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 B535Z
Magnetic Resonance Imaging (MRI) of Bilateral Jugular Veins
MRI of Bi Jugular Vein using Oth Contrast
MRI of Bi Jugular Vein using Oth Contrast, Unenh, Enhance