Doctors have come up with a new way to use CT scans to predict whether a patient who has had a minor stroke is likely to have a more severe one.

The new research, published in the journal Stroke, shows a CT (computerised tomography) scan can reveal vital information about a patient who has had a minor stroke – known as a transient ischemic attack – that indicates he or she faces a greater risk of suffering another more severe stroke.

That information can help doctors decide if stronger medications should be used to prevent future episodes, or if a patient can be safely sent home.

The study, by the University of Calgary's Hotchkiss Brain Institute, suggests a new way to enhance current techniques for monitoring minor stroke patients.

Doctors can now use an MRI (magnetic resonance imaging) scan to predict if a stroke patient is at high risk for a second stroke. But MRI machines are not always available, particularly in rural hospitals, where CT scans can be performed.

"Many physicians may not have access to an MRI machine to see what is happening in the brain," said lead author Dr. Shelagh Coutts. "Therefore, this study could allow medical interventions to be more widely available than in just the specialized centers that have access to MRI."

Coutts and colleagues used an injection of dye to visualize the blood vessels from the heart to the brain. The researchers found that patients with blockages or narrowed vessels on their CT scans were at high risk for a recurrent stroke. They also found that the CT scan was able to predict the recurrence of stroke with the same accuracy as an MRI.