MRI may help diagnose minor stroke
If you’ve taken a CPR course, you’ve likely heard about the F.A.S.T. mnemonic. The idea is simple: if you see a person with face drooping (F), arm weakness (A), and speech difficulties (S), it’s time (T) to call emergency services as they are likely experiencing a stroke. Yet, not all strokes follow such a particular pattern of symptoms. Some patients may just experience numbness or dizziness, likely because it is only a minor stroke or transient ischemic attack (TIA), which may lead physicians to pursue an alternate diagnosis—and perhaps miss the window of opportunity for early treatment or identify the patient as being at higher risk for a later stroke.
New research in JAMA Neurology, however, suggests that emergency physicians may be able to rely on MRI to help them better identify minor stroke and TIAs. The researchers wanted to establish the frequency of acute infarct detected by diffusion-weighted MRI scans. Across multiple hospital sites, 1,028 patients, 522 females and 506 males, with minor symptoms including nonmotor or nonspeech minor focal neurologic events were given a thorough neurological assessment as well as an MRI within 8 days of symptom onset. The researchers discovered:
- MRI results demonstrated that 139 patients (13.5%) had experienced an acute stroke, much higher than expected in such a low-risk population;
- The MRI results led physicians to revise their final diagnoses in 30% of patients;
- A DWI-positive MRI was associated with a higher risk of recurrent stroke one year later;
- Multivariate modeling showed that older age, male sex, motor or speech symptoms, ongoing symptoms at the time of assessment, and abnormal results for the initial neurological examination were also associated with MRI evidence of stroke.
The researchers concluded that MRI scans can offer predictive value in determining not only whether a person with unclear symptoms has experienced a stroke, but also if they are at higher risk for having one later in time. As such, it should be considered when clinical assessment alone cannot reliably confirm or deny an ischemic episode.