8.9 DICOM Image Support and Information

Owned by Miles Skinner (Unlicensed)
Sept 14, 2023
2 min read

Practique 8.2.0-beta supports following DICOM image formats and TransferSyntax variations any DICOM images which are in different format/transfer syntax are not supported in this version of risr/assess.

Image size: We recommend that DICOM images over 100 slices should not used in exams as this can cause slow loading of exams.

Total Exam Size: the system supports a total exam size of 2GB. If you require larger exams than this please contact our service desk. 

Format & bit depth

8bit unsigned RGB

Colour DICOM images are supported in the 8bit variation. Support for this format has not been part of the original scope of DICOM support.

8bit/16bit signed/unsigned MONOCHROME 1 & MONOCHROME 2

Grayscale DICOM images which has been provided by RCR in original Anatomy/Rapid/Complex set of images.

Transfer Syntax (DICOM metadata TransferSyntaxUID, http://www.dicomlibrary.com/dicom/transfer-syntax/ )

1.2.840.10008.1.2.1 - Explicit VR Little Endian

Standard uncompressed DICOM image

1.2.840.10008.1.2.4.70 - JPEG Lossless, Nonhierarchical, First- Order Prediction (Processes 14 [Selection Value 1])

JPEG lossless compressed DICOM image. Images with this TransferSyntax has not been part of the original set of the DICOM images provided to Fry-IT.

RCR JPEG Image support

RCR images are not valid DICOM images.

They do not use valid size element for encapsulated data. The documentation on http://www.dclunie.com/medical-image-faq/html/part6.html#CompressionDICOM  defines it as follows:

Note that the Item and Sequence Delimiter tags have no VR, that the Item Delimiter tag is never used, since Items are required to be of fixed not undefined length, and that the Sequence Delimiter tag is always used, since the Pixel Data is always of undefined length (that is FFFFFFFF) for encapsulated data.

Unfortunately, all provided compressed RCR images (Hn_xxxx) does not use the value FFFFFFFF but actual size.

This confuses all common DICOM tools and we did not find any tool what would work with that DICOM image (tried dcmtk, gdcm).

risr/assess provides support for this format however the support is discovered work as the original set of images didn't contain such images as well as the fact that such images are non-standard DICOM images.