Floating Point Values Attribute
| Tag | (0066,0125) |
|---|---|
| Type | Required (1) |
| Keyword | FloatingPointValues |
| Value Multiplicity | 1 |
| Value Representation | Other Float String (OF) |
Measurement values for points stored in Point Coordinates Data (0066, 0016) of the corresponding track in Track Sequence (0066,0102).
If Track Point Index List (0066,0129) is absent, measurement values are stored for every point in Point Coordinates Data (0066,0016) and the number of values shall match the number and order of points stored in Point Coordinates Data (0066, 0016).
If Track Point Index List (0066,0129) is present, measurement values are stored for a subset of points in Point Coordinates Data (0066, 0016) and the number of values shall match the number and order of point indices in Track Point Index List (0066,0129).
See Section C.8.33.2.1.
Section C.8.33.2.1
C.8.33.2.1 Tractography Results Module Attribute Descriptions
This Module encodes one or more Track Sets, each of which consists of one or more Tracks, each of which is defined by one or more points. For each Track, optionally one or more measurements may be defined, either for every point or a subset of points. Measurements are described by coded type and unit. For each Track and/or Track Set, summary statistics derived from measurements may be included (whether or not the actual measurements are encoded).
When a measurement (i.e., an Item of Measurements Sequence (0066,0121) ) is encoded for every point in a track, then Floating Point Values (0066,0125) contains the corresponding values for every point. When a measurement is encoded for a subset of points, then Floating Point Values (0066,0125) contains measurement values for the points in Point Coordinates Data (0066,0016) which are referenced in Track Point Index List (0066,0129).
More than one Measurements Sequence (0066,0121) Item may be used, for example to encode different types of measurements, such as Fractional Anisotropy (FA) and Apparent Diffusion Coefficient (ADC), or to encode different components of a measurement that is a tuple, e.g., a diffusion tensor. In the latter case, which component, and which tensor, will be identified by the fully pre-coordinated code in the Concept Name Code Sequence (0040,A043).
Within one Track Set the different types of measurements or statistics must be the same for all Tracks within that set (i.e., it is not allowed to store one track to a set that does not contain a measurement of a specific type in case all other tracks within that set do).