1. 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; (c) selecting a required image resolution, thus defining the number of ky lines to be acquired; (d) acquiring ky data and object position data according to a first phase of data collection, comprising the steps of: (1) generating an acquisition order for a first set of ky lines (the “first pass acquisition order”), such that each ky line to be acquired is included once in the order; (2) measuring the object position, and determining which position band corresponds to said object position; (3) substantially simultaneously with step (d)(2), acquiring ky data corresponding to the next ky line in the first pass acquisition order; (4) storing the object position and ky data so acquired; (5) repeating the method from step (d)(2) until data have been collected for all ky lines; (e) acquiring ky data and object position data according to a second phase of data collection, comprising the steps of: (1) measuring the object position, and determining which position band corresponds to said object position (the “current position”); (2) determining, from previously collected data, the ky line or lines (the “candidate lines”) for which the ky data collected closest to the current position (the “most proximate data”) is farthest away from the current position, and choosing this, or one of these candidate lines to be the next ky line to be acquired; (3) substantially simultaneously with step (e)(1), acquiring ky data corresponding to the next ky line so chosen; (4) storing the object position and ky data so acquired; (5) if all ky lines have been collected within the desired acceptance window, then creating and displaying an image using the ky lines, otherwise, (6) repeating the method from step (e)(1) onwards until all ky lines have been collected within the desired acceptance window, then creating and displaying an image using the ky lines within the acceptance window.