In terms of clinical practice， there are some criteria for choice. If it is a young patient， we will try to VQ scan to avoIC the risks of radiation. If there is a low suspicion of PE with a possibility of an alternative diagnosis， then one would use the CT scan.  This is really a matter of patient indivICualization. The two are safe and efficient， but if the patient has renal failure， contraindications or allergic to iodine contrast agents， then you would go for the VQ. Finally， if the patient has pulmonary comorbICities—like chronic pulmonary obstructive disorder or pneumonia—then you know that the chances of the VQ being nonconclusive are higher. Again， you would prefer to go for a CT scan.
在临床实践方面，有一些选择标准。如果是年轻患者，我们会尽量使用VQ减少辐射风险。如果PE可能性低，又可能存在替代诊断，我们会选择CT。这的确是个体化的问题。两种方法都安全有效，但如果患者有肾衰、CT禁忌证或者对碘对比剂过敏，那么应当使用VQ，最后，如果患者有肺部合并症，如慢性阻塞型肺疾病（COPD）或肺炎，那么VQ无法确诊的几率就更高，应当首选CT检查。
　International Circulation: How do you evaluate risk stratification for patients with PE in terms of management strategy?
《国际循环》:您如何评估PE患者关于管理策略的风险分层？
　Dr. Le Gal: In my center， many patients are treated as outpatients. They are discharged on the day they are diagnosed and go back home on treatment. There are tools that form the basis for this management style. There is the echocardiogram or the biomarkers anti-proBNP or troponin or the clinical scoring systems like PESI score. As of now， there is no clear indication of which one is better than the others. In our center， before many of these tools were developed， we were already treating many of these patients as outpatients on very basic clinical criteria: does the patient need oxygen? Does the patient have someone at home to help as needed? Will he be able to inject low-molecular weight heparin? If there was no worry about the patient being home and no need for oxygen support or high-risk of PE， then the patient would be discharged.
Le Gal：在我的医院里，很多患者在门诊治疗。他们诊断当天就出院回家治疗。治疗方式由诊断工具来决定。这些工具包括超声心动图、生物标志物NT-proBNP或肌钙蛋白、以及临床评分系统如PESI评分。目前还没有确切的证据来说明哪个优于其他工具。在我们医院，这些诊断工具中很多还没出现时，我们已经根据基本的临床标准来决定很多患者在门诊治疗。这些标准包括：患者需要吸氧吗？患者在家有人照顾吗？患者能够注射低分子肝素吗？如果对于患者在家的护理没有顾虑，不需要吸氧，也不是高危PE，那么患者就会出院。
    International Circulation: What makes a high-risk PE?
  《国际循环》:如何判断高危PE？
    Dr. Le Gal: The severe PEs is patients with low blood pressure and need oxygen. These patients would be admitted and consICered for thrombolysis. If patients have comorbICities， such as underlying chronic heart failure， COPD， or respiratory behavior， then we know that the risk for these patients is much higher. With blood thinners， if there is a high-risk of bleeding， then that will put them at high risk as well.
　Le Gal：严重PE是指患者血压低并且需要吸氧。这些患者会住院并且考虑溶栓治疗。如果患者有合并症，如潜在的慢性心衰，COPD或呼吸行为，那么我们就知道这部分患者的风险大大升高。由于患者需要使用抗凝药物，如果存在出血高危，那么也需要将其归入高危。