1. A method for producing an image with an MRI system, the steps comprising: a) acquiring a first NMR signal at a first echo time and a second NMR signal at a second echo time; b) repeating step a) a plurality of times to sample a corresponding plurality of first and second NMR signals; c) forming a first k-space data set with the acquired plurality of first NMR signals; d) forming a second k-space data set with the acquired plurality of second NMR signals; e) rotating a phase of k-space samples in a first of the k-space data sets to form a phase shifted k-space data set; f) combining the phase shifted k-space data set with a second of the k-space data sets to form a combined k-space data set; g) reconstructing a combined image from the combined k-space data set; h) calculating a phase difference between the acquired plurality of first NMR signals and the plurality of second NMR signals; and i) producing an image having a substantially suppressed signal contribution from an unwanted spin species using the combined image and the calculated phase difference.