Researcher(s)
- Melissa Grogin, Neuroscience, University of Delaware
Faculty Mentor(s)
- Curtis Johnson, Biomedical Engineering, University of Delaware
Abstract
Purpose: Magnetic resonance elastography (MRE) is a non-invasive neuroimaging technique that uses low-frequency vibrations to estimate the stiffness of body tissues. Though traditionally used to detect liver fibrosis, MRE is increasingly used to examine structural changes in the brain clinically. Preclinical applications of MRE in in vivo rodent studies have been few, impeding MRE’s role in therapeutic assessment and neurodevelopmental research. MRE has been used successfully to quantify changes to brain white matter stiffness from adolescence to adulthood in a rat model of Fetal Alcohol Spectrum Disorders; however, the applied vibrations were difficult to detect when applied to the adult brain, leading to low quality data. We hypothesized that this was due in part to the integrity of the bite bar apparatus that is used to apply subtle vibrations to the rat’s head while scanning; there might be a loss of vibrational energy from the piezoelectric actuator generating the vibrations to the rat’s head due to the material of the bite bar. To address this issue, we created several custom bite bars made from various materials and collected a series of scans at different frequencies to establish the optimal setup for continued MRE experiments with adult rats. Methods: Female Long-Evans rats (aged 80-150 days) were repeatedly scanned with a 9.4T Bruker scanner while different materials of bite-bar were tested. Bite-bar materials tested included bamboo, carbon filament, fiberglass composite (garolite), and were compared to scans generated using the original plastic bite bar. Results: MRE scans using the carbon filament bit-bar resulted in the highest signal-to-noise ratio, yielding high quality scan data in adult rats. Conclusion: We show that using a custom carbon filament bite bar reliably delivered the most vibrations to the adult rat brain (~ 5um of movement), allowing successful preclinical MRE scanning in rats.