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. This finding was interpreted as consistent with the presence of a large intra-atrial thrombus. This thrombus, despite the thrombolytic treatment that followed, was detached and caused cardiac arrest and eventually the death of the patient. Autopsy showed a massive pulmonary embolus. This report suggests, that injecting (99m)Tc-MAA for a lung perfusion study via the central venous line, may result in the early detection of a thrombus, as in this case at the tip of the catheter and this may be life saving for the patient. We have been unable to find in the literature a similar case of a thrombus detected by the iv administration of (99m)Tc-MAA.