The rotational acquisitions can either be encoded as XA Image or as Enhanced XA Image. The two XA instances (let's call them "C1" and "C2") are encoded in two different Series ("B1" and "B2") of the same Study ("A").

The volume data is encoded as two X-Ray 3D Angiographic instances ("Z1" and "Z2"). The volumes are typically a full set (in number of rows, columns and slices) of the projected matrix size (in number of rows and columns).

Each reconstructed volume contains one acquisition context consisting of all the frames of the corresponding source 2D XA Image. To display the two volumes together, they share the same Frame of Reference UID.