Table 1.

The use of RELAX NG entities to define radiology reporting templates

Entity	Meaning
attribute	Defines an attribute of an element. In the present approach, only the “Report” element has a defined attribute.
choice	Exactly one of the enclosed sub-entities must appear in the report. Analogous to the “radio button” construct in an HTML data entry form.
data	Indicates that the user can enter data values that conform to a specified type such as integer, decimal, or date. Parameters can further limit the range of allowed values.
define	Defines a “block” of grammar, which can be referenced using the “ref” tag.
element	Defines a report element, such as a section heading (“Findings”), a feature to be described (“Heart_size”), or a coded value (“Normal”).
empty	Specifies an “empty” element, that is, one with no sub-elements.
group	Groups sub-elements.
interleave	Indicates that the enclosed entities may appear in any order; otherwise, entities must appear in the order specified by the template.
oneOrMore	The enclosed entities appear one or more times.
optional	Indicates that the enclosed entities may or may not appear in a report. The analogous construct in an HTML data entry form is the checkbox.
ref	Allows one to include a block of grammar by reference; the block of grammar is defined using the “define” tag.
text	Indicates that the user can enter an arbitrary text string (except angle brackets), or nothing at all.
value	Specifies fixed content of an element or attribute.
zeroOrMore	The enclosed entities appear zero or more times.