Strain magnitude estimation based on adaptive incompressibility processing

Two-dimensional phase-sensitive speckle tracking of high frame rate, real-time images has been tested as a possible means for strain rate imaging (SRI) of the beating heart. Due to the poor signal to noise ratio (SNR) of lateral displacement estimates, an adaptive incompressibility method has been developed to produce both shear strain and strain magnitude images with spatial resolution and SNR approaching axial strain images. To test the proposed approach, strain images were produced for a thick-walled, cylindrical phantom modeling cardiac deformations. Strain magnitude images with spatial resolution between 1-2 mm were generated using an array system operating at 5 MHz. These images clearly show low deformation regions in the phantom difficult to identify on tissue velocity derived strain images