A large intra-atrial thrombus detected during a lung perfusion scan with technetium-99m macroaggregated albumin injected through the subclavian venous line.

A sixty five year old female patient carrying a double lumen subclavian catheter, with severe right-sided heart failure, was subjected to lung perfusion scan in order to rule out pulmonary embolism. Administration of Tc-99m macroaggregate albumin ((99m)Tc-MAA), via a double lumen (Hickman) subclavian line, resulted in trapping almost half of the injected dose in the right atrium, at the tip of the subclavian catheter. There was no evidence of pulmonary embolism.