Using the CTP DicomPixelAnonymizer
The CTP DicomPixelAnonymizer is a pipeline stage that modifies regions of pixels in a DICOM image. It is configured with a script file that specifies which regions are to be modified, based on information in the non-pixel part of the DICOM dataset. This article describes how to use the DicomPixelAnonymizer to best advantage. The intended audience for this information is clinical trial coordinators at principal investigator sites.
Tthe DicomPixelAnonymizer can modify any uncompressed DICOM image. It can also modify compressed images that have the JPEGBaselilne transfer syntax (1.2.840.10008.1.2.4.50).
For uncompressed images, the stage's test attribute specifies whether to replace modified regions with black or mir-gray, the latter typically used during initial configuration to make it clear which regions are being modified.
For JPEGBaseline images, the stage modifies the internal compressed values directly, thus avoiding the requirement to decompress the image and subsequently recompress it, with the accompanying loss of quality. The effect is a blurring of the regions that renders them unintelligible.
Here are the effects on a sample image that is encoded as JPEGBaseline. This is the original image:
This is the result of decompressing the original image to obtain an uncompressed version and then processing it with the test attribute set to yes:
This is the result of decompressing the original image to obtain an uncompressed version and then processing it with the test attribute set to no:
This is the result of processing the original image without decompression: