Ventilation/Perfusion Scan in Pulmonary Embolism

One of the most difficult diagnoses to make in medicine today is that of pulmonary embolic disease. In a study done in the early 1970s,1evidence of pulmonary embolism at autopsy correlated poorly to antemortem diagnosis of pulmonary embolic disease; in only one third of cases were emboli correctly identified. A batting average of.333 may be terrific for a professional baseball player, but for a physician attempting to make a diagnosis of a potentially lethal disease, such a statistic is unsatisfactory. In this week's issue ofThe Journal, an investigation of major importance, giving us information on the sensitivity and specificity of ventilation/perfusion scans in pulmonary embolism, is published.2Nearly all patients with acute pulmonary embolism had abnormal scans (high, intermediate, or low probability), but so did most patients without emboli (sensitivity, 98%; specificity, 10%). This study of more than 900 patients shows that the sensitivity of this