A University of Calgary-led international study highlights the importance of magnetic resonance imaging (MRI) in helping to diagnose minor stroke and transient ischemic attacks (TIAs) — a temporary period of symptoms similar to those of a stroke which usually lasts only a few minutes and doesn't cause permanent damage. Often called a “mini-stroke,” a TIA can be an impending warning sign of a major, devasting stroke.
The study, Diagnosis of Uncertain-Origin Benign Transient Neurological Symptoms (DOUBT), analyzed patients who experienced a number of symptoms that aren’t always associated with stroke — such as numbness, dizziness, or very short episodes of weakness or difficulty with speech.
Principal investigator Dr. Shelagh Coutts, MD, a neurologist at the Foothills Medical Centre (FMC), a professor in the departments of Clinical Neurosciences, Radiology and Community Health Sciences, and a member of the HBI, says that because the risk of stroke increases after a first TIA, it’s important that physicians are certain of the diagnosis in low-risk cases with non-traditional symptoms.
“If you don't have motor and speech symptoms, the diagnosis is a lot less clear,” explains Coutts. “Patients with numbness, dizziness or difficulty walking may not be diagnosed with a stroke syndrome. Overall, these patients are felt to be at low-risk of having stroke.”
Physicians involved in the study examined patients within eight days of the start of their symptoms. They performed a detailed neurological assessment, took a patient history, made a diagnosis and completed an MRI scan within the first week — followed by a second diagnosis. In 30 per cent of patients in the study, physicians changed their diagnosis based on the MRI scan.
“That's not just to change patients to having a stroke,” says Coutts. “There's also the reverse where we thought they might have had a stroke or TIA but based on a negative MRI scan and other clinical symptoms, we decided it wasn't. For patients whose MRI is negative, knowing they haven’t suffered a TIA can be very reassuring.”
Read more about the DOUBT study, including the trial results published in the journal of JAMA Neurology.