Pulmonary artery stenosis resulting in ventilation-perfusion mismatch in a young female.

Pulmonary embolism is a disorder associated with significant morbidity and mortality in which early, accurate diagnosis is imperative. Controversy exists as to whether this disorder is being overdiagnosed or underdiagnosed. Processes other than pulmonary embolism may produce scintigraphic ventilation-perfusion mismatch and alter the diagnostic specificity of this technique in a small but significant subset of patients. We report a case in which pulmonary ventilation-perfusion mismatch was produced by pulmonary vessel stenosis without evidence of embolic disease. Paradoxically, although the specificity in diagnosing pulmonary embolism with scintigraphic techniques has increased markedly, still greater caution must be exercised in order to preserve this specificity.