Complete Right-to-Left Shunt in Lung Perfusion Scintigraphy

Abstract

Lung scintigraphy was performed to rule out pulmonary embolism in a 37-year-old woman suffering from dyspnea and hypoxemia after routine diagnostics failed to find the underlying disease. Perfusion scans did not show tracer uptake within the lungs despite ventilation scans being unremarkable. Instead, the result suggested a complete right-to-left shunt, which was a conundrum. With the assistance of CT an uncommon congenital vessel aberration turned out to be the cause of this exceptional scintigraphy finding, as well as the yet unexplained hypoxemia.