International Circulation:  Chronic total occlusion (CTO) lesion leads to poor prognosis in CAD patients. How is the prospect of imaging technology in CTO intervention?
　　Dr. Gämperli: That is a very good question since CTO are intrinsically are very difficult lesions to treat and we know that the treatment of these lesions are associated with a high number of complications， peri-interventional morbidty and even mortality. The proper selection of patients that will benefit from revascularisation of CTO is crucial because of the increased risk. Therefore non-invasive imaging techniques are very important particularly in patient with CTO to define the hemodynamic relevance of these lesions and to predict the benefit you will get from opening up the CTO’s.
　　For example in our center in Switzerland， we require proof of ischemia for every patient who undergoes complex CTO procedure and prior to the invasive study. In our center it is a requirement. What we also do now is to combine CT with functional imaging techniques such as SPECT， which as I showed in my presentation really gives the spatial configuration of the CTO vessel， plus the ischemia associated with this lesion and that is very useful to target your intervention. It also gives you information about calcification inside the CTO， which may also be a predictor of success. So this combined non-invasive evaluation prior to the CTO revascularization is a very useful tool to plan your procedure， to reduce contrast and radiation and to have an optimal outcome.
　　《国际循环》：慢性闭塞病变（CTO）导致了冠心病患者的不良转归。影像学技术在CTO干预中的应用前景如何？
　　Gämperli博士：这是一个非常好的问题，因为CTO本身是治疗起来非常棘手的病变，我们知道CTO治疗的并发症、围术期发病率甚至死亡率都高。正确选择能够从CTO血运重建中获益的患者是至关重要的，因为CTO患者的风险高。因此，无创的影像学检测手段是非常重要的，尤其是用于明确CTO患者病变的血流动力学特点和预测开通CTO能够获得的益处。
　　例如，在瑞士的研究中心，每一位接受复杂CTO操作的患者以及在接受有创检查前都需要有缺血的证据。在我们的中心，这是必须的。我们现在还把CT和功能成像技术（例如SPECT）联合起来应用，我在演讲中提到这样可以显示CTO血管的空间构形，还能显示病变相关的缺血，这对有针对性地进行介入治疗是非常有用的，还会给我们提供有关CTO内部钙化的信息，这可能也是操作成功的预测因素。因此，在CTO进行血运重建之前联合无创检查是规划介入操作的非常有用的工具，可以减少增强显像所带来的辐射，使患者获得最佳转归。