The Qualifier None is identified by letter "Z" and occupies the 6th position in the ICD10-PCS procedure code structure.
Below a selection of ICD 10 PCS codes related to CT131Z
Planar Nuclear Medicine Imaging of KUB using Iodine 131
Planar Nuclear Medicine Imaging of KUB using Iodine 123
Planar Nuclear Medicine Imaging of KUB using Technetium 99m
Planar Nucl Med Imag of KUB using Oth Radionuclide