HOW TO: Create and save a Region of Interest in a DICOM Image using a presentation state file

#1 Posted : Tuesday, June 4, 2019 2:05:13 PM(UTC)

Hadi

Groups: Manager, Tech Support, Administrators
Posts: 218

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Attached is a sample Winforms project that uses the Leadtools.Dicom and Leadtools.MedicalViewer libraries to create a Presentation State file containing a Region of Interest that can be saved and reloaded.

To initialize the Presentation state file, a new DicomDataSet has to be created and the relevant tags from the loaded DICOM file is brought over:

Code:

      void InitPre()
      {
         if (preDs == null)
         {
            preDs = new DicomDataSet();
            preDs.Reset();
            preDs.Initialize(DicomClassType.ColorSoftcopyPresentationState, DicomDataSetInitializeFlags.AddMandatoryElementsOnly | DicomDataSetInitializeFlags.AddMandatoryElementsOnly | DicomDataSetInitializeFlags.ExplicitVR);
            preDs.AddPresentationStateImageReference(ds, null, 0);
            preDs.InsertElementAndSetValue(DicomTag.PatientID, ds.GetStringValue(ds.FindFirstElement(null, DicomTag.PatientID, false), 0));
            preDs.InsertElementAndSetValue(DicomTag.SeriesInstanceUID, GenerateNewUid("1.2.840.114257.1.1"));
            preDs.InsertElementAndSetValue(DicomTag.StudyInstanceUID, ds.GetStringValue(ds.FindFirstElement(null, DicomTag.StudyInstanceUID, false), 0));
            preDs.InsertElementAndSetValue(DicomTag.SOPInstanceUID, GenerateNewUid("1.2.840.114257.1.1"));
         }
      }

Once the user adds a Region to the MedicalWebViewer using MedicalViewerActionType of PolygonRegion (or any other shaped region) a 1-bit mask is created and saved into the OverlayImage of the image in the DICOM file.

Code:

void UpdateOverlay(RasterImage overlayImage)
      {
         cell.Image.SetOverlayImage(0, overlayImage, RasterGetSetOverlayImageMode.Copy);

         var attributes = cell.Image.GetOverlayAttributes(0, RasterGetSetOverlayAttributesFlags.Flags | RasterGetSetOverlayAttributesFlags.Origin | RasterGetSetOverlayAttributesFlags.Color | RasterGetSetOverlayAttributesFlags.Dicom);
         attributes.AutoProcess = true;
         attributes.AutoPaint = true;
         attributes.BitsAllocated = 1;
         attributes.Type = "R";
         attributes.Origin = LeadPoint.Create(0, 0);
         attributes.Description = "ROI Overlay";
         attributes.Rows = overlayImage.ImageHeight;
         attributes.Columns = overlayImage.ImageWidth;
         attributes.ImageFrameOrigin = 1;
         attributes.FramesInOverlay = cell.Image.PageCount;

         attributes.Color = new RasterColor(0, 255, 255, 255);

         overlayImage.UpdateOverlayAttributes(0, attributes, RasterGetSetOverlayAttributesFlags.Flags | RasterGetSetOverlayAttributesFlags.Origin | RasterGetSetOverlayAttributesFlags.Color | RasterGetSetOverlayAttributesFlags.Dicom);

         preDs.AddPresentationStateImageReference(ds, null, 0);
         preDs.SetOverlayAttributes(0, attributes, DicomSetOverlayFlags.None);
         preDs.SetOverlayImage(0, overlayImage);
      }

Once the region is set, it is saved to the file:

Code:

  
         SaveFileDialog dlg = new SaveFileDialog();
         dlg.Filter = "Pre | *.pre";
         if (dlg.ShowDialog() == DialogResult.OK)
            preDs.Save(dlg.FileName, DicomDataSetSaveFlags.None);

Then it can be reloaded at a later date by the following:

Code:

         OpenFileDialog dlg = new OpenFileDialog
         {
            Filter = "DICOM Pre Files (*.pre)|*.PRE"
         };
         if (dlg.ShowDialog() == DialogResult.OK)
         {
            InitPre();
            preDs.Load(dlg.FileName, DicomDataSetLoadFlags.None);
            if (preDs.OverlayCount > 0)
            {
               overlayImage = preDs.GetOverlayImage(0);
               cell.Image.AddMaskToRegion(null, overlayImage, RasterRegionCombineMode.Set);
               cell.Invalidate();
            }
         }

File Attachment(s):

RegionOfInterestDemo.zip (13kb) downloaded 62 time(s).

Hadi Chami
Developer Support Manager
LEAD Technologies, Inc.


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HOW TO: Create and save a Region of Interest in a DICOM Image using a presentation state file