Sodium and diffusion MRI - a precise method to determine the extent of still viable ischemic stroke tissue
Acute stroke treatment decisions can be improved by accurately identifying still viable (penumbra) tissue. However, it is challenging to separate permanently-damaged (core) from penumbra tissue. While hypoperfusion can be measured sufficiently precise using perfusion weighted imaging (PWI), reduced apparent diffusion coefficient (ADC) – as measured via diffusion weighted imaging (DWI) - was observed clinically and pre-clinically to reverse spontaneously during the acute stroke phase. The salvageable tissue fraction can hence be strongly underestimated. In this talk, the potential of Tissue Sodium Content (TSC) measures using MRI will be discussed. Pre-clinical studies in permanent ischemic stroke (Wetterling, Gallagher, MacRae, Junge, & Fagan, 2012; Wetterling et al., 2015), and acute stroke patients will be presented (Wetterling, Ansar, & Handwerker, 2012). The concept of tissue viability maps as determined from sodium and diffusion MRI data will be introduced. Hence, the diagnostic question of whether tissue is partially dead or still alive at a given point in time may be answered non-invasively in the future, e.g. to inform treatment for stroke or tumor therapy patients.