The Deformable Spatial Registration IOD describes spatial relationships between images in one or more frames of reference via deformation grids and transformation matrices. The deformations and transformations describe to an application how to sample data from one or more Source RCS into the Registered RCS.

The Registered RCS is the Frame of Reference specified within an Instance of this IOD. The IOD may specify that only a subset of the entire Source RCS Frame of Reference is affected by the transformation, by specifying specific frames of image SOP Instances that use the Source Frame of Reference.

The deformation is described as a grid of offset vectors. Each grid element contains 3 values representing offset distances in the X, Y, and Z directions at the center position of the deformation grid element. The relationship between the data being deformed and the deformation grid is purely spatial. Therefore the resolution of the grid is independent of the data being deformed.