Introduction

The role of functional magnetic resonance imaging (FMRI) in patients with stroke is still in evolution. Most of the MRI advances in stroke to date have focused on improved sensitivity for localizing infarcted tissue, or methods for earlier or more reliable imaging of the ischemic penumbra. This has largely been driven by the desire to better determine pathophysiology, and to improve the utility of thrombolysis and other new therapeutic interventions. However, FMRI cannot directly measure damaged brain tissue. It aims to detect healthy tissue by means of imaging changes in local cerebral blood flow, yoked to regional brain function. This correlative relationship is well defined in healthy brain, but is more complex in ischemic brain complicating the interpretation of FMRI in acute stroke. Hence, it seems unlikely that FMRI will have a role in hyperacute stroke (less than 6 hours) because of problems inherent in the duration of the study and choosing an appropriate activation paradigm in the hyperacute period. It is not surprising that most poststroke studies are in the subacute phase or in the chronic recovery period. In this chapter we will briefly describe the history of FMRI development, outline recent contributions to the understanding of stroke-related brain dysfunction and end with recommendations for future research in stroke using FMRI.

Technical background

Functional magnetic resonance imaging

The first report of the mapping of functional changes in regional human brain function using FMRI was by Belliveau et al.