C.6.2 Channel Definition

The Waveform Module Channel Definition sequence attribute (003A,0200) is defined in harmonization with the HL7 Channel Definition (CD) Data Type, in accordance with the following Table. Each Item in the Channel Definition sequence attribute corresponds to an OBX Segment of subtype CHN.

Table C.6-1Correspondence Between DICOM and HL7 Channel Definition

DICOM Attribute HL7 CD Data Type Component
Waveform Channel Number (003A,0202) Channel Identifier (number&name)
Channel Label (003A,0203)
Channel Source Sequence (003A,0208) Waveform Source
Channel Source Modifier Sequence (003A,0209)
Channel Sensitivity (003A,0210) Channel Sensitivity and Units
Channel Sensitivity Units Sequence (003A,0211)
Channel Sensitivity Correction Factor (003A,0212) Channel Calibration Parameters
Channel Baseline (003A,0213) (correctionfactor&baseline&timeskew)
Channel Time Skew (003A,0214)
[Group] Sampling Frequency (003A,001A) Channel Sampling Frequency
Channel Minimum Value (5400,0110) Minimum and Maximum Data Values
Channel Maximum Value (5400,0112) (minimum&maximum)
Channel Offset (003A,0218) not defined in HL7
Channel Status (003A,0205)
Filter Low Frequency (003A,0220)
Filter High Frequency (003A,0221)
Notch Filter Frequency (003A,0222)
Notch Filter Bandwidth (003A,0223)

In the DICOM information object definition, the sampling frequency is defined for the multiplex group, while in HL7 it is defined for each channel, but is required to be identical for all multiplexed channels.

Note that in the HL7 syntax, Waveform Source is a string, rather than a coded entry as used in DICOM. This should be considered in any transcoding between the two formats.