Acute Pulmonary Thromboembolism: A Historical Perspective

Abstract

639 diographic features of acute pulmonary thromboembolism are insensitive and nonspecific. The Westermark sign—oligemia of the lung beyond the occluded vessel—did not live up to early enthusiasm [10]. Similarly, elevation of the ipsilateral hemidiaphragm, enlargement of the proximal pulmonary artery, atelectasis, and pleural effusion are all nonspecific. The most common radiographic findings in the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) study were atelectasis and patchy pulmonary opacity [11]. However, the prevalence of these findings in patients who did not have pulmonary thromboembolism was not significantly different. Radionuclide imaging (scintigraphy) became the mainstay of noninvasive imaging but had limitations. A normal ventilation–perfusion scan reliably excluded acute pulmonary thromboembolism, and a high-prob ability scan made this diagnosis with reasonable accuracy. However, a substantial proportion of ventilation–perfusion studies were nondiagnostic [12]. Over the years, the introduction of newer, safer, and quicker investigations has led to a progressive decrease in mortality from acute pulmonary thromboembolism [13]. In the early 1990s, the value of CT in the diagnosis of central pulmonary thromboembolism was documented by Remy-Jardin et al. [14]. CT was 90% sensitive and 96% specific for detection of central and lobar pulmonary thromboembolism, but segmental and subsegmental pulmonary thromboembolism was not assessed. In 1995, Goodman et al. [2] significantly advanced the field by comparing helical CT angiography (CTA) with pulmonary angiography in patients with unresolved suspicion for pulmonary thromboembolism and addressing the issue of segmental and subsegmental pulmonary thromboembolism. Acute Pulmonary Thromboembolism: A Historical Perspective