D.4.2.4.3 Association Initiation Policy
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##### D.4.2.4.3 Association Initiation Policy

FIND-SCU attempts to initiate a new association when the user performs the query action from the user interface. If this involves recursive queries for lower query levels in the hierarchy, these will be performed on the same association.

###### D.4.2.4.3.1 Activity - Query Remote AE

###### D.4.2.4.3.1.1 Description and Sequencing of Activities

A single attempt will be made to query the remote AE. If the query fails, for whatever reason, no retry will be performed.

###### D.4.2.4.3.1.2 Proposed Presentation Contexts

Table D.4.2-22. Proposed Presentation Contexts for FIND-SCU and Query Remote AE

Presentation Context Table
Abstract Syntax | Transfer Syntax | Role | Extended Negotiation
--- | --- | --- | ---
Name | UID | Name | UID
See Table D.4.2-18 | See Table D.4.2-18 | Implicit VR Little Endian | 1.2.840.10008.1.2 | SCU | None
Explicit VR Little Endian | 1.2.840.10008.1.2.1
Explicit VR Big Endian | 1.2.840.10008.1.2.2

FIND-SCU will propose multiple Presentation Contexts, one for each of the supported Transfer Syntaxes, and an additional Presentation Context with all of the supported Transfer Syntaxes, in order to determine which Transfer Syntaxes the remote SCP supports, and which it prefers.

###### D.4.2.4.3.1.2.1 Extended Negotiation

No extended negotiation is performed.

In particular, relational queries are not supported.

###### D.4.2.4.3.1.3 SOP Specific Conformance

###### D.4.2.4.3.1.3.1 SOP Specific Conformance to C-FIND SOP Classes

FIND-SCU provides standard conformance to the supported C-FIND SOP Classes.

Only a single information model, Study Root, is supported.

All queries are initiated at the highest level of the information model (the STUDY level), and then for each response received, recursively repeated at the next lower levels (the SERIES and then IMAGE levels), in order to completely elucidate the "tree" of instances available on the remote AE (from which the user may subsequently request a retrieval at any level).

No CANCEL requests are ever issued.

Unexpected attributes returned in a C-FIND response (those not requested) are listed in the browser at the appropriate level if present in the dictionary. Requested return attributes not returned by the SCP are ignored. Non-matching responses returned by the SCP due to unsupported (hopefully optional) matching keys are not filtered locally by the FIND-SCU and thus will still be presented in the browser. No attempt is made to filter out duplicate responses.

Specific Character Set will always be included at every query level. If present in the response, Specific Character Set will be used to identify character sets other than the default character set for display of strings in the browser.

