Noninvasive measurement of transmural gradients in myocardial strain with MR imaging.

A method is presented for performing high-resolution strain measurements by using magnetic resonance (MR) tagging. Multispectral radiofrequency pulses are used to produce tagging grids from which strain estimates are obtained with a resolution of 2 mm. A tag detection algorithm is presented that measures the center of a tag line with a precision that ranges from 0.1 to 0.2 mm over the systolic interval. With this method, a transmural gradient in the strain of a normal dog heart was detected.