Материал: part03

Enumerated Values:​

SINGLE​ successive single echo coverage​

PARTIAL​segmented coverage​

FULL​ single shot full coverage​

Required if Image Type (0008,0008) Value 1 is ORIGINAL or MIXED. May​ be present otherwise.​

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C.8.14.3 MR Spectroscopy Functional Group Macros​

The following sections contain Functional Group Macro's specific to the MR Spectroscopy IOD.​

Note​

The Attribute descriptions in the Functional Group Macros are written as if they were applicable to a single frame (i.e., the​ Macro is part of the Per-frame Functional Groups Sequence). If an Attribute is applicable to all frames (i.e., the Macro is part​ of the Shared Functional Groups Sequence) the phrase "this frame" in the Attribute description shall be interpreted to mean​ " for all frames".".​

C.8.14.3.1 MR Spectroscopy Frame Type Macro​

Table C.8-104 specifies the Attributes of the MR Spectroscopy Frame Type Functional Group Macro.​

Table C.8-104. MR Spectroscopy Frame Type Macro Attributes​

>Include Table C.8-107 “MR Spectroscopy Description Macro Attributes”​

C.8.14.3.2 MR Spectroscopy FOV/Geometry Macro​

Table C.8-105 specifies the Attributes of the MR Spectroscopy FOV/Geometry Functional Group Macro.​

Table C.8-105. MR Spectroscopy FOV/Geometry Macro Attributes​

Only a single Item shall be included in this Sequence.​

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Required if Frame Type (0008,9007) Value 1 of this frame is​

ORIGINAL. May be present otherwise.​

C.8.14.4 MR Spectroscopy Data Module​

Table C.8-106 specifies the Attributes that describe the Spectroscopy Data.​

Table C.8-106. MR Spectroscopy Data Module Attributes​

FREQUENCY​

TIME​

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C.8.14.4.1 Spectroscopy Data​

The Spectroscopy Data (5600,0020) Attribute contains the Signal intensities for the spectra. The order of voxels encoded for each​ spectral plane is left to right, top to bottom, i.e., the upper left voxel (labeled 1,1) is encoded first followed by the remainder of row 1,​ followed by the first voxel of row 2 (labeled 2,1) then the remainder of row 2 and so on. Each "voxel" represents an entire spectrum.​ The complete spectral data from each voxel is encoded, followed by the spectral data from the next voxel position.​

ThenumberofvoxelsoneachframearedescribedbyRows(0028,0010)andColumns(0028,0011).Thenumberofframesisdescribed​ byNumberofFrames(0028,0008).Theframesmayrepresentdifferentlocationsina3Dacquisition,orthesamepositionatadifferent​ point of time, or a difference of some other combination of Attributes.​

Note​

Either Rows or Columns or both may have a value of 1 (e.g., for single voxel spectroscopy). A value of zero for the corres-​ ponding value of Pixel Spacing in the Pixel Measures Macro is permitted under these circumstances. See Section 10.7.1.3.​

The spectral data points are ordered from high frequencies to low frequencies for a fixed static magnetic field strength, in the case​ that the Signal Domain Columns (0028,9003) or Signal Domain Rows (0028,9235) Attributes contain the value FREQUENCY.​

The spectral data points are ordered in sequence of increasing time in the case that the Signal Domain Columns (0028,9003) or​ Signal Domain Rows (0028,9235) Attributes contain the value TIME.​

The apparent rotation of magnetization in a quadrature representation shall be counterclockwise (from the (positive) real part to the​ (positive) imaginary part) for positive relative frequencies.​

Note​

WhenComplextimedatapointsaretransformedbyastraightforwardFouriertransformationtocomplexspectraldatapoints,​ these are ordered from low frequency to high frequency.​

Fortwo-dimensionalspectralacquisitions,theorderingissuchthatalldatapointsfromarow(correspondingtoalldatapointsacquired​ in an individual sampling period), are followed by all data points from the successive sampling period. Following all data of the rows​ fromagivenvoxelposition,thedatafromthesubsequentvoxelpositionareencoded.Theaxisparalleltotherowdirectioncorresponds​ to the sampling time axis. The axis parallel to the column direction corresponds to the evolution time axis.​

The dimensions of each spectrum that make up a voxel are described by Data Point Rows (0028,9001) and Data Point Columns​ (0028,9002). In the case of 1D spectra, the number of Data Point Rows shall be 1.​

For a Data Representation (0028,9108) value of COMPLEX, the order of data points is real channel followed by imaginary channel​ for each spectral data point. For the other Data Representation values (REAL, IMAGINARY and MAGNITUDE), each spectral data​ point contains only a single value.​

TheFigureC.8-18depicts6frameseachmadeupof4rowsand4columnsofvoxels.SpecificvaluesforDataPointRows(0028,9001)​ and Data Point Columns (0028,9002) of these voxels are not depicted.​

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Data

Point

Columns

Columns

Frames

Rows

Data

Point

Rows

Figure C.8-18. Dimensions of Spectroscopy Data​

C.8.14.5 MR Spectroscopy Description Macro​

Table C.8-107 specifies the Attributes that describe the Spectroscopy.​

Table C.8-107. MR Spectroscopy Description Macro Attributes​

C.8.14.5.1 MR Spectroscopy Description Attribute Description​

C.8.14.5.1.1 Image Type and Frame Type​

Image Type (0008,0008) and Frame Type (0008,9007) are not included in this Macro but one or the other is always included in the​ Module or Macro that invokes this Macro, and they are therefore described here.​

In addition to the requirements specified in Section C.8.16.1 Image Type and Frame Type, the following additional requirements and​ Defined Terms are specified.​

C.8.14.5.1.1.1 Pixel Data Characteristics​

See Section C.8.16.1.1. No additional requirements or Defined Terms.​

C.8.14.5.1.1.2 Patient Examination Characteristics​

See Section C.8.16.1.2. No additional requirements or Defined Terms.​

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