NMR chemical shift imaging method

Claim 1

A method for performing chemical shift imaging for a specified nuclear species included in an object which is placed in a uniform static magnetic field, comprising: a step (a) of exciting nuclear spins included in a predetermined area of said object; a step (b) of inverting the sense of said nuclear spins to obtain a spin echo of said nuclear spins; a step (c) of generating a periodically inverting first field gradient along a first direction within said static magnetic field, thereby converting said spin echo into an echo train; a step (d) of measuring the wave shape of said echo train by means of phase sensitive detection and sampling the measured echo train signal while only said first field gradient is generated to provide discrete data; a step (e) of generating in addition to said static magnetic field a second field gradient along a second direction different from said first direction during a predetermined duration preceding the beginning of said measurement step (d), thereby encoding spatial information relating to said second direction into the phase of said nuclear spins; a step (f) of dividing said discrete data into data of odd-numbered echoes in said echo train and data of even-numbered echoes in said echo train, and rearranging said discrete data of the odd-numbered echo data and/or the even-numbered echo data in accordance with the echo number order and the sampling number order to provide a two-dimensional data array; a step (g) of repeating said steps (a) to (f) a plurality of times while changing the amplitude and/or duration of said second field gradient, thereby obtaining at least one three-dimensional data array; and a step (h) of multi-dimensional Fourier-transforming said three-dimensional data with the echo number, sampling number, and sequence repetition number taken as three distinct variables, thereby obtaining spectroscopically resolved multi-dimensional distribution of the nuclear species or local spectra resolved by multi-dimensional location.

Claim 2

A method for performing chemical shift imaging for a specified nuclear species included in an object which is placed in a uniform static magnetic field, comprising: a step (a) of exciting nuclear spins included in a predetermined area of said object; a step (b) of inverting the sense of said nuclear spins to obtain a spin echo of said nuclear spins; a step (c) of generating a periodically inverting first field gradient along a first direction within said static magnetic field, thereby converting said spin echo into an echo train; a step (d) of measuring the wave shape of said echo train by means of phase sensitive detection and sampling the measured echo train signal while only said first field gradient is generated to provide discrete data; a step (e) of generating in addition to said static magnetic field a second field gradient along a second direction different from said first direction during a predetermined duration preceding the beginning of said measurement step (d), thereby encoding spatial information relating to said second direction into the phase of said nuclear spins; a step (f) of dividing said discrete data into data of odd-numbered echoes in said echo train and data of even-numbered echoes in said echo train, and rearranging said discrete data of the odd-numbered echo data and/or the even-numbered echo data in accordance with the echo number order and the sampling number order to provide a two-dimensional data array; a step (g) of repeating said steps (a) to (f) a plurality of times while changing the amplitude and/or duration of said second field gradient, thereby obtaining at least one three-dimensional data array; and a step (h) of multi-dimensional Fourier-transforming said three-dimensional data with the echo number, sampling number, and sequence repetition number taken as three distinct variables, thereby obtaining spectroscopically resolved multi-dimensional distribution of the nuclear species or local spectra resolved by multi-dimensional location.

Claim 7

A method for performing chemical shift imaging for a specified nuclear species included in an object which is placed in a uniform static magnetic field, comprising: a step (a) of selectively exciting nuclear spins included in a specified slice of said object; a step (b) of inverting the sense of said nuclear spins to obtain a spin echo of said nuclear spins; a step (c) of generating a periodically inverting first field gradient along a first direction in a plane of said slice within said static magnetic field, thereby converting said spin echo into an echo train; a step (d) of measuring the wave shape of said echo train by means of phase sensitive detection and sampling the measured echo train signal while only said first field gradient is generated to provide discrete data; a step (e) of generating in addition to said static magnetic field a second field gradient along a second direction which is in said plane and is perpendicular to said first direction during a predetermined duration preceding the beginning of said measurement step (d), thereby encoding spatial information relating to said second direction into the phase of said nuclear spins; a step (f) of dividing said discrete data into data of odd-numbered echoes in said echo train and data of even-numbered echoes in said echo train and rearranging said discrete data of said odd-numbered echo data and/or the even-numbered echo data in accordance with the echo number order and the sampling number order to provide a two-dimensional data array; a step (g) of repeating said steps (a) to (f) a plurality of times while changing the amplitude and/or duration of said second field gradient, thereby obtaining at least one three-dimensional data array; and a step (h) of multi-dimensional Fourier-transforming said three-dimensional data with the echo number, sampling number, and sequence repetition number taken as three distinct variables, thereby obtaining spectroscopically resolved two-dimensional distribution of the nuclear species or local spectra resolved by two-dimensional location.

Claim 8

A method for performing chemical shift imaging for a specified nuclear species included in an object which is placed in a uniform static magnetic field, comprising: a step (a) of selectively exciting nuclear spins included in a specified slice of said object; a step (b) of inverting the sense of said nuclear spins to obtain a spin echo of said nuclear spins; a step (c) of generating a periodically inverting first field gradient along a first direction in a plane of said slice within said static magnetic field, thereby converting said spin echo into an echo train; a step (d) of measuring the wave shape of said echo train by means of phase sensitive detection and sampling the measured echo train signal while only said first field gradient is generated to provide discrete data; a step (e) of generating in addition to said static magnetic field a second field gradient along a second direction which is in said plane and is perpendicular to said first direction during a predetermined duration preceding the beginning of said measurement step (d), thereby encoding spatial information relating to said second direction into the phase of said nuclear spins; a step (f) of dividing said discrete data into data of odd-numbered echoes in said echo train and data of even-numbered echoes in said echo train and rearranging said discrete data of said odd-numbered echo data and/or the even-numbered echo data in accordance with the echo number order and the sampling number order to provide a two-dimensional data array; a step (g) of repeating said steps (a) to (f) a plurality of times while changing the amplitude and/or duration of said second field gradient, thereby obtaining at least one three-dimensional data array; and a step (h) of multi-dimensional Fourier-transforming said three-dimensional data with the echo number, sampling number, and sequence repetition number taken as three distinct variables, thereby obtaining spectroscopically resolved two-dimensional distribution of the nuclear species or local spectra resolved by two-dimensional location.