| DICOM PS3.17 2025a - Explanatory Information |
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In clinical neurophysiology it is important to be able to recreate the presentation of the recorded data as it was displayed during the recording or during review and reporting. This allows subsequent reviewers to recreate the display as it was when the recording was made and when an annotation was created, which allows for review of subtle features that may not be obvious in other montages or reference states.
In cardiology, technicians annotate previously recorded waveforms (e.g., from home monitoring Holter ECG) and highlight areas of interest. This information is essential input for the cardiologist who reviews the ECG and finally provides the report.
Waveform objects support limited display information, including only Attributes for color and scaling of waveform channels. This leaves out much information about how waveforms were visualized by the technician who recorded the study, including the mathematical derivation of channels needed for visualization, the ordering of channels on the display screen, and filters used for channel visualization.
In neurophysiology, a montage defines the list of channels for visualization of the waveform data which is created from the originally recorded channel sources and it conveys the method for their mathematical (linear) recombination. Montages could be either predefined (for a common list of sources) and referenced by a montage object identifier or defined for each specific recording, because the recording could include a unique list of sources.
Waveform Annotations are textual or coded markers assigned to a specific timepoint or time range, related to all channels or a selected set of channels. Annotations could be observations of waveforms, patient stimuli, comments about the recording, as well as measurements.
A Waveform Presentation State object stores annotations, visualization filters, and montages used for a given recording (patient related). A Waveform Presentation State object is stored together with the waveform study (e.g., a Routine Scalp EEG recording) and can be exchanged between systems.
The Waveform Acquisition Presentation State object is created during the waveform recording in order to persist the montages and filter settings used by the technologist. Over the course of the waveform recording the technologist may use different montages and filter settings and this information is persisted in the Waveform Acquisition Presentation State object.
The Waveform Presentation State object is created later during review or analysis of the waveform. This persists a description of montages and filter settings associated with created annotations. Subsequent viewers of the recording and the annotations might choose this same view by applying this Presentation State.
A physician acting as a post-hoc reviewer looks through a completed EEG recording and marks potential epileptiform features. The annotations added by the technician during the recording are displayed for anyone reviewing the recording and can provide details useful for the interpreting physician, such as when a patient is moving their body. If the physician adds annotations a Waveform Annotation SR is created. In addition, if triggered by the post-hoc study reviewer, a Waveform Presentation State object is created to store used filter settings and montages.
Use case: Electronic Health Record
An epilepsy patient is treated in another organization and the neurologist wants to see the EEGs and findings of previous epilepsy monitoring recordings (accessible via the patient's health record). Montages and filter settings used during recording and review may be different between hospitals. So the reviewer may decide to use either the Waveform Acquisition Presentation State object to see directly what the outside EEG staff annotated and which filters and montages where used or may choose to review the data with montage settings as provided in a Waveform Presentation State created by the outside neurologist.
Use case: Automated Waveform Analysis
Algorithms may store observations and measurements as annotations in a Waveform Annotation SR object. Additionally, it might be useful to store montages and filter settings used by the algorithm in a Waveform Presentation State object for future reference.
| DICOM PS3.17 2025a - Explanatory Information |
|---|