Hypoxemia in Osler-Weber-Rendu
66 year old female with long-standing polycythemia, found to be hypoxemic on exam (O2 sat 93% on room air). Chest X-ray shows persistent right lung "infiltrates", so a chest CT was performed. There is a history of AV malformations in the brain and colon.
Routine chest CT is straightforward: a large complex AV malformation is seen in the right lower lobe. Feeding artery is 8 mm. There are probable additional multiple tiny AVM's in the lungs. Patient most likely has Osler-Weber-Rendu or hereditary hemorrhagic telangiectasia.
Spectral CT shows shunting of blood from healthy alveoli around the AVM into the low pressure pulmonary venous circulation as a paucity of iodine in the right lower lobe anteriorly. This illustrates the part of the physiology involved in the disease.