gdcminfo - Man Page

  -r --recursive          recursive traversal of an input directory
  -d --check-deflated     check if file is proper deflated syntax​.
     --resources-path     Resources path​.
     --md5sum             Compute md5sum of Pixel Data attribute value​.
     --check-compression  check the encapsulated stream compression (lossless/lossy)​.
     --force-rescale    force rescale​.
     --force-spacing    force spacing​.
     --mosaic           dump image information of MOSAIC​.

  -h   --help
         print this help text and exit

  -v   --version
         print version information and exit

  -V   --verbose
         verbose mode (warning+error)​.

  -W   --warning
         warning mode, print warning information

  -E   --error
         error mode, print error information

  -D   --debug
         debug mode, print debug information

GDCM_RESOURCES_PATH path pointing to resources files (Part3​.xml, ​.​.​.)

Using data from gdcmData:

$ gdcminfo gdcmData/012345​.002​.050​.dcm

MediaStorage is 1​.2​.840​.10008​.5​.1​.4​.1​.1​.4 [MR Image Storage]
NumberOfDimensions: 2
Dimensions: (256,256)
Origin: (-85,21​.6,108​.7)
Spacing: (0​.664062,0​.664062,1​.5)
DirectionCosines: (1,0,0,0,0,-1)
Rescale Intercept/Slope: (0,1)
SamplesPerPixel    :1
BitsAllocated      :16
BitsStored         :16
HighBit            :15
PixelRepresentation:1
Orientation Label: CORONAL

Using data from David Clunie datasets:

$ gdcminfo BRTUM001​.dcm

MediaStorage is 1​.2​.840​.10008​.5​.1​.4​.1​.1​.4​.1 [Enhanced MR Image Storage]
NumberOfDimensions: 3
Dimensions: (256,256,15)
Origin: (40,-105,105)
Spacing: (0​.820312,0​.820312,6)
DirectionCosines: (0,1,0,0,0,-1)
Rescale Intercept/Slope: (0,1)
SamplesPerPixel    :1
BitsAllocated      :16
BitsStored         :16
HighBit            :15
PixelRepresentation:1
Orientation Label: SAGITTAL

After compressing a DICOM file (see gdcmconv) using a lossless compression algorithm, it is fairly easy to compare the two files for differences at DICOM attribute level​. However one operation is slightly easier to do: how to make sure the compression was actually lossless ? In this case one could use the –md5sum operation​.

Take an uncompressed DICOM image file:

$ gdcminfo --md5sum SIEMENS_ImageLocationUN​.dcm

The tool return: 0621954acd5815e0b4f7b65fcc6506b1

Now compress this file:

$ gdcmconv --jpegls SIEMENS_ImageLocationUN​.dcm lossless_compressed​.dcm

and then check again the md5sum:

$ gdcminfo --md5sum lossless_compressed​.dcm

The tool return: 0621954acd5815e0b4f7b65fcc6506b1

In some environment one wish to check whether or not the DICOM file is lossless​. It is fairly easy to do that in most cases​. Only on two occasions this is not clear from the sole DICOM Attributes​. When the Transfer Syntax is JPEG 2000 Image Compression (1​.2​.840​.10008​.1​.2​.4​.91) and when the Transfer Syntax is JPEG-LS Lossy (Near-Lossless) Image Compression (1​.2​.840​.10008​.1​.2​.4​.81)​.

In this case, the only solution is to open the Pixel Data element, read the specific JPEG header and check whether or not the JPEG transformation was lossless or not:

$ gdcminfo --check-compression gdcmData/MAROTECH_CT_JP2Lossy​.dcm

The tool returns: “Encapsulated Stream was found to be: lossy”

Pay attention that this tool also checks the Image Lossy Compression attribute (0028,2110)​. This means --check-compression will also returns a value of lossy if a predecessor was found to be lossy compressed​.