Strokes caused by a clot are described as ischaemic. When patients experience ischaemic strokes they may be eligible for “clot busting” therapy (thrombolysis). Currently thrombolysis has been shown to improve patient outcome after a stroke if administered within the first 4.5 hours after stroke onset. Up to 25% of patients wake up with symptoms of a stroke. This means they have an unknown onset time for their stroke (so called ‘wake up strokes’). With no known onset time, they are ineligible for thrombolysis. This study will investigate how we might determine stroke onset time.
Our aim is to use Magnetic Resonance Imaging (MRI) in patients with a known stroke onset time to work out characteristics of particular sequences that would then give us effectively a ‘stroke timer’. Another way to consider this is that with MRI we are trying to work out how much damage has been done to the brain and if any of this damage is still reversible (tissue viability). This has already been done in an animal stroke model. We would then use this data to help estimate the onset time in those patients who had woken up with their symptoms. If we can prove that we can predict time of stroke onset accurately from an MRI scan, we could then consider thrombolysis or other treatments in patients who have woken up with their strokes (this work would form separate research to this study).