Grant: CIHR New Investigator

Most strokes are caused by a blockage of an artery in the brain. In some stroke patients the symptoms from this blocked artery are mild or even transient. There are around half a million stroke patients who present with transient or mild stroke symptoms every year in North America. In the more severe strokes, clot busting drugs are used to unblock the blocked artery. This drug has a rare but serious side effect of bleeding into the brain and so doctors only use this drug when the symptoms are very severe. Tragically many of these mild patients have a second more severe stroke that leaves them disabled. If we can show which patients with mild deficits are at high risk for a second stroke, then we could target new drugs at patients who are at the highest risk. Mild stroke patients with a blocked blood vessel and damage seen on a brain MRI scan are at high risk for a second stroke. Sadly MRI is not available as an emergency for most of Canada's population. In most centres CT scans are more readily available than MRI. If CT can identify which patients are at risk for a second stroke then many more at risk patients could be identified. In this study we are seeking to show that a CT scan can also predict which patients are at risk for a recurrent stroke. Patients with mild or transient deficits presenting within 24 hours of symptom onset to the emergency room will be enrolled in this study. Patients will have both a CT and a MRI scan completed quickly and the results for each test will be compared against how well the patient does. We will show whether a CT can predict which mild or transient events are going to do badly. It will also allow us to see whether CT or MRI is better in predicting who is going to do badly. By using CT to predict outcome, our work is novel in that it could allow treatments to be more widely available than in just the specialised centres where MRI is available.