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  • TransferSyntax selection for CStore when using CGET

    From istvan@21:1/5 to All on Wed Jan 13 15:23:45 2021
    Hi,
    I implemented C-Get SCP in a DICOM Archive application but I'm not sure how to handle the following situation:
    The DICOM Archive contains MR images , some are in uncompressed format and some are stored in JPEG format. The client DICOM Application (viewer) is capable of handling both uncompressed and JPEG format for these instances.

    When the Client DICOM Viewer issues a C-Get request for some series with MR instances, offers the following Presentation Contexts:
    1 classUID: GETStudyRootQueryRetrieveInformationModel transferSyntaxUID: Implicit VR Endian
    2 classUID: MRImageStorage transferSyntaxUID: Implicit VR Endian, JPEG Lossless

    At the association negotiation phase the DICOM Archive need to pick (select) a single transfer syntax for MRImageStorage. The Presentation Contexts negotiation take place before the C-GET query is resolved and the resulting C-Store operations are
    performed.
    When the transfer syntax selection is performed we do not know the resulting instances. This will lead to possible unnecessary transformations (from uncompressed to JPEG or JPEG to uncompressed) if the selected transfer syntax do not match the format in
    witch the instances are stored in the archive.

    Ideally moving the instances to the client should not require any transformation of the instances (both application supports both transfer syntaxes) but I'm not sure how to achieve this.
    Are the conversion of instances unavoidable in this scenario or I'm missing something related to the DICOM protocol in this case?

    Regards,
    Istvan

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  • From paolo.brandoli@gmail.com@21:1/5 to istvan on Thu Jan 14 02:52:02 2021
    On Thursday, January 14, 2021 at 12:23:47 AM UTC+1, istvan wrote:
    Hi,
    I implemented C-Get SCP in a DICOM Archive application but I'm not sure how to handle the following situation:
    The DICOM Archive contains MR images , some are in uncompressed format and some are stored in JPEG format. The client DICOM Application (viewer) is capable of handling both uncompressed and JPEG format for these instances.

    When the Client DICOM Viewer issues a C-Get request for some series with MR instances, offers the following Presentation Contexts:
    1 classUID: GETStudyRootQueryRetrieveInformationModel transferSyntaxUID: Implicit VR Endian
    2 classUID: MRImageStorage transferSyntaxUID: Implicit VR Endian, JPEG Lossless

    At the association negotiation phase the DICOM Archive need to pick (select) a single transfer syntax for MRImageStorage. The Presentation Contexts negotiation take place before the C-GET query is resolved and the resulting C-Store operations are
    performed.
    When the transfer syntax selection is performed we do not know the resulting instances. This will lead to possible unnecessary transformations (from uncompressed to JPEG or JPEG to uncompressed) if the selected transfer syntax do not match the format
    in witch the instances are stored in the archive.

    Ideally moving the instances to the client should not require any transformation of the instances (both application supports both transfer syntaxes) but I'm not sure how to achieve this.
    Are the conversion of instances unavoidable in this scenario or I'm missing something related to the DICOM protocol in this case?

    Regards,
    Istvan
    The client, instead of offering one presentation context with two transfer syntaxes for the MRImageStorage, should split it into two separate presentation contexts, one with implicit VR endian and one with JPEG lossless so that the archive can accept
    both.

    Best,
    Paolo

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  • From istvan@21:1/5 to All on Mon Jan 18 03:03:56 2021
    Pe joi, 14 ianuarie 2021, la 12:52:04 UTC+2, paolo.b...@gmail.com a scris:
    On Thursday, January 14, 2021 at 12:23:47 AM UTC+1, istvan wrote:
    Hi,
    I implemented C-Get SCP in a DICOM Archive application but I'm not sure how to handle the following situation:
    The DICOM Archive contains MR images , some are in uncompressed format and some are stored in JPEG format. The client DICOM Application (viewer) is capable of handling both uncompressed and JPEG format for these instances.

    When the Client DICOM Viewer issues a C-Get request for some series with MR instances, offers the following Presentation Contexts:
    1 classUID: GETStudyRootQueryRetrieveInformationModel transferSyntaxUID: Implicit VR Endian
    2 classUID: MRImageStorage transferSyntaxUID: Implicit VR Endian, JPEG Lossless

    At the association negotiation phase the DICOM Archive need to pick (select) a single transfer syntax for MRImageStorage. The Presentation Contexts negotiation take place before the C-GET query is resolved and the resulting C-Store operations are
    performed.
    When the transfer syntax selection is performed we do not know the resulting instances. This will lead to possible unnecessary transformations (from uncompressed to JPEG or JPEG to uncompressed) if the selected transfer syntax do not match the format
    in witch the instances are stored in the archive.

    Ideally moving the instances to the client should not require any transformation of the instances (both application supports both transfer syntaxes) but I'm not sure how to achieve this.
    Are the conversion of instances unavoidable in this scenario or I'm missing something related to the DICOM protocol in this case?

    Regards,
    Istvan
    The client, instead of offering one presentation context with two transfer syntaxes for the MRImageStorage, should split it into two separate presentation contexts, one with implicit VR endian and one with JPEG lossless so that the archive can accept
    both.

    Best,
    Paolo

    I was hoping to some solution/approach on the DICOM Archive (C-Get SCP) end. The solution you propose definitely make sense, but the client application is outside of my control.
    I will investigate if the client application offers some configurations related to the way Presentation Contexts are offered in the connection request.
    Thank you for the response.
    Istvan

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  • From =?UTF-8?Q?J=C3=B6rg_Riesmeier?=@21:1/5 to All on Tue Jan 19 08:41:41 2021
    Hi Istvan,

    if the SCP supports the additional Query/Retrieve Attribute Available Transfer Syntax UID (0008,3002), which has been introduced about two years ago with CP-1901 [1], this should also solve your problem.
    Please note, however, that this "new" Attribute is only specified for Instance level queries, and not at the Study or Series level.

    [1] ftp://medical.nema.org/medical/dicom/final/cp1901_ft_cfind_qido_whattransfersyntax.pdf

    Regards,
    Jörg

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