How is the coding of radiological services handled differently from other procedural coding?

1.Many of the subdivisions of the CPT in which cardiovascular codes are found contain notes. Additional parenthetical notes are sometimes included with the codes themselves in this section. Why is it important to pay attention to these notes? What aspects of cardiovascular system procedures make this even more critical than normal?

2.How is the coding of radiological services handled differently from other procedural coding? Why is coding handled in this way?