In this example, the heart rate is 75 beats per minute. As the image is acquired during a period of four seconds, it contains five heartbeats.
The ECG signal is analyzed to determine the R-peaks and to relate them to the angiographic frames. Thus the Enhanced XA image contains information of this relationship between the ECG signal and the frames.
Figure FFF.2.1- 4 Example of ECG information in the Enhanced XA image
The attributes that define the two different SOP Instances (Enhanced XA and General ECG) of this example are described in the figures of the previous example, in addition to the attributes described in the following figures:
ENHANCED XA SOP INSTANCE
|Cardiac Synchronization Technique||(0018,9037)||=||REALTIME|
|Cardiac Signal Source||(0018,9085)||=||ECG|
|Cardiac RR Interval Specified||(0018,9070)||=||800|
|Per-Frame Functional Groups Sequence||(5200,9230)|
|Item i||Frame “i”|
|>Cardiac Synchronization Sequence||(0018,9118)|
|Frame of Reference||Synchronization||C.7.4.2||Specifies that the image acquisition is time synchronized with the ECG acquisition. Will have the same content as the General ECG SOP Instance.|
|Image||Enhanced XA/XRF Image||C.8.19.2||Specifies the date and time of the image acquisition.|
Table FFF.2. 1-13 ENHANCED XA IMAGE FUNCTIONAL GROUP MACROS
|Functional Group Macro||PS 3.3 Reference||Usage|
|Frame Content||C.184.108.40.206.2||Provides timing information to correlate each frame to any externally recorded waveform.|
FFF.220.127.116.11.3.1.1 Synchronization Module Recommendations
This Module is used to document the synchronization of the two modalities.
Table FFF.2.1-14 SYNCHRONIZATION MODULE Recommendations
|Synchronization Frame of Reference UID||(0020,0200)||The UTC Synchronization UID “1.2.840.10008.15.1.1” is used in this case.|
|Synchronization Trigger||(0018,106A)||The value “NO TRIGGER” is used for the case of time synchronization via NTP.|
|Acquisition Time Synchronized||(0018,1800)||The value “Y” is used in this scenario.|
|Time Source||(0018,1801)||The same value as in the related General ECG SOP Instance is used in this scenario.|
|Time Distribution Protocol||(0018,1802)||The value “NTP” is used in this scenario.|
|NTP Source Address||(0018,1803)||The same value as in the related General ECG SOP Instance is used in this scenario.|
FFF.18.104.22.168.3.1.2 Enhanced XA/XRF Image Module Recommendations
This module includes the acquisition date and time of the image, which is in the same time basis as the acquisition date and time of the ECG in this scenario.
FFF.22.214.171.124.3.1.3 Frame Content Macro Recommendations
In this scenario the timing information is important to correlate each frame to any externally recorded waveform.
Table FFF.2.1-15 FRAME CONTENT MACRO Recommendations
|Frame Content Sequence||(0020,9111)|
|>Frame Reference Datetime||(0018,9151)||Exact date and time taken from the synchronized clock.|
|>Frame Acquisition Datetime||(0018,9074)||Exact date and time taken from the synchronized clock.|
FFF.126.96.36.199.3.2 Waveform Object
The ECG recording system will take care of filling in the waveform-specific contents in the General ECG SOP Instance. This section will address only the specifics for attributes related to synchronization.
Table FFF.2. 1-16 Waveform IOD Modules
|IE||Module||PS 3.3 Reference||Usage|
|Frame of Reference||Synchronization||C.7.4.2||Specifies that the ECG acquisition is time synchronized with the image acquisition. Will have the same content as the Enhanced XA SOP Instance. See section FFF.188.8.131.52.3.1.1.|
|Waveform||Waveform Identification||C.10.8||Provides timing information to correlate the waveform data to any externally recorded image.|
FFF.184.108.40.206.3.2.1 Waveform Identification Recommendations
The usage of this module is recommended to relate the acquisition time of the waveform data to the related image(s).
Table FFF.2.1-18 WAVEFORM IDENTIFICATION MODULE Recommendations
|Acquisition Datetime||(0008,002A)||Exact start of the waveform acquisition: taken from synchronized clock.|