Материал: part03

C.7.6.17.1 Dimension Indices​

With the Dimension Index Sequence (0020,9222), Data Element Tags are specified that identify the indices used for a particular SOP​

Instance.​

The actual index values for each frame in a multi-frame header are stored in a single Dimension Index Values Attribute (0020,9157)​ defined in the Frame Content Functional Group. For each SOP Instance this Attribute has a Value Multiplicity equal to the number of​ Items in the Sequence. The ordering of the Items in the Sequence defines the ordering in the Dimension Index Values Attribute: Item​ 1 of the Sequence relates to Value 1, Item 2 to Value 2, etc.​

The Dimension Index Pointer (0020,9165) references a single Attribute that describes the actual values that define the dimension.​ Each Attribute referenced in the Dimension Index Sequence (0020,9222) will have an index stored in the Dimension Index Values​ (0020,9157) for each frame. Each index value is an ordinal number starting from 1 and monotonically increasing by 1 within the scope​ of a Dimension Organization UID (0020,9164). These values are independent of the actual values of the Attribute referenced by the​ Dimension Index Pointer (0020,9165), i.e., the index values are logical indices, rather than actual indices. Frames assigned the same​ index shall contain nominally the same value for the referenced Attribute. If the referenced Attribute is not present for some frames,​ or is present but has no value, then a single index shall be assigned to indicate the lack of the value (i.e., all such frames shall have​ thesameindexvalue,whichisdifferentfromotherindexvalues).ItisatthediscretionoftheSOPInstancecreatorwhethertheAttribute​ values are equivalent, and therefore appropriate for assignment to the same index value.​

The Dimension Index Pointer (0020,9165) shall contain the Data Element Tag (gggg,eeee) of the Attribute being indexed.​

The Dimension Index Pointer (0020,9165) shall not contain the Data Element Tag for Frame Content Sequence (0020,9111) or Di-​ mension Index Values (0020,9157).​

- Standard -​

Note​

1.​Dimension Index Pointer (0020,9165) may point to a Sequence containing a Functional Group. In that case all the At-​ tributes of the Sequence are associated with the index value.​

2.​TheDimensionIndexPointer(0020,9165)maypointtoaDataElementTag(gggg,eeee)thatisnotpresentforallframes​ of an object, or does not have a value for all frames of an object. For such frames, index values are still assigned, as​ described above.​

3.​TheindicesusedintheDimensionIndexValues(0020,9157)mayormaynotbeidenticaltothevalueofindexedAttribute​ referencedbyDimensionIndexPointer(0020,9165).Forexample,ifthereferencedAttributeisitselfencodedinanindex-​ like fashion (being an ordinal number starting from 1), such as In-Stack Position Number (0020,9057), then index value​ 1 would typically correspond to In-Stack Position Number (0020,9057) value 1. On the other hand, if the referenced​ Attributeencodessomephysicalmeasure,suchasatimeordistance,oracategoricalvalue,suchasastringdescribing​ the phase of contrast, or a more complex description such as an entire Functional Group, then the index value is inde-​ pendent of the encoded value.​

4.​ThescopeofthevaluesofDimensionIndexPointer(0020,9165)isdefinedtobewithinasingleDimensionOrganization​ UID (0020,9164). If the same Dimension Organization UID (0020,9164) is present in multiple Instances (whether part​ of a Concatenation or not), at least one of those Instances (though not necessarily every Instance) will contain a value​ of 1 for the Dimension Index Values (0020,9157).​

TheFunctionalGroupPointer(0020,9167)valueistheDataElementTag(gggg,eeee)oftheFunctionalGroupSequencethatcontains​ theAttributebeingindexed.IftheDimensionIndexPointer0020,9165)containsaDataElementTagthatidentifiesaFunctionalGroup​ Sequence then the Functional Group Pointer (0020,9167) shall not be present.​

If the Dimension Index Pointer (0020,9165) Attribute contains a Private Data Element, then the Dimension Index Private Creator​ (0020,9213) shall contain the Private Creator of the block of Private Data Elements.​

If the Functional Group Pointer (0020,9167) Attribute contains a Private Data Element, then the Functional Group Private Creator​ (0020,9238) shall contain the Private Creator of the block of Private Data Elements.​

Note​

AnexampleoftheusageoftheDimensionIndexSequence(0020,9222)andDimensionIndexValues(0020,9157)Attributes:​

