Magnetic resonance spectroscopy studies of restricted volumes

Claim 2

A magnetic resonance spectroscopic (MRS) method for accurately locating a region of interest within a subject, said method comprising the steps of: applying a first set of two 90° RF pulses during the application of a first gradient pulse of substantially constant value to saturate with each pulse of said first set of two 90° RF pulses a different unwanted region in a first direction leaving as a first unsaturated region in said first direction a region unaffected by either of said first set of two 90° RF pulses, applying a second set of two 90° RF pulses during the application of a second gradient pulse of substantially constant value to saturate with each pulse of said second set of two 90° RF pulses a different unwanted region in a second direction leaving as a second unsaturated region in said second direction a region unaffected by either of said second set of two 90° RF pulses such that only a selected region of interest at the intersections of said first and said second unsaturated regions contains unsaturated spins, applying a 90° excitation pulse to excite said unsaturated spins in said selected region of interest, and acquiring FID signals from said selected region of interest.

Claim 3

A magnetic resonance spectroscopic (MRS) method for accurately locating a volume of interest (VOI) within a subject, said method comprising the steps of: applying a first set of two 90° RF pulses during the application of a first gradient pulse of substantially constant value to saturate with each pulse of said first set of two 90° RF pulses a different unwanted region in a first direction leaving as a first unsaturated region in said first direction a region unaffected by either pulse of said first set of two 90° RF pulses, applying a second set of two 90° RF pulses during the application of a second gradient pulse of substantially constant value to saturate with each pulse of said second set of two 90° RF pulses a different unwanted region in a second direction leaving as a second unsaturated region in said second direction a region unaffected by either pulse of said second set of two 90° RF pulses, applying a third set of two 90° RF pulses during the application of a third gradient pulse of substantially constant value to saturate with each pulse of said third set of two 90° RF pulses a different unwanted region in a third direction leaving as a third unsaturated region in said third direction a region unaffected by either pulse of said third set of two 90° RF pulses such that only a selected VOI at the intersection of said first, second and third unsaturated regions contains unsaturated spins, applying a 90° excitation pulse to excite said unsaturated spins, and acquiring FID signals from said excited spins in said selected VOI.

Claim 4

A magnetic resonance spectroscopic (MRS) method for accurately locating a volume of interest (VOI) within a subject, said method comprising the steps of: applying a first set of two 90° RF pulses during the application of a first gradient pulse of substantially constant value to saturate with each pulse of said first set of two 90° RF pulses a different unwanted region in a first direction leaving as a first unsaturated region in said first direction a region unaffected by either pulse of said first set of two 90° RF pulses, applying a second set of two 90° RF pulses during the application of a second gradient pulse of substantially constant value to saturate with each pulse of said second set of two 90° RF pulses a different unwanted region in a second direction leaving as a second unsaturated region in said second direction a region unaffected by either pulse of said second set of two 90° RF pulses, applying a third set of two 90° RF pulses during the application of a third gradient pulse of substantially constant value to saturate with each pulse of said third set of two 90° RF pulses a different unwanted region in a third direction leaving as a third unsaturated region in said third direction a region unaffected by either pulse of said third set of two 90° RF pulses such that only a selected VOI at the intersection of said first, second and third unsaturated regions contains unsaturated spins, applying a 90° excitation pulse to excite said unsaturated spins, and acquiring FID signals from said excited spins in said selected VOI.

Claim 5

A magnetic resonance spectroscopic (MRS) system for accurately locating a region of interest (ROI) within a subject, said system comprising: means for applying a first set of two 90° RF pulses during the application of a first gradient pulse of one plurality to saturate a different unwanted region for each of said two 90° RF pulses in a first direction leaving a first unsaturated region in said first direction, means for applying a second set of two 90° RF pulses during the application of a second gradient pulse of one plurality to saturate a different unwanted region for each of said two 90° RF pulses of said second set in a second direction leaving a second unsaturated region in said second direction, such that only a selected ROI at the intersection of said first and said second unsaturated regions contains unsaturated spins, means for applying a 90° excitation pulse to excite said unsaturated spins, and means for acquiring FID signals from said selected ROI.

