How to preserve UID while saving DICOM file using SimpleITK?

Question

I am trying to read one single DICOM file using SimpleITK and save it somewhere else. I noticed that Series Instance UID changes regardless of the fact that I am explicitly setting it.

How do I preserve the original UID?

from pathlib import Path
import SimpleITK as sitk

dicom_path = '......'
p = Path(dicom_path)

reader = sitk.ImageFileReader()
reader.SetFileName(str(p))
reader.LoadPrivateTagsOn()

image = reader.Execute()
print('Series Instance UID', image.GetMetaData('0020|000e'))
print('SOP Instance UID', image.GetMetaData('0008|0018'))
image.SetMetaData('0020|000e', image.GetMetaData('0020|000e'))

writer = sitk.ImageFileWriter()
writer.SetFileName(out_folder+case+p.name)
writer.SetUseCompression(False)
writer.Execute(image)

reader = sitk.ImageFileReader()
reader.SetFileName(out_folder+case+p.name)
reader.LoadPrivateTagsOn()

image = reader.Execute()
print('Series Instance UID', image.GetMetaData('0020|000e'))
print('SOP Instance UID', image.GetMetaData('0008|0018'))

Gives two different strings for Series UIDs. SOP UIDs stay the same though:

Series Instance UID 1.3.12.2.1107.5.1.4.74141.30000017013107011409700014483
SOP Instance UID 1.3.12.2.1107.5.1.4.74141.30000017013107011409700014570

Series Instance UID 1.2.826.0.1.3680043.2.1125.1.65790274925978549485969544082687134
SOP Instance UID 1.3.12.2.1107.5.1.4.74141.30000017013107011409700014570

score 3 · Accepted Answer · edited Jun 20 '20 at 09:12

Though I never used the toolkit, the behavior of toolkit is strange. Some of the attributes should be changed if pixel data is modified; SOP Instance UID is most important in that case.

But, in your case, pixel data is not modified. Also, only Series Instance UID is modified; SOP Instance UID is unchanged.

Anyway, toolkit provides a way to preserve the UIDs while writing DICOM dataset. Please refer to KeepOriginalImageUIDOn member for more details.

Self& itk::simple::ImageFileWriter::KeepOriginalImageUIDOn (void)
Use the original study/series/frame of reference.

These methods Set/Get/Toggle the KeepOriginalImageUID flag which get's passed to image file's itk::ImageIO object. This is relevant only for the DICOM file format, configuring the writer to use the information in the image's meta-data dictionary or to create new study/series/frame of reference values.

Definition at line 134 of file sitkImageFileWriter.h.

This will instruct toolkit to keep the original UIDs while writing dataset.

How to preserve UID while saving DICOM file using SimpleITK?

1 Answers1