Figure HH-1 depicts an example of how the data is organized within an instance of the Segmentation IOD. Each item in the Segment Sequence provides the Attributes of a segment. The source image used in all segmentations is referenced in the Shared Functional Groups Sequence. Each item of the Per-Frame Functional Groups Sequence maps a frame to a segment. The Pixel Data classifies the corresponding pixels/voxels of the source Image.