MRI may help save lives of stroke patients

Washington: In what could revolutionise the emergency treatment for stroke patients, a new study has found that magnetic resonance imaging (MRI)of the sufferer`s brain can accurately predict the time of its onset which is crucial to administering tPA -- the potentially life-saving drug.

Patients suffering from an acute ischemic stroke – in which a blood clot or other obstruction blocks blood flow in the brain -- can be treated with tPA, or tissue plasminogen activator, that dissolves the clot and restores blood flow.

However, the clot-busting drug can only be administered within four and a half hours of the onset of a stroke; when given beyond that window of time, the drug can cause bleeding in the brain.

But researchers at the University of Paris, who detailed their study in the journal Radiology, found that by using MRI radiologists can accurately predict when the patient suffered the stroke and recommend whether he or she can be given tPA.

This could help medicos save thousands of people who die of stroke every year. The condition, which claims 5.7 million lives annually, is the second leading cause of death

"As many as a quarter of all stroke patients cannot be given tPA because they wake up with stroke symptoms or are unable to tell their doctor when their stroke began," said lead researcher Catherine Oppenheim at the University of Paris in France.

"With the use of MRI, all stroke patients could be managed urgently, not just those patients with a known onset of symptoms," she said.

For their study, Dr Oppenheim and her team 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 in all the 130 patients and each underwent MRI within 12 hours. Of those, 63 patients underwent MRI within three hours of stroke onset
and 67 were imaged between three and 12 hours after stroke onset.

The radiologists analysed different types of MRI data on the patients, including fluid-attenuated inversion recovery (FLAIR),diffusion-weighted imaging(DWI) and apparent diffusion coefficient (ADC) ratios.

Using the MRI data alone, the radiologists were able to predict with greater than 90 per cent accuracy which patients had experienced stroke symptoms for longer than three

"When the time of stroke onset is unknown, MRI could help identify patients who are highly likely to be within the three-hour time window when tPA is proven effective and
approved for use," Dr. Oppenheim said.

Using MRI to determine the duration of a stroke would change the way stroke is managed in the emergency setting, she added.

Dr Oppenheim said clinical trials are the next step necessary to validate the use of MRI as a surrogate marker of stroke duration.