FFF.2.1.2.2.4 Examples

FFF.2.1.2.2.4.1 Image modality sends trigger to the waveform modality

In this example, there are two modalities that are synchronized with an external clock via NTP. The Image Modality acquires three multi-frame images within the same Study and same Series. Simultaneously, the Waveform Modality acquires the ECG non-stop during the same period, leading to one single Waveform SOP Instance on a different Study. The ECG sampling frequency is 300 Hz on 16 bits signed encoding, making up a number of 1500 samples per channel. The first ECG sample is acquired at nominal start time of the ECG acquisition.

The image modality sends a trigger to the waveform modality at the start time of each of the three images. This signal is stored in one channel of the waveform modality, together with the ECG signal.

In this example, there is no UID referencing capability between the two modalities.

[pic]

Figure FFF.2.1-10Example of Image Modality as Source of Trigger

The attributes that define the relevant content in the two different SOP Instances (Enhanced XA and General ECG) are described in the following figure:

ENHANCED XA SOP INSTANCES

Study Instance UID (0020,000D) = UID “A”
Series Instance UID (0020,000E) = UID “B”
Modality (0008,0060) = XA
Synchronization Frame of Reference UID (0020,0200) = 1.2.840.10008.15.1.1
Synchronization Trigger (0018,106A) = SOURCE
Trigger Source or Type (0018,1061) = Imaging System ID
Acquisition Time Synchronized (0018,1800) = Y
Time Source (0018,1801) = Clock System ID
Time Distribution Protocol (0018,1802) = NTP
NTP Source Address (0018,1803) = aaa.bbb.ccc.ddd
SOP Instance UID (0008,0018) = UID “D1”, “D2” and “D3” resp.

GENERAL ECG SOP INSTANCE

Study Instance UID (0020,000D) = UID “E”
Series Instance UID (0020,000E) = UID “F”
Modality (0008,0060) = ECG
Synchronization Frame of Reference UID (0020,0200) = 1.2.840.10008.15.1.1
Synchronization Trigger (0018,106A) = EXTERNAL
Trigger Source or Type (0018,1061) = Imaging System ID
Synchronization Channel (0018,106C) = 1\2
Acquisition Time Synchronized (0018,1800) = Y
Time Source (0018,1801) = Clock System ID
Time Distribution Protocol (0018,1802) = NTP
NTP Source Address (0018,1803) = aaa.bbb.ccc.ddd
SOP Instance UID (0008,0018) = UID “H”

Waveform Sequence (5400,0100)
Item 1 Only one ECG Multiplex Group
>Multiplex Group Time Offset (0018,1068) = 0
>Waveform Originality (003A,0004) = ORIGINAL
>Number of Waveform Channels (003A,0005) = 2
>Number of Waveform Samples (003A,0010) = 1500
>Sampling Frequency (003A,001A) = 300
>Channel Definition Sequence (003A,0200)
Item 1
>Waveform Sample Interpretation (5400,1006) = SS

Figure FFF.2.1-11Attributes when Image Modality is the Source of Trigger

FFF.2.1.2.2.4.2 Waveform modality sends trigger to the image modality

In this example, there are two modalities that are synchronized with an external clock via NTP.

The Image Modality starts the X-Ray image acquisition and simultaneously the Waveform Modality acquires the ECG and analyzes the signal to determine the phases of the cardiac cycles. At each cycle, the waveform modality sends a trigger to the image modality to start the acquisition of a frame. This trigger is stored in one channel of the waveform modality, together with the ECG signal.

The ECG sampling frequency is 300 Hz on 16 bits signed encoding, making up a number of 1500 samples per channel. The first ECG sample is acquired 10 ms after the nominal start time of the ECG acquisition.

In this example, there is no UID referencing capability between the two modalities.

[pic]

Figure FFF.2.1-12Example of Waveform Modality as Source of Trigger

The attributes that define the relevant content in the two different SOP Instances (Enhanced XA and General ECG) are described in the following figure:

ENHANCED XA SOP INSTANCES

Study Instance UID (0020,000D) = UID “A”
Series Instance UID (0020,000E) = UID “B”
Modality (0008,0060) = XA
Synchronization Frame of Reference UID (0020,0200) = 1.2.840.10008.15.1.1
Synchronization Trigger (0018,106A) = EXTERNAL
Trigger Source or Type (0018,1061) = ECG Equipment ID
Acquisition Time Synchronized (0018,1800) = Y
Time Source (0018,1801) = Clock System ID
Time Distribution Protocol (0018,1802) = NTP
NTP Source Address (0018,1803) = aaa.bbb.ccc.ddd
SOP Instance UID (0008,0018) = UID “D”

GENERAL ECG SOP INSTANCE

Study Instance UID (0020,000D) = UID “E”
Series Instance UID (0020,000E) = UID “F”
Modality (0008,0060) = ECG
Synchronization Frame of Reference UID (0020,0200) = 1.2.840.10008.15.1.1
Synchronization Trigger (0018,106A) = SOURCE
Trigger Source or Type (0018,1061) = ECG Equipment ID
Synchronization Channel (0018,106C) = 1\2
Acquisition Time Synchronized (0018,1800) = Y
Time Source (0018,1801) = Clock System ID
Time Distribution Protocol (0018,1802) = NTP
NTP Source Address (0018,1803) = aaa.bbb.ccc.ddd
SOP Instance UID (0008,0018) = UID “H”

Waveform Sequence (5400,0100)
Item 1 Only one ECG Multiplex Group
>Multiplex Group Time Offset (0018,1068) = 10
>Waveform Originality (003A,0004) = ORIGINAL
>Number of Waveform Channels (003A,0005) = 2
>Number of Waveform Samples (003A,0010) = 1500
>Sampling Frequency (003A,001A) = 300
>Channel Definition Sequence (003A,0200)
Item 1
>Waveform Sample Interpretation (5400,1006) = SS

Figure FFF.2.1-13Attributes when Waveform Modality is the Source of Trigger