Terms and Definitions

Metadata - DICOM XML or DICOM JSON representation of DICOM dataset without the bulk data (large or binary data) replaced with Bulkdata URIs.

Value Representation (VR) of DS, FL, FD, IS, LT, OB, OD, OF, OL, OV, OW, SL, SS, ST, SV, UC, UL, UN, US, UT and UV are considered bulk data.
The user agent uses the Bulkdata URI to retrieve the Bulkdata.
Metadata does not include the Group 0002 File Meta Information Data Elements.

Bulk Data - An object that contains an octet-stream containing one or more Value Fields (typically containing large data, such as Pixel Data, PDF, CDA, waveform, video extracted from a DICOM Dataset).

There are two categories: uncompressed and compressed bulk data.

Bulk Data URI - A uniform resource identifier that references bulk data.

Resource - An abstract object with a type, associated data, relationship to other resources, and set of methods to operate on. The followings are examples of a resource:

/studies – All studies
/series – All series
/frames - A sequence of frames
/studies/{study}/series – Collection of series for a study
/studies/{study}/series/{series}/instances – Collection of instances of series
/studies/{study}/series/{series}/metadata
/studies/{study}/series/{series}/pixeldata
/studies/{study}/series/{series}/thumbnail
/studies/{study}/series/{series}/Bulkdata
/studies/{study}/series/{series}/instances/{instance}/frames - Contains a sequence of frames

Rendered Resource - DICOM dataset rendered to web consumable formats

PNG, JPEG, PDF, HTML, TXT, GIF, Video etc.
Option to burn overlay text annotation (Patient and procedure information burned into the image). Similar to the displayed (tag) in AngulaJS Medical Viewer.
Option to request View configuration - Window level, Scale, region, Frame, ICC color correction to be applied.
Presentation state to use (passing of Series and SOP Instance UIDs) to produce the view. This means the origin server will use the reference images in the softcopy presentation state to create the view (adding text and graphic annotation, w/l, overlay plane, shutter mask etc. to rendered view).
Rendered study or series are ambiguous unless there is a Structured Display or Softcopy Presentation State object in the study.
Rendered series or instance of Key Object Selection Document could also create a study view as it can reference Structured Display (layout), Softcopy Presentation State (view) object along with direct/indirect reference image instances (e.g. both the Structured Display and Presentation State object will have references to images and image frame to be displayed).
The ability to associate DICOM hanging protocol to a study helps with the rendered study creation.

Target URL - A URL is composed of three components.

For example, given the URI:

http://dicom.nema.org/service/studies/2.25.123456789/series/2.25.987654321

Base URI: "http://dicom.nema.org/service"
Origin Server Service Root Path: "/service"
Target Resource: "/studies/2.25.123456789/series/2.25.987654321"–––––
Query Parameters: "?" parameter *("&" parameter)
- keyword = %s DQUOTE 1*ALPHA *(ALPHA / DIGIT) DQUOTE
- tag = 8HEXDIG
- Note: case sensitive name from DICOM Tag Table or TAG in HEX representation.
- Multiple key values are coma separate.
Note: A sequence-attribute is two or more attributes separated by the dot character ".", all but the last attribute shall have a VR of SQ.

Representation - A resource is an abstract concept that is made concrete by a representation, which is a data object encoded in an octet-stream.

Media Type - A media type defines the format and algorithms needed for encoding and decoding resources into representations.

Also it specifies whether the payload contains a single or multiple representations (single part /multipart).

Media type is used in Content-Type and Accept header fields (data typing and type negotiation).

If a Transfer Syntax parameter for a DICOM Media Type is not specified in a request or response, the Transfer Syntax in the response shall be the Transfer Syntax specified as the default for the Resource Category and media type combination (lossy, video, and uncompressed is always in Explicit VR Little Endian representation).

Character Set - The character encoding of textual content in representations.

"UTF-8" charset name for RESTful Retrieve Rendered transaction.
DICOM Defined Terms for the character set.
IANA character sets.
Acceptable Character Sets header field - acceptable to the user agent in the response.

Transaction - A Transaction is composed of a request/response message pair.

Method - An HTTP method, such as CONNECT, DELETE, GET, HEAD, OPTIONS, POST, PUT.

Search Query Parameters:

search= {Match} / {Fuzzy Matching} / {Includefield} / {Limit} / {Offset}

Match - Types of matching allowed by C-FIND and results generated according to the Hierarchical Search Method (e.g., study->series->instance)
Fuzzy Matching - Optional person names matching using Section C.2.2.2.1.1 in PS3.4.
Includefield - List of attributes that should be included in the response similar to DIMSE Return Keys. "all" means return all available attributes (available to origin server) for the object.
Limit - Maximum number of results returned.
Offset - Number of skipped results. The combination of Limit and Offset allows for query results pagination.

Example of query studies from a certain day and limit the number of results, start with offset 0:

GET /radiology/studies?00080020=20230817&limit=20&offset=0&includefield=all HTTP/1.1 
Host: www.hospital-stmarco 
Accept: application/dicom+json

Terms and Definitions

See Also