PROSPECTIVE INVESTIGATION OF PULMONARY EMBOLISM DX II

这是一项多中心合作研究，旨在确定增强螺旋CT(螺旋CT)诊断急性肺栓塞(PE)的敏感性、特异性、阳性预测值和阴性预测值。肺栓塞是一种常见的疾病，但经常未被诊断并致死。肺通气/灌注扫描是最常用的检查方法。然而，在72%的疑似PE患者和57%确诊的PE患者中，它们是非诊断性的。肺血管造影术是目前最权威的诊断方法，但由于发病率、不适感、费用以及社区医院缺乏可获得性，人们对它的使用犹豫不决。增强螺旋CT是一种近乎非侵入性的检查，它通过显示肺动脉血栓的轮廓来提供明确诊断PE的可能性。然而，它在PE的诊断中的作用尚不清楚。尽管螺旋CT还没有得到充分的验证，但许多医院的医生现在将其作为PE的唯一诊断方法，或者作为肺通气/灌注扫描不具诊断性的患者的决定性检查。这可能导致过度治疗或治疗不足，两者都有严重的潜在并发症。螺旋CT在PE诊断中的作用需要准确的评价，本研究将与肺血管造影进行比较。这一建议的优点是：1)从诊断不足造成的生命损失和过度诊断造成的大出血而言，肺栓塞问题的重要性；2)诊断肺栓塞的新技术的潜在适用性，该新技术将得到广泛应用；3)研究团队。非侵入性腿部检查，特别是静脉超声检查，允许根据静脉血栓栓塞症(PE或深静脉血栓形成)、呼吸/灌注肺扫描或下肢加压超声进行治疗的策略。无肺栓塞史、肺血管造影术或无深静脉血栓形成史的患者行高概率肺通气/肺灌注扫描，即可诊断为肺栓塞。静脉超声检测到的深静脉血栓形成可作为PE诊断的替代指标。肺栓塞将通过肺血管造影术或接近正常或呼吸/灌注正常的肺部SCNA来排除，在未经治疗的患者的随访中没有不良后果(即PE或DVT)。对于接受低概率肺通气/灌注扫描的患者，每隔1周进行2次负静脉加压超声检查以排除PE，然后分别进行6个月的无治疗和1周的随访，6个月的无治疗且无PE或DVT复发。该方案与标准诊断策略类似，不会让患者完全为获取数据而承担风险。

This is a multicenter collaborative study to determine the sensitivity, specificity, positive predictive value, and negative predictive value of contrast enhanced spiral computed tomography (spiral CT) for the diagnosis of acute pulmonary embolism (PE). Pulmonary embolism is common, yet frequently undiagnosed and fatal. Ventilation/perfusion lung scans are the most commonly used test. However, they are nondiagnostic in 72 percent of patients with suspected PE, and in 57 percent of patients with proven PE. Pulmonary angiography is the currently definitive diagnostic test, but there is hesitancy to use it because of morbidity, discomfort, cost, and lack of availability in community hospitals. Contrast enhance spiral CT is a nearly noninvasive test that offers the possibility of a definitive diagnosis of PE by showing the outline of the thrombus in a pulmonary artery. However, its utility in the diagnosis of PE is unknown. Even though spiral CT has not been adequately validated, physicians at many hospitals now use it as a definitive and only diagnostic test for PE, or as a definitive test in patients in whom the ventilation/perfusion lung scan is nondiagnostic. This could lead to overtreatment or undertreatment, both of which have serious potential complications. The role of spiral CT in the diagnosis of PE requires an accurate evaluation which will be made in this investigation by comparison with pulmonary angiography. The strengths of this proposal are: 1) the importance of the problem of PE in terms of lives lost from underdiagnosis, and major bleeding from overdiagnosis 2) the potential applicability of a new technology for the diagnosis of PE that will have widespread availability and 3) the investigator team. Noninvasive leg tests, particularly venous ultrasonography, permit a strategy of management by treatment on the basis of venous thromboembolic disease (PE or deep venous thrombosis), ventilation/perfusion lung scan, or compression ultrasound of the lower extremities. Pulmonary embolism will be diagnosed on the basis of a high probability ventilation/perfusion lung scan in patients with no prior PE, pulmonary angiography, or compression ultrasound of the lower extremities in patients with no prior deep venous thrombosis. Deep venous thrombosis detected by venous ultrasound will serve as a surrogate for the diagnosis of PE. Pulmonary embolism will be excluded by pulmonary angiography, or a nearly normal or normal ventilation/perfusion lung scna with no adverse outcome (i.e. PE or DVT) on follow-up of untreated patients. Among patients with a low probability ventilation/perfusion lung scan, PE will be excluded by 2 negative venous compression ultrasound studies at 1 week intervals followed by 6 months of follow-up with no treatment and at 1 week intervals, followed by 6 months of follow-up with no treatment and no recurrent PE or DVT. The protocol parallels standard diagnostic strategy, without subjecting the patients to risk entirely for the acquisition of data.