Abstract
In the collaborative study of the Prospective Investigation of Pulmonary Embolism
Diagnosis (PIOPED), the validity of ventilation/perfusion lung scans for the diagnosis
of acute pulmonary embolism (PE) was shown. Subsequently, the validity of ventilation/perfusion
scans, using PIOPED data, was shown in patients with normal chest radiographs, patients
with no prior cardiopulmonary disease, in patients with any prior cardiopulmonary
disease, and in patients with chronic obstructive pulmonary disease. Stratification
of patients according to the presence or absence of prior cardiopulmonary disease
was shown to permit an enhanced positive predictive value of PE by applying different
criteria to both groups. Further stratification according to clinical assessment further
enhanced the ability to assess a positive predictive value of PE.
