient and spin echo imaging [GRASE]
• CPC Class Codes: G01R 33/5616 using gradient refocusing, e.g. EPI
• CPC Class Codes: G01R 33/62 using double resonance G01R33/24 takes precedence

Abstract

There is provided an improved magnetic resonance imaging procedure which essentially combines electron spin resonance enhanced MRI with echo planar imaging MRI.

Claims

1. A method of electron spin resonance enhanced magnetic resonance imaging of a subject performed by an echo planar imaging technique, said method comprising the following steps:

(a) exposing said subject to a first radiation of a frequency selected to excite an electron spin resonance transition in a paramagnetic species in said subject,

(b) exposing said subject to at least one pulse of a second radiation of a frequency selected to excite nuclear spin transitions in selected nuclei in said subject,

(c) imposing on said subject at least one spatial information encoding magnetic field gradient,

(d) imposing on said subject a series of magnetic field read gradient pulses, said gradient pulses or sets of said gradient pulses within said series being of alternating polarities,

(e) during at least part of the time said read gradients are imposed, detecting the magnetic resonance signal from said selected nuclei, and

(f) generating from said detected signals an image of at least part of said subject.

2. A method as claimed in claim 1 wherein said subject is a human or non-human animal.

3. A method as claimed in claim 2 comprising introducing into a subject a physiologically tolerable paramagnetic species having an ESR linewidth of up to 2 gauss.

4. A method as claimed in claim 3 wherein said paramagnetic species has an ESR linewidth of up to 1.5 gauss.

5. A method as claimed in claim 1 wherein prior to steps (a) to (f) a primary magnetic field is imposed on said subject.

6. A method as claimed in claim 5 wherein said imaging is effected using a primary magnetic field strength of less than 1T.

7. A method as claimed in claim 5 wherein said imaging is effected using a primary magnetic field strength of less than 0.1T.

8. A method as claimed in claim 5 wherein imaging is effected using a primary magnetic field strength of from 20 to 200 gauss.

9. A magnetic resonance imager for performing ESREMRI, comprising a first radiation source means for irradiating a sample with a first radiation of a frequency selected to excite an electron spin resonance transition in a paramagnetic species in said sample, a second radiation source means for irradiating said sample with at least one pulse of a second radiation of a frequency selected to excite nuclear spin transitions in selected nuclei in said sample, gradient imposing means for imposing at least one magnetic field gradient across said sample, detection means for detecting magnetic resonance signals from said sample, first control means for controlling said gradient imposing means, and second control means for controlling the operation of said detection means, wherein said first control means imposes across said sample magnetic field read gradients of alternating polarities and said second control means causes said detection means to operate during at least part of the time during which read gradients are imposed.

10. An imager as claimed in claim 9, wherein said first and second control means comprises a computer.

11. An imager as claimed in claim 9 further comprising magnetic field generating means for imposing a primary magnetic field on said sample.