DICOM PS3.18 2019a - Web Services

8.2.11 Transfer Syntax UID

For the URI mode the parameter name shall be "transferSyntax" containing one value.

The Transfer Syntax to be used within the DICOM image objects, as specified in PS3.6. This parameter is OPTIONAL for the URI mode. It shall not be present if contentType is other than application/dicom.

By default the DICOM object(s) returned shall be encoded in Explicit VR Little Endian. Neither Implicit VR, nor Big Endian shall be used. The response shall be the Transfer Syntax requested if possible. If it is not possible for the response to be sent using the requested transfer syntax then the Explicit VR Little Endian Uncompressed Transfer Syntax shall be used, unless the pixel data in its compressed form is of such length that it cannot be encoded in the Explicit VR Little Endian Uncompressed Transfer Syntax.


  1. If transcoding to the Explicit VR Little Endian Transfer Syntax, a VR of UN may be needed for the encoding of Data Elements with explicit VR whose value length exceeds 65534 (216-2) (FFFEH, the largest even length unsigned 16 bit number) but which are defined to have a 16 bit explicit VR length field. See Section 6.2.2 in PS3.5 .

  2. The transfer syntax can be one of the JPIP Transfer Syntaxes, in which case the returned objects will contain the URL of the JPIP provider for retrieving the pixel data.

The value(s) shall be encoded as a unique identifier (UID) string, as specified in PS3.5, except that it shall not be padded to an even length with a NULL character.

DICOM PS3.18 2019a - Web Services