File block size:
     Header block: 24 Bytes
     Information Object Pointer (IOP): 24 Bytes
     Information Object Block (IOB): Variable

File Data Structure:
     Numerical byte order: Most significant byte first (MSB).
     Image pixels per row size restricted to: 4k, 2k, 1k, 512

Header block:
     This block identifies the file type, version number, file name, number of information object pointers, and the offset, from beginning of file, to the first object pointer.

Information Object Pointer (IOP):
     The IOP defines the data content and the offset from the beginning of file to its

Information Object Block (IOB):
     The IOB contains text and data blocks, such as data maps, data tables, and bitmaps.
 

     Four image file types (Figure 6) are defined; Cross Section, Volume of Interest, Rendered, and Segmented Map, each containing an ASCII text block, and one or more information object blocks. The text block provides narrative information for the file user.. Other data blocks are formatted to support image processing and visualization.

Cross Section file:
     Header: (see prior description)
     Text Block: A written description of anatomical, specimen and image information.
     Label Table: A list of anatomical labels of structures visible within the enclosed bitmaps.
     Coordinate Map: A x,y coordinate map of bitmap locations for the enclosed anatomical labels.
     Image Bitmap: An enclosed cross section image bitmap.

Volume of Interest file:
     Header: (see prior description)
     Text Block: A written description of anatomical, specimen and image information.
     Segment Table: A list of codes which identify enclosed image bitmaps.
     Segment Masks: A set of segmented bytemasks for a specified anatomical structure and substructures.
     ROI Stack: A set of regions from cross section images related to the enclosed bytemasks.

Rendered File:
     Header: (see prior description)
     Text Block: A written description of anatomical, specimen and image information.
     Image Block: A prior rendered image with its file format data(jpeg, tif, gif, etc).

Segmented Map:(This is a pending file type)
     Header: (see prior description)
     Text Block: A written description of anatomical, specimen and Image information.
     Segment Codes: Codes which identify enclosed segmented masks.
     Segment Masks: A set of segmented bytemasks for specified anatomical structures.