Sodium MRI of Core and Penumbra in ischemic stroke patients

Background and Purpose: Diffusionand perfusion-weighted imaging (DWI/PWI) of acute ischemic stroke can be used to identify the ischemic core (DWI) and to estimate the penumbral tissue (PWI-DWI mismatch) which is at risk of infarction but is potentially salvageable. MRI of sodium, a marker of ionic homeostasis that is disrupted after ischemia, within the lesion may be complementary by indicating regions of irreversible injury or by providing an estimate of stroke onset time, the latter of which could be useful for unknown onset stroke patients. However, while sodium changes in the DWI-defined core have been evaluated previously, the relationship of relative sodium signal intensity to penumbral tissue has not yet been investigated. The purpose of this study is to evaluate tissue sodium in the penumbra and core infarct regions from acute to sub-acute times after stroke.