Of all of the variables, dimensions and attributes described here, only the variable MIimage and its dimensions are required to be present in a MINC file. Additional variables, dimensions and attributes may be present in the file -- unrecognised variables and attributes should be ignored.
A word on attribute conventions. All numeric values should be stored in one of the numeric types (NC_BYTE, NC_SHORT, NC_INT, NC_FLOAT or NC_DOUBLE). Some numeric attributes must be specified in a definite unit -- time attributes (such as MIrepetition_time and MIradionuclide_halflife) are given in seconds. Other attributes have an associated attribute that gives the unit -- e.g. MIinjection_dose and MIdose_units.