Fast 3D Vector Field Multi-Frequency Magnetic Resonance Elastography of the Human Brain

Abstract

Magnetic resonance elastography (MRE) is capable of “palpating” the brain by measuring externally induced intracranial shear waves with high spatial and temporal resolution. Conventional MRE is limited as it either relies on two-dimensional multifrequency wave acquisition or three-dimensional vector field MRE at single frequencies. However, full assessment of spatially resolved viscoelastic constants requires both, the acquisition of full shear wave fields and broad dynamic range MRE at multiple frequencies. We therefore propose fast single-shot MRE at 3 Tesla magnetic field strength combined with continuous wave stimulation and interleaved image slice acquisition. By this protocol, a full three dimensional MRE data set is acquired within 60, which may readily be repeated for multifrequency data acquisition. The feasibility of the method is demonstrated in the brain of one healthy volunteer at 50Hz mechanical excitation frequency. The measured complex modulus values are in agreement with results reported in the literature.