Measuring and Validating Skull and Brain Motion in Human Subjects
Between January and March 2020, three human subjects were imaged in a Prisma 3T MRI scanner providing a total of five datasets. Using MR Elastoography (MRE) and an accelerometer array, measurements of skull motion and brain motion were recorded to determine mechanical relationships and further inform on the biomechanics influencing traumatic brain injury (TBI). Three tri-axial accelerometers in a 3D printed holder were held by each subject’s mouth. The subject rested their head on a pneumatic “pillow” actuator inside the MRI scanner. MRE sequences were run in order to measure motion and octahedral shear strain in the subject’s brain due to head vibrations with frequencies of 20 Hz, 30 Hz, 50 Hz, 70 Hz, and 90 Hz. Skull acceleration was simultaneously measured. A diffusion tensor imaging (DTI) sequence was also run for each dataset to examine the microstructure of the brain in combination with the estimated brain motion. Estimates from MRE sequences indicated that with increased actuation frequency, the median bulk translation, bulk rotation, wave motion, and octahedral shear strain of the brain all decrease. Comparison of accelerometer and MRE estimates show a clear link between skull and brain displacement. However, further characterization of the accelerometer set-up in a controlled environment is necessary to more accurately represent motion of the head in response to actuation.
Mechanical Engineering and Material Sciences Independent Study
Date of Submission
Rifkin, Julia K.; Okamoto, Ruth J.; and Bayly, Philip V., "Measuring and Validating Skull and Brain Motion in Human Subjects" (2020). Mechanical Engineering and Materials Science Independent Study. 129.