CT Scans Can Predict Recurrent Stroke When MRI Is Not Readily Available

These critical data can help clinicians determine if stronger medications should be used to prevent future episodes, or if a patient can be safely sent home.

Currently, clinicians can use a brain magnetic resonance imaging (MRI) scan to predict if a TIA patient is at high risk for a second stroke. Unfortunately, however, MRI units are not immediately available for most of Canada’s population. In most centers, including rural hospitals, CT scans are readily available. This study, conducted by investigators from the University of Calgary’s Hotchkiss Brain Institute (HBI; Canada), sought to determine whether a CT scan would be as effective at predicting stroke risk as MRI.

“Many physicians may not have access to an MRI machine to see what is happening in the brain,” said Dr. Shelagh Coutts, a member of the HBI, associate professor in the department of clinical neurosciences and lead author of the study. “Therefore, this study could allow medical interventions to be more widely available than in just the specialized centers that have access to MRI.”

In order to evaluate stroke risk, Dr. Coutts and colleagues used an injection of dye to visualize the blood vessels from the heart all the way to the brain. This modality is called a CT angiogram, which can easily be administered as part of a routine CT scan. The researchers discovered that patients who had evidence of blockages or narrowed vessels on their CT scans were at high risk for a recurrent stroke. Furthermore, they found that the CT angiogram scan was able to predict the recurrence of stroke with the same accuracy as an MRI.

Shirley Christensen, aged 79, suffered an episode of transient speech disturbance and was diagnosed with a TIA. She was able to identify the onset of her symptoms and sought medical help. Clinicians at the Foothills Medical Centre’s Calgary Stroke Program were able to use a CT scan to determine that her risk of another stroke was very low and she was released from hospital. “I am glad I was able to be released and come back at a later date for an MRI scan,” she remarked. Earlier, physicians would have admitted her to hospital for additional study. This work allows low-risk patients to be managed safely at home instead of being admitted to hospital, which has the added benefit of reducing strain on the healthcare system.

“Even in centers that have MRI machines, there are often delays in getting patients into a scan. This research has an immediate impact and lets us use readily accessible tools to help patients,” stated Dr. Coutts.

Related Links:
University of Calgary’s Hotchkiss Brain Institute