ABSTRACT
Strain encoding (SENC) MRI is a relatively new imaging technique that generates images whose pixel intensities are directly related to the amount of tissue deformation. Inspired by the 1-1 spatial modulation of magnetization (SPAMM) tagging pulse sequence (Axel and Dougherty 1989a,b), SENC was developed by Osman et al. to image regional deformation of the myocardium (Osman et al. 2001). The fundamental difference between standard 1-1 SPAMM tagging and SENC MRI is the direction of the tagging planes. In 1-1 SPAMM, the tagging planes are applied perpendicular to the imaging plane (Figure 6.1a), that is, the tagging (modulation) gradients are applied along the x-and/or y-directions, whereas in SENC, the tagging planes are applied parallel to (and therefore lie inside) the imaging slice (Figure 6.1b), that is, the modulation gradient is applied in the z-direction. Therefore, longitudinal and circumferential strains are measured from SENC short-axis (SAX) and long-axis (LAX) slices, respectively (Figure 6.2).
