NMR chemical shift imaging method with influence of intensity distribution of static magnetic field removed

Claim 1

An NMR chemical shift imaging method comprising: (a) first step of exciting nuclear spins of an object for inspection placed within a static magnetic field; (b) second step of applying a phase encode gradient having a programmable time-intensity product to said static magnetic field along a first direction; (c) third step of applying first and second 180° RF pulses at a time interval and thereby generating first and second Hahn echoes; (d) fourth step of applying a readout gradient having a predetermined intensity to said static magnetic field along a second direction perpendicular to said first direction a plurality of times, generating first and second gradient echoes corresponding to said first and second Hahn echoes, defining time difference between said first Hahn echo and said first gradient echo so as to provide two chemical shifts of spins within said object for inspection with a predetermined phase difference other than 2nπ (where n is an integer), and defining time difference between said second Hahn echo and said second gradient echo so as to provide said two chemical shifts with a phase difference of 2nπ; (e) fifth step of sampling said first and second gradient echoes under the presence of said readout gradient; (f) sixth step of repeating said first to fifth steps a lurality of times while changing the time-intensity produce of said phase encode gradient; (g) seventh step of calculating a first image and a second image respectively from a first data train representing the first gradient echo and a second data train representing the second gradient echo obtained at said sixth step; and (h) eighth step of calculating two spin distribution images corresponding to said two chemical shifts from said first and second images.