Artifactual Perfusion Defect from a Hypertrophic First Costosternal Articulation

摘要

A 66-year-old man had shortness of breath and a clear chest x-ray. Tc-99m MAA perfusion study revealed a moderate-sized, wedge-shaped defect in the left upper lobe seen on oblique images. Neither the posterior perfusion view, nor the posterior xenon-133 ventilation scan demonstrated the abnormality. However, correlation to a previous chest CT established that this defect was due to a hypertrophic left first costosternal articulation. A confident reading of "normal" was rendered. Awareness of such artifactual causes of perfusion defects is important in the interpretation of radionuclide lung scans.