Two-dimensional (2-D) strain fields were estimated non-invasively in two simple experimental models of closed-head brain injury. In the first experimental model, shear deformation of a gel was induced by angular acceleration of its spherical container. In the second model the brain of a euthanized rat pup was deformed by indentation of its skull. Tagged magnetic resonance images (MRI) were obtained by gated image acquisition during repeated motion. Harmonic phase (HARP) images corresponding to the spectral peaks of the original tagged MRI were obtained, following procedures proposed by Osman, McVeigh and Prince . Two methods of HARP strain analysis were applied, one based on the displacement of tag line intersections, and the other based on the gradient of harmonic phase. Strain analysis procedures were also validated on simulated images of deformed grids. Results show that it is possible to visualize deformation and to quantify strain efficiently in animal models of closed head injury.
Measurement of Strain in Physical Models of Brain Injury: A Method Based on HARP Analysis of Tagged Magnetic Resonance Images (MRI)
Contributed by the Bioengineering Division for publication in the JOURNAL OF BIOMECHANICAL ENGINEERING. Manuscript received by the Bioengineering Division November 20, 2003; revision received January 26, 2004. Associate Editor: A. D. McCulloch.
Bayly,, P. V., Ji,, S., Song,, S. K., Okamoto,, R. J., Massouros,, P., and Genin, G. M. (September 27, 2004). "Measurement of Strain in Physical Models of Brain Injury: A Method Based on HARP Analysis of Tagged Magnetic Resonance Images (MRI) ." ASME. J Biomech Eng. August 2004; 126(4): 523–528. https://doi.org/10.1115/1.1785811
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