Dimension Index Sequence (0020,9222) specifies two indices:​

•​Cardiac Trigger Delay Time (0020,9153)​

•​Image Position (Patient) (0020,0032)​

The Dimension Index Sequence (0020,9222) is filled with the following contents:​

The Dimension Index Values (0020,9157) (in the Frame Content Functional Group) for each frame consists of two values:​

Index of Cardiac Trigger Delay Time \ Index of Image Position​

The SOP Instance creator is responsible for maintaining consistency between the actual value of the Attribute listed as the​ Dimension Index Pointer (0020,9165) and the corresponding value in the Dimension Index Values (0020,9157) Attribute.​

See Figure C.7.6.17-1 for an illustration of this example.​

- Standard -​

Figure C.7.6.17-1. Example of Dimension Index Sequence and Dimension Index Values Attributes​

C.7.6.17.2 Dimension Organization UID​

The Dimension Organization UID (0020,9164) value identifies a set of dimensions to which an Item of the Dimension Index Sequence​ (0020,9222) belongs.​

When different SOP Instances share the same Dimension Organization UID (0020,9164) for a particular Item of the Dimension Index​ Sequence(0020,9222),equivalentindicesfromthecorrespondingDimensionIndexValues(0020,9157)shallhavethesamemeaning​ across the SOP Instances.​

This mechanism allows an image creator to explicitly specify that indices are intended to convey identical information across SOP​ Instances.​

Dimension Organization Sequence (0020,9221) contains a summary of all the Dimension Organization UID (0020,9164) values used​

in a SOP Instance.​

Note​

Figure C.7.6.17-2 illustrates how this is used for a SOP Instance created by a multi-planar reformat application from a SOP​ Instance containing three Items in the Dimension Index Sequence. The meaning of the indices for Temporal Position Index​ (0020,9128), and MR Echo Sequence (0018,9114) were preserved in the derived SOP Instance, so it shares the Dimension​

- Standard -​

Organization UID for these Attributes with the original. Since the reformat was performed with a different orientation, the​ meaning of the In-Stack Position Number (0020,9057) was not preserved. Therefore a new Dimension Organization UID​ (0020,9164) was created.​

Figure C.7.6.17-2. Example of Use of Dimension Organization Module​

C.7.6.17.3 Spatial Location and Optical Path of Tiled Images​

If Dimension Organization Type (0020,9311) is present with a value of TILED_FULL, then the Per-Frame Functional Group Macros​ thatwouldotherwisedescribethespatiallocationofeachtileexplicitly(e.g.,theX,YandZoffsetsfromtheoriginintheSlideCoordinate​ System Plane Position (Slide)), and the optical path, may be omitted.​

A value of TILED_FULL indicates that the frames across all Instances of a Concatentation, or a single Instance in the absence of a​ Concatenation, comprise a non-sparse non-overlapping representation of an entire rectangular region, and are sequentially encoded​ as successive frames in Pixel Data (7FE0,0010) in an implicit order varying:​

•​first along the row direction from left to right, where the row direction is defined in the Slide Coordinate System by the first three​ values of Image Orientation (Slide) (0048,0102),​

•​then along the column direction from top to bottom, where the column direction is defined in the Slide Coordinate System by the​ second three values of Image Orientation (Slide) (0048,0102),​

•​thenalongthedepthdirectionfromtheglassslidetowardsthecoverslip,wherethedepthdirectionisdefinedintheSlideCoordinate​ System from zero to positive,​

•​then along optical paths, where the direction is defined by successive Items of the Optical Path Sequence (0048,0105) in the order​ in which they are listed in that Sequence.​

If Dimension Organization Type (0020,9311) is absent or has a value of TILED_SPARSE, then the spatial location of each tile is ex-​ plicitly encoded using information in the Per-Frame Functional Group Sequence, and the recipient shall not make any assumption​ about the spatial position or optical path or order of the encoded frames but shall rely on the values of the relevant Per-Frame Func-​ tional Group Macro.​

C.7.6.18 Physiological Synchronization​

C.7.6.18.1 Cardiac Synchronization Module​

Table C.7.6.18-1 specifies the Attributes of the Cardiac Synchronization Module.​

- Standard -​

Required if Image Type (0008,0008) Value 1 is ORIGINAL or MIXED and Cardiac​

SynchronizationTechnique(0018,9037)equalsPROSPECTIVEorRETROSPECTIVE.​

OtherwisemaybepresentifImageType(0008,0008)Value1isDERIVEDandCardiac​

SynchronizationTechnique(0018,9037)equalsPROSPECTIVEorRETROSPECTIVE.​

- Standard -​