The Contrast None is identified by letter "Z" and occupies the 5th position in the ICD10-PCS procedure code structure.
Below a selection of ICD 10 PCS codes related to B304Z
Plain Radiography of L Com Carotid using H Osm Contrast
Plain Radiography of Left Common Carotid Artery
Plain Radiography of L Com Carotid using L Osm Contrast
Plain Radiography of L Com Carotid using Oth Contrast