Analysis of time reduction methods for magnetic resonance elastography of the brain

Magnetic resonance elastography (MRE) uses a phase-contrast MRI technique to image shear wave propagation in tissue followed by the mathematical inversion of the equations of motion governing tissue mechanics to noninvasively image tissue stiffness. This work investigates the impact of various MR sampling strategies designed to reduce acquisition times on the accuracy of MRE inversions. The results indicate that brain MRE data can be significantly truncated while maintaining a mean global stiffness error less than 10%. The results also indicate that brain MRE data can be collected in as few as eight lines of k-space. This degree of data truncation is possible due to the relatively low spatial frequency content and low amplitude of the shear waves observed during brain MRE exams and will facilitate the design of rapid brain MRE protocols for future clinical investigations.