Stiffness and Beyond What MR Elastography Can Tell Us About Brain Structure and Function Under Physiologic and Pathologic ConditionsYin, Ziying, PhD*; Romano, Anthony J., PhD†; Manduca, Armando, PhD*,‡; Ehman, Richard L., MD*; Huston, John III, MD*Topics in Magnetic Resonance Imaging: October 2018 - Volume 27 - Issue 5 - p 305–318 doi: 10.1097/RMR.0000000000000178 Review Articles Abstract Author InformationAuthors Article MetricsMetrics Brain magnetic resonance elastography (MRE) was developed on the basis of a desire to “palpate by imaging” and is becoming a powerful tool in the investigation of neurophysiological and neuropathological states. Measurements are acquired with a specialized MR phase-contrast pulse sequence that can detect tissue motion in response to an applied external or internal excitation. The tissue viscoelasticity is then reconstructed from the measured displacement. Quantitative characterization of brain viscoelastic behaviors provides us an insight into the brain structure and function by assessing the mechanical rigidity, viscosity, friction, and connectivity of brain tissues. Changes in these features are associated with inflammation, demyelination, and neurodegeneration that contribute to brain disease onset and progression. Here, we review the basic principles and limitations of brain MRE and summarize its current neuroanatomical studies and clinical applications to the most common neurosurgical and neurodegenerative disorders, including intracranial tumors, dementia, multiple sclerosis, amyotrophic lateral sclerosis, and traumatic brain injury. Going forward, further improvement in acquisition techniques, stable inverse reconstruction algorithms, and advanced numerical, physical, and preclinical validation models is needed to increase the utility of brain MRE in both research and clinical applications. *Department of Radiology, Mayo Clinic College of Medicine, Rochester, MN †Naval Research Laboratory, Washington, DC ‡Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN. Address correspondence to John Huston III, MD, 200 1st St SW # W4, Rochester, MN 55905 (e-mail: firstname.lastname@example.org). The authors disclose no conflicts of interest. Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.