Table D.4.2-23. Study Root Request Identifier for FIND-SCU

Name | Tag | Types of Matching
--- | --- | ---
STUDY Level |  |
Patient's ID | (0010,0020) | S,*,U
Patient's Name | (0010,0010) | S,*,U
Patient's Birth Date | (0010,0030) | S,*,U,R
Patient's Sex | (0010,0040) | S,*,U
Patient's Birth Time | (0010,0032) | S,*,U,R
Other Patient's ID's | (0010,1000) | S,*,U
Other Patient's Names | (0010,1001) | S,*,U
Ethnic Group | (0010,2160) | S,*,U
Patient Comments | (0010,4000) | S,*,U
Study ID | (0020,0010) | S,*,U
Study Description | (0008,1030) | S,*,U
Modalities In Study | (0008,0061) | S,*,U
Study Date | (0008,0020) | S,*,U,R
Study Time | (0008,0030) | S,*,U,R
Referring Physician's Name | (0008,0090) | S,*,U
Accession Number | (0008,0050) | S,*,U
Physician of Record | (0008,1048) | S,*,U
Name of Physician(s) Reading Study | (0008,1060) | S,*,U
Admitting Diagnoses Description | (0008,1080) | S,*,U
Patient's Age | (0010,1010) | S,*,U
Patient's Size | (0010,1020) | S,*,U
Patient's Weight | (0010,1030) | S,*,U
Occupation | (0010,2180) | S,*,U
Additional Patient History | (0010,21B0) | S,*,U
Study Instance UID | (0020,000D) | UNIQUE
SERIES Level |  |
Series Number | (0020,0011) | S,*,U
Series Description | (0008,103E) | S,*,U
Modality | (0008,0060) | S,*,U
Series Date | (0008,0021) | S,*,U
Series Time | (0008,0031) | S,*,U
Performing Physician's Name | (0008,1050) | S,*,U
Protocol Name | (0018,1030) | S,*,U
Operator's Name | (0008,1070) | S,*,U
Laterality | (0020,0060) | S,*,U
Body Part Examined | (0018,0015) | S,*,U
Manufacturer | (0008,0070) | S,*,U
Manufacturer's Model Name | (0008,1090) | S,*,U
Station Name | (0008,1010) | S,*,U
Institution Name | (0008,0080) | S,*,U
Institutional Department Name | (0008,1040) | S,*,U
Series Instance UID | (0020,000E) | UNIQUE
IMAGE Level |  |
Instance Number | (0020,0013) | S,*,U
Image Comments | (0020,4000) | S,*,U
Content Date | (0008,0023) | S,*,U,R
Content Time | (0008,0033) | S,*,U,R
Image Type | (0008,0008) | S,*,U
Acquisition Number | (0020,0012) | S,*,U
Acquisition Date | (0008,0022) | S,*,U,R
Acquisition Time | (0008,0032) | S,*,U,R
Acquisition Date Time | (0008,002A) | S,*,U,R
Derivation Description | (0008,2111) | S,*,U
Contrast/Bolus Agent | (0018,0010) | S,*,U
Quality Control Image | (0028,0300) | S,*,U
Burned In Annotation | (0028,0301) | S,*,U
Lossy Image Compression | (0028,2110) | S,*,U
Lossy Image Compression Ratio | (0028,2112) | S,*,U
Number of Frames | (0028,0008) | S,*,U
SOP Instance UID | (0008,0018) | UNIQUE
SOP Class UID | (0008,0016) | NONE
Common to all query levels |  |
Specific Character Set | (0008,0005) | S,*,U

Types of Matching:

The types of Matching supported by the C-FIND SCU. An "S" indicates the identifier attribute uses Single Value Matching, an "R" indicates Range Matching, a n"*"indicates wild card matching, a 'U' indicates Universal Matching, and an 'L' indicates that UID lists are sent. "NONE" indicates that no matching is supported, but that values for this Element are requested to be returned (i.e., universal matching), and "UNIQUE" indicates that this is the Unique Key for that query level, in which case Universal Matching or Single Value Matching is used depending on the query level.

###### D.4.2.4.3.1.3.2 Presentation Context Acceptance Criterion

FIND-SCU does not accept associations.

###### D.4.2.4.3.1.3.3 Transfer Syntax Selection Policies

FIND-SCU prefers explicit Transfer Syntaxes. If offered a choice of Transfer Syntaxes in the accepted Presentation Contexts, it will apply the following priority to the choice of Presentation Context to use for the C-STORE operation:

1. first encountered explicit Transfer Syntax,

2. default Transfer Syntax.

###### D.4.2.4.3.1.3.4 Response Status

FIND-SCU will behave as described in Table D.4.2-24 in response to the status returned in the C-FIND response command message(s).

Table D.4.2-24. Response Status for FIND-SCU and Query Remote AE Request

Service Status | Further Meaning | Status Codes | Behavior
--- | --- | --- | ---
Refused | Out of Resources | A700 | Current query is terminated; remaining queries continue
Error | Identifier does not match SOP Class | A900 | Current query is terminated; remaining queries continue
| Unable to process | Cxxx | Current query is terminated; remaining queries continue
Cancel | Matching terminated due to Cancel request | FE00 | Ignored (should never occur, since cancels never issued)
Success | Matching is complete - No final Identifier is supplied | 0000 | Current query is terminated; remaining queries continue
Pending | Matches are continuing - Current Match is supplied and any Optional Keys were supported in the same manner as Required Keys | FF00 | Identifier used to populate browser and trigger recursive lower level queries
| Matches are continuing - Warning that one or more Optional Keys were not supported for existence and/or matching for this Identifier | FF01 | Identifier used to populate browser and trigger recursive lower level queries

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