Question: Oregon Subscriber Answer: Code 75605 (Aortography, thoracic, by serialography, radiological supervision and interpretation) describes visualization of the thoracic (also referred to as the descending aorta), and 75650 (Angiography, cervicocerebral, catheter, including vessel origin, radiological supervision and interpretation) describes an aortic arch study. Your facility will not know what to bill until your cardiologist performs the interpretation. Focus on the documentation: Did your cardiologist describe the origins of the great vessels? You'll see that 75650 includes "vessel origin."