RSNA Logo Statistics claim that annually 795,000 Americans suffer a new or recurrent stroke and the following study can help reduce this number. A latest study asserts that magnetic resonance imaging (MRI) of the brain can anticipate the time of stroke onset. Patients with an acute ischemic stroke can therefore be given the tissue plasminogen activator, or tPA drugs that dissolve blood clot and restore blood flow well in time.

A major issue of this clot-busting drug appears that its administration can only be done within four and a half hours of the onset of a stroke. If the medication is provided beyond that window of time it possibly leads to bleeding in the brain. While conducting the study, investigators reviewed data from consecutive patients with acute ischemic stroke treated at Sainte-Anne Hospital in Paris between May 2006 and October 2008. The time of stroke onset was well defined and each patient had gone through MRI within 12 hours.

The study initiated on 130 patients had 77 men and 53 women with a mean age of 64.7 years. While 63 patients underwent MRI within three hours of stroke onset, 67 were imaged between three and 12 hours after stroke onset. Catherine Oppenheim, M.D., Ph.D., professor of radiology at Université Paris Descartes in France, lead author of the study and colleagues examined the various types of MRI data on the patients, including fluid-attenuated inversion recovery (FLAIR), diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) ratios.

Having evaluated the MRI data, radiologists were probably able to predict with more than 90 percent accuracy which patients had experienced stroke symptoms for longer than three hours. If the time of stroke onset is unknown, MRI supposedly aids in distinguishing people who have higher chances within the three-hour time window when tPA is proven effective and approved for use. Due to the duration of a stroke ascertained by MRI, stroke may be managed urgently in the emergency setting.

The study will be published online and in the December issue of the journal Radiology.