Use of MRI spin tagging for position tracking and deformation calculation in a stretching phantom

Tagged, breath-hold CINE MRI has been used to track discrete myocardial points, providing non-invasive characterization of myocardial motion and deformation with time over the entire cardiac cycle. This study investigates the accuracy and precision of tagging for point tracking and deformation calculation on a stretching gel phantom. The motion of material points on a stretching phantom undergoing cyclical motion were tracked with a maximum offset from the true trajectory of 0.09 pixels, and a maximum root mean square deviation around the mean trajectory of 0.19 pixels. The maximum deviation occurred at the last time point for which the tag position could be located. The deformation was between 1.0 and 1.22 over the stretching phase of the cycle and the estimates from tagging were found to be within 0.03 of the true values.