MRI data could soon play a major role in determining whether stroke survivors are candidates for tPA therapy.
Neurologists and neurosurgeons caring for patients who have just suffered an acute ischemic stroke may soon need not rely on the memory of the patient, or a witness of the stroke, to determine if he or she is an eligible candidate for treatment with a tissue plasminogen activator (tPA), according to the results of a study to be published in the December issue of Radiology.
Because tPA treatment dissolves clots and restores blood flow, timing of administration is crucial, with those receiving such therapy beyond four and a half hours after the stroke at high risk for bleeding in the brain. Therefore, relying on one’s memory is a risky road. Enter Catherine Oppenheim, MD, PhD, professor of radiology, Université Paris Descartes, France.
"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 Oppenheim. For her study, Oppenheim and colleagues reviewed the data of consecutive patients with acute ischemic stroke who were treated at Sainte-Anne Hospital in Paris between May 2006 and October 2008, for whom onset of stroke was well defined and MRI was conducted within 12 hours. Specifically, of the 77 men and 53 women studied, 63 underwent MRI within three hours of stroke onset, and 67 underwent MRI between three and 12 hours after onset of stroke.
Analyzing MRI data only, radiologists who looked at such things as fluid-attenuated inversion recovery, diffusion-weighted imaging, and apparent diffusion coefficient ratios were able to predict which patients had experienced stroke symptoms for longer than three hours, doing so with greater than 90% accuracy.
"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," Oppenheim said, adding that use of MRI to determine time since stroke onset would change the management of stroke in the emergency setting. "With the use of MRI, all stroke patients could be managed urgently, not just those patients with a known onset of symptoms.”
Is the use of MRIs to detect time since stroke onset something that could be easily implemented into the emergency setting? Would radiologists need special training to determine how much time has passed since the onset of a stroke? How many more patients would be able to benefit from tPA treatment? Tell us what you think. We’d love to get a dialog going on this topic.