99mTc-MAA Pulmonary Scintigraphy in Hereditary Hemorrhagic Telangiectasia.

A 5-year-old boy was admitted due to shortness of breath. Blood gas analysis showed hypoxemia. However, thoracic and abdominal CT, brain MRI, and MR angiography were all normal. A Tc-MAA pulmonary scintigraphy revealed right-to-left shunting of the blood. Further genetic analysis showed the mutations in the activin receptor-like kinase 1 gene, and a diagnosis of hereditary hemorrhagic telangiectasia was made.