Identification of multilevel right-to-left shunting in a dog using nuclear scintigraphy imaging.

A 27-month-old male neutered French bulldog that was originally diagnosed with tricuspid valve dysplasia and a bidirectional shunting patent foramen ovale was evaluated for progressive polycythemia and exertional cyanosis. There was a high clinical suspicion for a right-to-left shunting patent ductus arteriosus, but given the presence of agitated saline within the left atrium, left ventricle, ascending aorta, and abdominal aorta from the previously diagnosed bidirectional shunting patent foramen ovale, a definitive diagnosis could not be made. The use of dynamic and static nuclear scintigraphy imaging using technetium-labeled macroaggregated albumin (99mTc-MAA) allowed a definitive diagnosis to be made in this animal with multilevel right-to-left shunting as well as quantifying the severity of the right-to-left shunt in a minimally invasive and cost-effective manner.