Grant: Operating Grant

Stroke patients require a rapid and accurate diagnosis to determine their management (i.e. further tests, acute treatment, secondary prevention, etc). Two patient groups that need the most help from brain imaging are those with transient ischemic attack (TIA) and those that wake up with their stroke. Transient ischemic attack (TIA) patients have symptoms that disappear or become minimal within hours and thus many patients and doctors do not deal with TIA urgently. However, standard brain imaging has shown that 1/3 of patients show evidence of permanent brain injury after TIA. TIA should be considered a warning sign as some patients will experience a full blown stroke within the next days to months. Early treatment of TIA patients can reduce the risk of another stroke, but methods are needed to determine which patients would benefit the most from urgent diagnostic workup and treatment. Magnetic resonance imaging (MRI) can be sensitive to early brain injury shortly after stroke. A major limitation is that most stroke imaging groups are still using image resolutions that were common in the 1990s and are likely missing many small, but important, brain lesions. MRI scanners are much more sensitive now and can achieve much better "high definition" pictures, but clinics have mainly used that added sensitivity to save time. Patients who wake up with their stroke symptoms are denied clot-busting therapy since it must be given within 4.5 hours of the stroke but the time of their stroke is unknown (sometime during the night). The goal is to develop brain imaging methods that can better detect the stroke lesions in TIA patients and measure the time when the stroke happened in wake-up patients. We will acquire better pictures of the brain by using 'double strength' MRI that are becoming more common in Radiology clinics. These new brain MRI methods will be tested on patients with TIA and wake up stroke to see if our images provide a better diagnosis than the standard methods.