Fig. 1.

Combined slice-following scheme with CSPAMM results in the orthogonal projection of material points on the central cross sectional plane of the imaged slab. For example, at time t_0, the position of a selected material point on the tagged slice is denoted by r(t₀), and the projection of this point after the CSPAMM operation on the central cross-sectional short-axis plane is denoted by x^SA(t₀). At a later time t_n, the position of the same material point on the now deformed tagged slice is denoted by r(t_n). The deformed tagged slice continues to remain within the larger imaged slab, and the projection of the material point r(t_n) after the CSPAMM operation on the central cross-sectional plane is denoted by x^SA(t_n). Using HARP 2D tracking we can now track the true two dimensional displacement vector from x^SA(t₀) to x^SA(t_n).