Comparison of Deformation Patterns Excited in the Human Brain In Vivo by Harmonic and Impulsive Skull Motion.
Jordan D Escarcega, Andrew K Knutsen, Ahmed A Alshareef, Curtis L Johnson, Ruth J Okamoto, Dzung L Pham, Philip V Bayly
Author Information
Jordan D Escarcega: Mechanical Engineering and Materials Science, Washington University, 1 Brookings Drive, MSC 1185-208-125, St. Louis, MO 63130. ORCID
Andrew K Knutsen: Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD 20817.
Ahmed A Alshareef: Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD 20817. ORCID
Curtis L Johnson: Biomedical Engineering, University of Delaware, Newark, DE 19716.
Ruth J Okamoto: Mechanical Engineering and Materials Science, Washington University, St. Louis, MO 63130. ORCID
Dzung L Pham: Radiology and Radiological Sciences, Uniformed Services University, Bethesda, MD 20814.
Philip V Bayly: Mechanical Engineering and Materials Science, Washington University, St. Louis, MO 63130.
Noninvasive measurements of brain deformation in Human participants in vivo are needed to develop models of brain biomechanics and understand traumatic brain injury (TBI). Tagged magnetic resonance imaging (tagged MRI) and magnetic resonance elastography (MRE) are two techniques to study Human brain deformation; these techniques differ in the type of motion and difficulty of implementation. In this study, oscillatory strain fields in the Human brain caused by impulsive head acceleration and measured by tagged MRI were compared quantitatively to strain fields measured by MRE during harmonic head motion at 10 and 50���Hz. Strain fields were compared by registering to a common anatomical template, then computing correlations between the registered strain fields. Correlations were computed between tagged MRI strain fields in six participants and MRE strain fields at 10���Hz and 50���Hz in six different participants. Correlations among strain fields within the same experiment type were compared statistically to correlations from different experiment types. Strain fields from harmonic head motion at 10���Hz imaged by MRE were qualitatively and quantitatively similar to modes excited by impulsive head motion, imaged by tagged MRI. Notably, correlations between strain fields from 10���Hz MRE and tagged MRI did not differ significantly from correlations between strain fields from tagged MRI. These results suggest that low-frequency modes of oscillation dominate the response of the brain during impact. Thus, low-frequency MRE, which is simpler and more widely available than tagged MRI, can be used to illuminate the brain's response to head impact.
