Stroke is the leading cause of morbidity and disability among the aged population around the world, and its incidence is still rising recently. The cerebrovascular diseases can be approximately divided as two types, namely ischemic and hemorrhagic stroke. Their pathophysiological processes and therapeutical strategies are totally different. For hemorrhagic stroke, which takes up about 20% patients with cerebrovascular diseases, there is a lack of valid medical management in the very early stage except surgical hematoma removal. Whereas it's the key management for ischemic stroke to recanalize the occluded artery and restore blood flow before the irreversible brain damage. According the Guidelines for the Prevention of Stroke in Patients with Stroke and Transient Ischemic Attack, intravenous thrombolysis within 3-4.5 hours is highly recommended for acute ischemic stroke patients. The time window of thrombolysis after ischemic stroke is extremely narrow and greatly affected the patients' outcomes.

Despite the efficacious therapy exists, the rate of successful early thrombolysis is still awfully low, especially in the developing countries. Only 3-5% stroke patients can take advantage of the early thrombolysis. There are two major reasons response for such a low successful thrombolysis rate, including the civilian and some first-aid personnel hasn't mastered the timing of thrombolysis therapy for ischemic stroke. That would be improved by propaganda and education of the stroke knowledge. But what's more critical is the difficulty to diagnose the ischemic stroke with the hemorrhagic stroke from the early symptoms and signs. It's with high risk of enlarging the hematoma if the patients with hemorrhagic stroke received the thrombolytic drugs. For this reason, it's hard for the doctors to provide the correct treatment at the first time before imaging examination finished. And the time cost by CT or MRI examination is likely to responsible for missing the narrow time window and poor prognosis of stroke patients. Consequently, seeking for a noninvasive, rapid, portable and inexpensive diagnosis method which can sensitively distinguish the stroke type before CT or MRI examination would be very helpful in treating the ischemic stroke patients. The new method would enable the first-aid personnel to judge the stroke type in the ambulance and decide to apply intravenous thrombolysis or not.

Because of the blockage in the cerebral supply artery, especially the cerebral middle artery which can't be compensated, the blood flow in the corresponding hemisphere would drop sharply among the ischemic stroke patients. Along with decreasing heat from circulatory system, the infracted hemisphere's temperature should drop. The reduced brain temperature influenced the temperature on the ipsilateral forehead according to the data of our animal and preliminary clinical trial. In contrast, the temperature of the ipsilateral hemisphere showed a mild increase among the ischemic stroke patients in our preliminary experiment. That's possibly because the early mitochondrial dysfunction and inflammatory reaction induced by the hematoma. The difference of the temperature tendency on the ipsilateral forehead has a great chance to be an early physical mark. Temperature test could be rapid and noninvasive, making this mark a promising method to help the doctors to distinguish the stroke type in very early stage. Earlier diagnosis of ischemic stroke means earlier thrombolysis and much better prognosis.

In our study, 30 ischemic stroke patients and 30 hemorrhagic stroke patients will be recruited. In the process of recruitment, the patients with acute stroke attack in no more than 4.5 hours will be collected the temperature at the five point without head coverage, including ipsilateral tempora, ipsilateral forehead, galbella, contralateral forehead, and contralateral tempora. Then the stroke would be recruited into the ischemic and hemorrhagic group according to the later CT or MRI results in the hospital. The accuracy and sensibility of early brain temperature in distinguishing stroke type would be tested in comparison with the diagnosis of imaging examination. It should be emphasized that the diagnosis and following treatment should depend on the imaging examination and our brain temperature test is rapid and noninvasive. The therapy of the recruited stroke patients wouldn't be influenced by the trial and should be as usual as the standard therapy.