Systems and methods for identifying the relative contribution of fat and water signals in a magnetic resonance ("MR") image including an algorithm operable for selecting an image signal model, selecting a scan parameter, forming a bias field estimate, applying a bias correction to a phase image, estimating the signal fraction of fat and water at each of a plurality of voxels, and forming a fat-suppressed image, a water-suppressed image, or a combination of a fat-based image and a water-based image. The ("MRI") fat suppression systems and methods requiring only a single image acquisition including an algorithm operable for selecting a relative phase of approximately .theta.=.pi./2 or another suitable relative phase, employing an expectation maximization algorithm to classify the phase of the complex image, and projecting complex vectors into fat and water components to obtain fat and water images.