Table C.220.127.116.11.24-1 specifies the attributes of the Image Data Type Functional Group macro.
Table C.18.104.22.168.24-1 IMAGE DATA TYPE MACRO
|Attribute Name||Tag||Type||Attribute Description|
|Image Data Type Sequence||(0018,9807)||1||Identifies the data type characteristics of this frame. Only a single Item shall be included in this sequence.|
|>Data Type||(0018,9808)||1||Identification of the data type of a frame. See C.22.214.171.124.24.1 for Defined Terms and further explanation.|
|>Aliased Data Type||(0018,980B)||1||Indicates whether this data type is “aliased”. Enumerated Values: YES = data are aliased values NO = data are not aliased values See C.126.96.36.199.24.2 for further explanation.|
C.188.8.131.52.24.1 Data Type
Data Type (0018,9808) indicates the data type of an image frame. Table C.184.108.40.206.24.1-1 lists Defined Terms for this value.
DATA TYPE DEFINED TERMS
|Defined Term Name||Defined Term Description|
|TISSUE_INTENSITY||Tissue intensity typically displayed as grayscale (e.g. B-mode)|
|TISSUE_VELOCITY||Velocity (Doppler shifts) of tissue|
|FLOW_VELOCITY||Velocity (Doppler shifts) of blood flow|
|FLOW_POWER||Power contained in the Doppler signal|
|FLOW_VARIANCE||Statistical variance of blood velocity relative to mean|
|ELASTICITY||Scalar value related to the elastic properties of the tissue|
|PERFUSION||Scalar value related to the volume of blood perfusing into tissue|
|SOUND_SPEED||Speed of sound in tissue|
|ATTENUATION||Reduction in strength of ultrasound signal as the wave traverses through the medium|
C.220.127.116.11.24.2 Aliased Data Type
Some data types require special treatment when interpolating data values whose type is “aliased”, such as FLOW_VELOCITY when derived from discrete data samples as is done for PW Doppler or sampled CW Doppler. Values of these types are “cyclical” in that the maximum value should be considered adjacent to the minumum value in any interpolation algorithm. Aliased Data Type (0018,980B) indicates whether modular arithmetic is necessary for the associated data type.
Note: For example, when Data Type (0018,9808) is FLOW_VELOCITY, Aliased Data Type (0018,980B) should be set to YES indicating that an interpolation algorithm should support aliased data. When several FLOW_VELOCITY values near the maximum or minimum are interpolated, this algorithm should produce a value near the maximum or minimum. It would be incorrect to use an interpolation algorithm such as the arithmetic mean, which would erroneously produce a result near the mid-point of the range.