DICOM PS3.18 2021e - Web Services
8.7.3.5.2 Transfer Syntax Parameter

For a given DICOM Media Type, a single Transfer Syntax parameter value may be specified, but its usage may be constrained by the service for which they are used.

RESTful origin servers shall support the Transfer Syntax parameter.

Transfer syntax media type parameters are forbidden in URI Service requests and responses.

The syntax is:

transfer-syntax-mtp = OWS ";" OWS %s"transfer-syntax=" ts-value
ts-value            = transfer-syntax-uid / "*"
transfer-syntax-uid ; a UID from Table A-1 “UID Values” in PS3.6 with a UID Type of Transfer Syntax

The value of the Transfer Syntax parameter may be either a Transfer Syntax UID or the token "*".

For example, to specify that 1.2.840.10008.1.2.4.50 is the acceptable Transfer Syntaxes, an Accept header field could be:

Accept: application/dicom; transfer-syntax=1.2.840.10008.1.2.4.50

A DICOM Media Type may only have one Transfer Syntax parameter and it shall have only one value.

Note

Per [RFC6838] Media Type Specifications and Registration Procedures, it is an error for a specific parameter to be specified more than once. If a choice of Transfer Syntaxes is acceptable. more than one media type may be provided in the Accept header with different q parameter values to indicate preference. E.g., to specify that 1.2.840.10008.1.2.4.50 and to specify that 1.2.840.10008.1.2.4.57 are acceptable but 1.2.840.10008.1.2.4.50 is preferred, an Accept header field could be:

Accept: multipart/related; type="application/dicom";transfer-syntax=1.2.840.10008.1.2.4.50;boundary=**, multipart/related; type="application/dicom";transfer-syntax=1.2.840.10008.1.2.4.57;q=0.5;boundary=**

The wildcard value "*" indicates that the user agent will accept any Transfer Syntax. This allows, for example, the origin server to respond without needing to transcode an existing representation to a new Transfer Syntax, or to respond with the Explicit VR Little Endian Transfer Syntax regardless of the Transfer Syntax stored, unless the origin server has only access to the pixel data in lossy compressed form or the pixel data in a lossless compressed form that is of such length that it cannot be encoded in the Explicit VR Little Endian Transfer Syntax.

If an Origin server supports the Transfer Syntax parameter, it shall support the wildcard value.

Origin servers that support the Transfer Syntax parameter shall specify in their Conformance Statement those values of Transfer Syntax parameter that are supported in the response.

User agents that support the Transfer Syntax parameter shall specify in their Conformance Statement those Transfer Syntax parameter values that may be supplied in the request.

DICOM PS3.18 2021e - Web Services