The patient was a married engineer and father of three. He presented to the emergency room with a global arterial circulation deficit, aphasia, and hemiplegia. An earlier noncontrast CT of the brain had found no signs of hemorrhage. An MR scan revealed a considerable perfusion defect caused by a carotid artery occlusion. He arrived 1.5 hours too late, however, for intravenous tissue plasminogen activator thrombolytic therapy.

“What am I going to do?” said Dr. Howard A. Rowley, chief of neuroradiology at the University of Wisconsin in Madison. “Say ‘Sorry, I can't do anything more, we are going to give you an aspirin and send you to rehab?’ I don't think so.”

Though anecdotal, the account reflects a situation seen daily at both small hospitals and large stroke care centers across the U.S. About 750,000 stroke cases will be diagnosed this year, according to the National Stroke Association. The condition has become a leading cause of death and disability in the U.S. and Europe. But even though intravenous tPA was approved more than a decade ago, only about 4% of patients actually get the drug—mostly those who can make it to the ER within three hours of stroke onset.

“We are not doing very well with this disease,” Rowley said. “Maybe it's time to think outside the box.”

A growing number of recently published studies may be persuading researchers and clinicians about the possibility of identifying salvageable brain tissue beyond the established three-hour window for lytic therapy. Rowley referred to the anecdotal case described above to illustrate this point. His institution's 15-minute MR scanning protocol found a perfusion/diffusion mismatch in the engineer's brain that helped guide further management. The patient underwent intra-arterial therapy and returned home the next day with no neurological deficit.

“It would have been immoral and unethical not to treat this patient, or at least offer him this treatment option. Was that the right thing to do? I don't know, but it was certainly sensible based on what we knew about him and what we knew about opening vessels as late as six hours after occlusion,” Rowley said.

Not everyone agrees with this assessment.