Store Parameters string delimited by character ESC=0x1B (27)

[Mathieu Malaterre]

Dear all,

Could someone possibly from GE Healthcare MR please confirm if (0051,xx06,GEMS_FUNCTOOL_01) is still in use in current modalities ? Here is the DCS I am seeing ' GE MR System DICOM Conformance Statement (DOC3179154 Rev 3)' (*)

It states that attribute is: Store Parameters string delimited by character ESC=0x1B (27). However the VR is LT for this attribute. Since PS 3.5 specifies that:

...

Default Character Repertoire and/or as defined by (0008,0005) excluding Control Characters except TAB, LF, FF, CR (and ESC when used for [ISO/IEC 2022] escape sequences).

...

I fail to understand how to process the attribute in the case where Specific Character Set belong to one of those ISO 2022 character set family ?

Thanks for comments,

(*)

https://www.gehealthcare.com/-/jssmedia/documents/us-global/products/interoperability/dicom/magnetic-resonance-imaging-dicom-conformance-statements/2025/gehc-dicom-conformance_mr-system_doc3179154_rev3.pdf?rev=-1&hash=DA482608680F19225384B10E2B7D7095

[Jörg Riesmeier]

Hi Mathieu,

PS3.5 Section 6.1.3 specifies that "The ESC character shall be used only for [ISO/IEC 2022] character set control sequences, in accordance with Section 6.1.2.5." This means that the use of the ESC character (within text data) for any other purposes is not permitted according to the DICOM Standard. If a company has implemented this differently, it does not comply with the specification.

If I were you, I would simply ignore these non-standard private extensions (or reject the dataset, whichever seems more appropriate). I would also inform the manufacturer about the (potentially) non-compliant behavior of their product.

Regards,
Jörg


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Subject: [DICOM Forum] Store Parameters string delimited by character ESC=0x1B (27)
Date: Wednesday, April 15, 2026, 10:28:02 AM CEST
From: Mathieu Malaterre <mathieu....@gmail.com>
To: DICOM Forum <dicom...@googlegroups.com>

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Dr. Joerg Riesmeier, Etzhorner Weg 19, 26125 Oldenburg, Germany
E-Mail: di...@jriesmeier.com, Homepage: www.jriesmeier.com

[David Gobbi]

Hi Mathieu,

I have seen two distinct formats for (0051,xx06,GEMS_FUNCTOOL_01) in the wild. The older format uses decimal values delimited by ESC (0x1B), and explicit VR=LO. The newer format uses named parameters delimited by NL (0x0A), and explicit VR=LT. I don't know if there was a specific software version where the change occurred, but it was circa 2015.

The conformance statement that you linked is recent (2025), but I suspect the comment about the use of ESC as a delimiter is a copy-paste from an older conformance statement and is no longer accurate.

Regards,

David

[Mathieu Malaterre]

Hi David,

I learnt something new today thanks !

Just for later reference, I was unable to confirm your assertion about 'LO' using gemini, chatgpt & github search (I see LT in all cases). But I can confirm from the files I have access to, I see the numerical vs the key/value style. I will update the logic in my code to turn VR:LT into VR:UN only in the ESC+numerical case and keep LT for key/value case.

Thanks