Massive Pulmonary Embolism Presenting as Complete Unilateral Absence of Lung Perfusion on Pulmonary Scintigraphy: Correlative Imaging with Angiography and Computed Tomography

The most important application of pulmonary scintigraphy is in the evaluation of patients with possible pulmonary embolism. Classically, the perfusion defects of pulmonary embolism are wedge shaped, pleural based, and tend to affect both lungs randomly in a segmental or subsegmental distribution. The authors describe a patient with rare scintigraphic findings of complete unilateral absence of lung perfusion with normal lung ventilation caused by massive pulmonary embolism associated with activated protein C resistance. Correlative imaging with angiography and computed tomography (CT) is presented, and the differential diagnosis of this rare scintigraphic finding is discussed.