In a new study, researchers highlighting the importance of magnetic resonance imaging (MRI) in helping to diagnose minor stroke and transient ischemic attacks (TIAs).
The research was led by a team from the University of Calgary.
Because the risk of stroke increases after a first TIA, it is important that physicians are certain of the diagnosis in low-risk cases with unusual symptoms.
Patients with motor or speech symptoms lasting more than five minutes are at high risk of having a stroke and must be seen urgently.
The problem is that over 50%of patients with possible symptoms of a TIA do not have these symptoms.
If this happens, the diagnosis can be less clear—so patients with numbness, dizziness or with difficulty walking may not be diagnosed with a stroke syndrome.
In the study, the scientists examined 1028 patients who experienced a number of symptoms that aren’t always associated with strokes—such as numbness, dizziness, or very short episodes of weakness or difficulty with speech.
They 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 then did an MRI scan within the first week—followed by a second diagnosis.
They found there was a 13% risk of having had a stroke. This was far higher than they expected in this low-risk population.
Further, in 30% of patients in the study, the physicians changed their diagnosis based on the MRI scan.
In many patients with minor stroke or TIA, symptoms are straightforward and a stroke can be diagnosed—or ruled out—without the need for MRI scans.
The MRI is really useful in patients in whom doctors are unclear what the diagnosis is.
And from a patient perspective (if the MRI is negative), knowing they haven’t had a TIA is very important, as it reduces the use of unnecessary medication.
One author of the study is Dr. Shelagh Coutts, MD,
The study is published in the journal JAMA Neurology.
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