Acute Stroke: Imaging the Ischaemic Penumbra with Perfusion CT

中风的负担很大。溶解血栓的药物(溶栓治疗)可以通过疏通受影响的脑动脉，极大地改善许多严重中风患者的预后。然而，很少有患者接受这种药物治疗，因为目前的批准仅限于中风发病后3小时内的治疗。溶栓治疗的主要目的是挽救血流减少的脑组织(缺血半暗带)，使其免受不可逆转的损害(梗塞)。如果脑动脉中的血块不能通过溶解的血块恢复血流，那么在接下来的48小时内，半影区就会逐渐梗死。半影脑组织不能通过临床评估或标准CT扫描来识别。新一代CT扫描仪能够评估脑血流。CT灌注成像(CTP)耐受性好，时间效率高，可以整合到所有中风患者的脑CT扫描过程中。初步证据表明，CTP可以区分代表缺血半暗带的组织和已经永久损伤的组织。本项目旨在验证CTP在脑缺血半暗带成像中的应用。这将基于测试半影区CTP组织信号在预测临床结果和最终卒中大小方面的准确性。这是针对这种相对较新但日益普及的成像技术在全球范围内计划的唯一一项全国性合作研究。通过CTP快速识别脑血流不足但仍可存活的能力，将为中风患者的常规紧急评估增加新的令人兴奋的管理选择。这项独特的研究结果可能会对全球急性中风的管理产生重大影响。如果得到验证，预计CTP将被广泛用于改善中风溶栓患者的选择，特别是安全地延长时间窗口，以便更多的患者能够得到更好的治疗结果。

The burden of stroke is large. Clot-dissolving medication (thrombolysis) may dramatically improve the outcome of many patients with severe stroke by unblocking the affected brain artery. However, very few patients receive this medication, as the current approval is restricted to treatment within 3 hours of stroke onset. The major aim of thrombolysis is to rescue brain tissue with reduced blood flow (the ischaemic penumbra) from becoming irreversibly damaged (infarcted). The penumbra progressively becomes infarcted over the next 48 hours if blood flow is not restored by the blood clot in the brain artery being dissolved. Penumbral brain tissue cannot be identified with clinical assessment or standard CT scanning. New generation CT scanners are capable of assessing brain blood flow. Perfusion CT imaging (CTP) is well tolerated and time-efficient, and can be integrated into the brain CT scanning process performed on all stroke patients. Preliminary evidence suggests that CTP can distinguish between tissue that represents the ischaemic penumbra, and tissue that is already permanently injured. This project aims to validate the use of CTP in imaging the ischaemic penumbra. This will be based on testing the accuracy of CTP tissue signatures of the penumbra in predicting clinical outcome and final stroke size. This is the only national collaborative study planned worldwide for this relatively new but increasingly accessible imaging technique. The ability to rapidly identify under-perfused but still viable brain with CTP would add new and exciting management options to the routine emergency assessment of stroke patients. The results of this unique study could have a significant impact on the management of acute stroke worldwide. If validated, it is anticipated that CTP would be widely used to improve patient selection for stroke thrombolysis, especially in safely extending the time window so that a greater number of patients can be treated with better outcomes.