Claim 6

A magnetic resonance spectroscopic (MRS) system for accurately locating a region of interest (ROI) within a subject, said system comprising: means for applying a first set of two 90° RF pulses during the application of a first gradient pulse of one plurality to saturate a different unwanted region for each of said two 90° RF pulses in a first direction leaving a first unsaturated region in said first direction, means for applying a second set of two 90° RF pulses during the application of a second gradient pulse of one plurality to saturate a different unwanted region for each of said two 90° RF pulses of said second set in a second direction leaving a second unsaturated region in said second direction, such that only a selected ROI at the intersection of said first and said second unsaturated regions contains unsaturated spins, means for applying a 90° excitation pulse to excite said unsaturated spins, and means for acquiring FID signals from said selected ROI.

Claim 7

A magnetic resonance spectroscopic (MRS) system for accurately locating a volume of interest (VOI) within a subject, said system comprising: means for applying a first set of two 90° RF pulses during the application of a first gradient pulse of one plurality to saturate a different unwanted region for each of said two 90° RF pulses of said first set in a first direction, means for applying a second set of two 90° RF pulses during the application of a second gradient pulse of one plurality to saturate a different unwanted region for each of said two 90° RF pulses of said second set of two 90° RF pulses in a second direction leaving a second unsaturated region along said second direction, means for applying a third set of two 90° RF pulses during the application of a third gradient pulse of one plurality to saturate yet a different unwanted region for each of said two 90° RF pulses of said third set along a third direction leaving a third unsaturated region along said third direction such that only a selected VOI at the intersection of said first, second and third unsaturated regions contains unsaturated spins, means for applying a 90° excitation pulse to excite said unsaturated spins, and means for acquiring FID signals from said selected VOI.

Claim 8

A magnetic resonance spectroscopic (MRS) system for accurately locating a volume of interest (VOI) within a subject, said system comprising: means for applying a first set of two 90° RF pulses during the application of a first gradient pulse of one plurality to saturate a different unwanted region for each of said two 90° RF pulses of said first set in a first direction, means for applying a second set of two 90° RF pulses during the application of a second gradient pulse of one plurality to saturate a different unwanted region for each of said two 90° RF pulses of said second set of two 90° RF pulses in a second direction leaving a second unsaturated region along said second direction, means for applying a third set of two 90° RF pulses during the application of a third gradient pulse of one plurality to saturate yet a different unwanted region for each of said two 90° RF pulses of said third set along a third direction leaving a third unsaturated region along said third direction such that only a selected VOI at the intersection of said first, second and third unsaturated regions contains unsaturated spins, means for applying a 90° excitation pulse to excite said unsaturated spins, and means for acquiring FID signals from said selected VOI.

Claim 11

The method of claim 1 including a delay between said last set of RF pulses and said VOI 90 degree excitation RF pulse.

Claim 12

The method of claim 5 and applying a delay between said last set of RF pulses and said last VOI 90 degree excitation RF pulse.

Claim 13

The method of claim 5 and the steps of using a frequency modulated radio frequency pulse as the last 90 degree excitation RF pulse.

Claim 14

The method of claim 5 and the step of applying a delay between the last set of RF pulses and said last 90 degree excitation RF pulse.

Claim 15

The method of claim 6 and the step of applying a delay between said last set of RF pulses and said last 90 degree excitation pulse.

Claim 16

The method of claim 7 wherein said delay is variable.

Claim 18

The system of claim 3 or 4 wherein sets of 90 degree RF pulses are frequency modulated.

Claim 19

The system of claim 3 or 4 wherein said VOI 90 degree excitation RF pulse is a frequency modulated RF pulse.

Claim 20

The system of claim 4 including a delay between said last set of RF pulses and said VOI 90 degree excitation RF pulse.

Claim 21

The system of claim 14 and means for applying a delay between said last set of RF pulses and said last VOI 90 degree excitation RF pulse.

Claim 22

The system of claim 14 including means for a frequency modulating the last 90 degree excitation RF pulse.

Claim 23

The system of claim 14 and means for applying a delay between the last set of RF pulses and said last VOI 90° degree excitation RF pulse.

Claim 24

The system of claim 15 and means for applying a delay between said last set and said last VOI 90 degree excitation pulse.

Claim 25

The system of claim 16 including means for varying the delay.