Patent ID: 7570052

Claim:
A method of generating a magnetic resonance image of an object in cyclic motion, comprising the steps of: (a) defining a desired acceptance window corresponding to an extent of motion over which image data may be combined; (b) defining a series of position bands, together covering the total range of expected motion, to enable object positions within that range to be assigned to one of said bands, the range of motion corresponding to at least one of said bands being less than or equal to the acceptance window, and dividing said series of position bands into a number of groups, each group containing a number of adjacent position bands; (c) selecting a required image resolution, thus defining the number of ky lines to be acquired; (d) generating a ky line acquisition order for a first position band, said order having the features that: (i) each ky line to be acquired is included in the order; (ii) each successive line to be acquired is spaced apart across the ky space; (e) generating a ky line acquisition order for each of the other position bands, such that the acquisition order for each band within a group is circularly shifted by one place with respect to the order for its adjacent band; (f) measuring the object position, and determining which position band corresponds to said object position; (g) substantially simultaneously with step (f), acquiring data corresponding to the next ky line to be acquired for said corresponding position band, according to the line acquisition order for that position band; (h) determining whether data have been acquired for each ky line across the ky space, in any position band, and if so: (i) identifying the set of position bands containing all ky lines that corresponds to a minimum range of motion; and (ii) using the ky data in that set of position bands to construct and display an image; (i) determining whether the range of motion corresponding to the set of position bands identified in step (h)(i) is greater than the desired acceptance window, and if so, repeating the process from step (f).