When Image Type (0008,0008) Value 3 is BIPLANE A or BIPLANE B, Referenced Image Sequence (0008,1140) shall be used to identify the corresponding SOP Instance of the Biplane acquisition. In this case, either:
only a single item shall be present, or
multiple items may be present, each with the Purpose of Reference Code Sequence (0040,A170) present, and only the first item having the Purpose of Reference value (121314, DCM, “Other image of biplane pair”).
The Referenced Frame Number (0008,1160) attribute shall not be present in the Item that references the corresponding SOP Instance of the Biplane acquisition.