Waveform acquisition is part of both the medical imaging environment and the general clinical environment. Because of its broad use, there has been significant previous and complementary work in waveform standardization of which the following are particularly important:
ASTM E31.16 - E1467 Specification for Transferring Digital Neurophysiogical Data Between Independent Computer Systems
CEN TC251 PT5-007 - prENV1064 draft Standard Communications Protocol for Computer-Assisted Electrocardiography (SCP-ECG).
CEN TC251 PT5-021 - draft Vital Signs Information Representation Standard (VITAL)
HL7 Automated Data SIG - HL7 Version 2.3, Chapter 7.14-20
IEEE P1073 - draft Medical Information Bus Standard (MIB)
DICOM - NEMA PS3.3, Section A.10 Standalone Curve Information Object Definition
For DICOM, the domain of waveform standardization is waveform acquisition within the imaging context. It is specifically meant to address waveform acquisitions which will be analyzed with other data which is transferred and managed using the DICOM protocol. It allows the addition of waveform data to that context with minimal incremental cost. Further, it leverages the DICOM persistent object capability for maintaining referential relationships to other data collected in a multi-modality environment, including references necessary for multi-modality synchronization.
Waveform interchange in other clinical contexts may use different protocols more appropriate to those domains. In particular, HL7 may be used for transfer of waveform observations to general clinical information systems, and MIB may be used for real-time physiological monitoring and therapy.
The waveform information object definition in DICOM has been specifically harmonized at the semantic level with the HL7 waveform message format. The use of a common object model allows straightforward transcoding and interoperation between systems that use DICOM for waveform interchange and those that use HL7, and may be viewed as an example of common semantics implemented in the differing syntaxes of two messaging systems.
Note: HL7 allows transport of DICOM SOP Instances (information objects) encapsulated within HL7 messages. Since the DICOM and HL7 waveform semantics are harmonized, DICOM Waveform SOP Instances need not be transported as encapsulated data, as they can be transcoded to native HL7 Waveform Observation format.