Dynamic range of harmonic phase magnetic resonance imaging (HARP-MRI)

Harmonic phase (HARP) magnetic resonance imaging (MRI) is an image analysis method for measuring tissue motion and strain from tagged MR images. Previous studies in cardiac tagged MRI have demonstrated its utility in the characterization of myocardial infarction, ischemia, and the reperfusion of stunned myocardium. Recently HARP has also been used in characterizing the motion of the tongue during speech. In this paper, we characterize dynamic range - limits of elongation, compression and rotation - of HARPMRI. Viewing HARP-MRI as a phase demodulation technique, a key simplifying relationship permits us to derive approximate analytic expressions for these quantities. Simulations demonstrate the validity of our analysis and also help to provide intuition for these results.