Defining Sequence Item for ECG Dicom by Using ClearCanvas Library

Question

I am using clearcanvas library for dicomizing ecg image.

I need to define channel information (channel source sequence and channel sensitivity unit sequence) for each channel which I extract. How do I define each channel in ClearCanvas?

Sample code is below;

channelSeq[i] = new DicomSequenceItem();
channelSeq[i][DicomTags.ChannelBaseline].SetUInt32(0, 0);
channelSeq[i][DicomTags.ChannelTimeSkew].SetUInt32(0, 0);
channelSeq[i][DicomTags.ChannelSampleSkew].SetUInt32(0, 0);
channelSeq[i][DicomTags.WaveformBitsAllocated].SetInt32(0, 16); // 16 bit
channelSeq[i][DicomTags.ChannelSensitivityCorrectionFactor].SetUInt32(0, 1);
channelSeq[i][DicomTags.ChannelSensitivity].SetUInt32(0, 1);
channelSourceSeq = new DicomSequenceItem();
channelSourceSeq[DicomTags.CodeValue].SetStringValue(HttpContext.GetGlobalResourceObject("EcgCodes", ecgType).ToString());
channelSourceSeq[DicomTags.ContextIdentifier].SetStringValue("CID 3001");
channelSeq[i][DicomTags.ChannelSourceSequence].Values = channelSourceSeq;
channelSensUnitSeq = new DicomSequenceItem();
channelSensUnitSeq[DicomTags.CodeValue].SetStringValue("uV"); // millivolt
channelSeq[i][DicomTags.ChannelSensitivityUnitsSequence].Values = channelSensUnitSeq;
channelSeq[i][DicomTags.WaveformChannelNumber].SetStringValue((i + 1).ToString());
channelSeq[i][DicomTags.ChannelLabel].SetStringValue("Channel " + (i + 1));
channelSeq[i][DicomTags.ChannelStatus].SetStringValue("OK");

Thanks for help.

JohnnyQ JohnnyQ · Accepted Answer · 2015-05-06T10:33:36

The Channel Definition Sequence (003A,0200) is a SubSequence within your Waveform Sequence (5400,1000).

There you can add your channels as much as you need, e.g.

channelSeq[i][DicomTags.WaveformChannelNumber].SetStringValue("1");
channelSeq[i][DicomTags.ChannelLabel].SetStringValue("Channel 1");
channelSeq[i][DicomTags.ChannelStatus].SetStringValue("OK");

and add your source and sensitivity like you have shown in your example.

Finally add your items to into Channel Definition Sequence

myWaveFormSequence[DicomTags.ChannelDefinitionSequence].AddSequenceItem(channelSeq[i]);

See further tags what you can specify for a channel sequence at http://dicom.nema.org/medical/dicom/current/output/chtml/part03/sect_C.10.9.html

Defining Sequence Item for ECG Dicom by Using ClearCanvas Library

1 Answers