Amplified MRI and physiological brain tissue motion

Abstract

Brain motion in MRI has historically been viewed as an exasperating source of image artifacts, which give rise to poor image quality posing a diagnostic challenge for radiologists. However, while subtle, these brain motions can reveal important underlying pathophysiology. Even when the body is at rest, the human brain is constantly moving and deforming. With every heartbeat, blood pulsation and cerebrospinal fluid (CSF) motion induce a time varying pressure within the intracranial cavity, causing the brain parenchyma to move and deform. While fluid motion in the brain has been widely studied in both health and disease, there have been comparatively fewer studies on brain tissue motion. There are several noninvasive MRI methods that have been used in the past to capture brain parenchymal motion. Recently, a promising approach has emerged with the advent of amplified Magnetic Resonance Imaging (aMRI). aMRI uses a postprocessing approach to dramatically amplify the motion of the brain due to blood pulsation and CSF motion. With its excellent brain parenchymal/CSF contrast, these aMRI images may assist with our understanding of how altered brain motion relates to underlying brain pathology such as in obstructive brain disorders.