Stein P D, Gottschalk A, Henry J W, Shivkumar K
Henry Ford Heart and Vascular Institute, Detroit.
Chest. 1993 Nov;104(5):1461-7. doi: 10.1378/chest.104.5.1461.
A categorical diagnosis of "high probability" or "intermediate probability" encompasses a spectrum of diagnostic probabilities of pulmonary embolism (PE) that is not communicated to the referring physician. The diagnostic value of ventilation/perfusion lung scans, in the present investigation, was strengthened by use of a table to determine the likelihood of PE in individual patients on the basis of the observed number of mismatched segmental equivalent perfusion defects. In addition, we tested the hypothesis that stratification of patients according to the presence or absence of prior cardiopulmonary disease may enhance the ventilation/perfusion scan assessment of the probability of PE among both of these clinical categories of patients. Data were derived from the collaborative study of the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED). Ventilation/perfusion lung scans were evaluated in 378 patients with acute PE and 672 patients in whom suspected PE was excluded. Among patients with no prior cardiopulmonary disease, > or = 1.0 mismatched segmental equivalents was indicative of PE in 102 of 118 (86 percent) vs 113 of 155 (73 percent) among patients with prior cardiopulmonary disease (p < 0.02). Among patients with prior cardiopulmonary disease, > or = 2 mismatched segmental equivalents were required to indicate > or = 80 percent probability of PE. Stratification on the basis of the presence or absence of prior cardiopulmonary disease, therefore, enhanced the ability of ventilation/perfusion scan readers to assign an accurate positive predictive value and specificity to individual patients based on the observed number of mismatched segmental equivalent defects. Among patients with no prior cardiopulmonary disease, fewer mismatched segmental equivalent defects were required to indicate a high probability of PE than were required by PIOPED criteria. The findings from some of these patients, by PIOPED criteria, would have indicated intermediate probability. Some indeterminate probability readings, therefore, will be eliminated among patients stratified with no prior cardiopulmonary disease.
“高概率”或“中等概率”的分类诊断涵盖了一系列肺栓塞（PE）诊断概率，而这并未传达给转诊医生。在本研究中，通过使用表格根据观察到的不匹配节段等效灌注缺损数量来确定个体患者发生PE的可能性，增强了通气/灌注肺扫描的诊断价值。此外，我们检验了这样一个假设，即根据有无既往心肺疾病对患者进行分层，可能会提高通气/灌注扫描对这两类临床患者中PE概率的评估。数据来源于肺栓塞诊断前瞻性研究（PIOPED）的合作研究。对378例急性PE患者和672例排除疑似PE的患者进行了通气/灌注肺扫描评估。在无既往心肺疾病的患者中，≥1.0个不匹配节段等效物提示PE的有118例中的102例（86%），而在有既往心肺疾病的患者中为155例中的113例（73%）（p<0.02）。在有既往心肺疾病的患者中，需要≥2个不匹配节段等效物才能提示PE概率≥80%。因此，根据有无既往心肺疾病进行分层，增强了通气/灌注扫描阅片者根据观察到的不匹配节段等效缺损数量为个体患者准确分配阳性预测值和特异性的能力。在无既往心肺疾病的患者中，提示PE高概率所需的不匹配节段等效缺损比PIOPED标准要求的少。根据PIOPED标准，这些患者中的一些患者的结果将提示中等概率。因此，在无既往心肺疾病分层的患者中，一些不确定概率的读数将被消除。
