<International Circulation>：So I have two follow-up questions. What determines which patients receive imaging or not? Do all patients receive imaging? And the second question is what is it when you look at these images that determine what patients will be continued on with treatment after the four-point-five hours?

　　《国际循环网》：我还有2个这方面研究相关的问题，一是，如何决定哪些患者行影像学检查？是否每个患者都要行影像学检查？另一个问题是，当你看到影像学结果时，让你决定在4.5小时后继续治疗的标准是什么？

　　Kaste Markku：After four-point-five hours if there has core infarction and it has to be quite small and then there is the perfusion effect. It is a large systemic territory which has not yet been touched which is probably going to die within the next few hours. There is still brain tissue， systemic tissue which can be resuscitated. It probably can be saved after a certain amount of time. That’s the problem with these on-going trials that if already 6， 7， 8 hours have gone， most of the patients  don’t have much more that can be saved. But there are ongoing trials， one of which is called EXTENT (Extending the Time for Thrombolysis in Emergency Neurological Deficits) which deals with modern imaging and use alteplase the ordinary track with the FDA for example. They try to use this ordinary treatment and in highly selective patients but with similar imaging technology but with different molecules. It’s about a hundred thousand times more effective. (Talking about desmoteplase). (8:30). The good thing about these compounds， alteplase and desmoteplase， is that they are by Mother Nature all molecules. Each of us， you and me， has alteplase in all our arteries. If there is thrombolysis in a place where it should not be Mother Nature gets rid of it by using our own alteplase. And we naturally have an even more effective molecule called desmoteplase. So in a way I believe in these kinds of molecules that have been around for millions or hundreds of millions of years. They are not new comers.

　　Kaste Markku：4.5小时后如果核心梗死区很小，再灌注会有效果。核心梗死区周围为大片未完全梗死区，但再过几小时可能会梗死，这些区域里可能仍有可被再灌注的有极大存活可能性的脑组织。这是目前很多正在进行试验的问题所在，如果6、 7、8小时后，大多数患者可存活脑组织将不多。其中正在进行EXTENT（Extending the Time for Thrombolysis in Emergency Neurological Deficits）试验，应用现代成像技术和FDA批准的常规药（如alteplase），使用常规疗法，严格筛选患者，使用相同的成像技术和不同的治疗药物。有些药物（如desmoteplase）有效性比其它药物好很多，这些药物（如alteplase和 desmoteplase）都是纯天然物质。我们动脉里都有alteplase。如果在一处不能溶栓，可以利用我们自身的alteplase溶栓，而且我们本身还有一个更有效的溶栓分子desmoteplase。因此，在某种意义上来说，这些分子已存在上百万年，并非新生事物。