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 B549Z
Ultrasonography of Inferior Vena Cava
Ultrasonography of Inferior Vena Cava, Intravascular
Ultrasonography of Inferior Vena Cava, Guidance