C.8.13.5 Enhanced MR Image Functional Group Macros

The following sections contain Functional Group macros specific to the Enhanced MR Image 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.8.13.5.1 MR Image Frame Type Macro

Table C.8-88 specifies the attributes of the MR Image Frame Type Functional Group macro.

Table C.8-88MR IMAGE FRAME TYPE MACRO ATTRIBUTES

Attribute Name Tag Type Attribute Description
MR Image Frame Type Sequence (0018,9226) 1 Identifies the characteristics of this frame. Only a single Item shall be included in this sequence.
>Frame Type (0008,9007) 1 Type of Frame. A multi-valued attribute analogous to the Image Type (0008,0008). Enumerated Values and Defined Terms are the same as those for the four values of the Image Type (0008,0008) attribute, except that the value MIXED is not allowed. See C.8.16.1 and C.8.13.1.1.1.
>Include Common CT/MR Image Description Macro' Table C.8-131
>Include 'MR Image Description Macro' Table C.8-82

C.8.13.5.2 MR Timing and Related Parameters Macro

Table C.8-89 specifies the attributes of the MR Timing and Related Parameters Functional Group macro.

Table C.8-89MR TIMING AND RELATED PARAMETERS MACRO ATTRIBUTES

Attribute Name Tag Type Attribute Description
MR Timing and Related Parameters Sequence (0018,9112) 1 Identifies the timing and safety information of this frame. Only a single Item shall be included in this sequence.
>Repetition Time (0018,0080) 1C The time in ms between two successive excitations of the same volume. Shall be 0 (zero) if there is a single excitation per volume. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Flip Angle (0018,1314) 1C Steady state angle in degrees to which the magnetic vector is flipped from the magnetic vector of the primary field. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Echo Train Length (0018,0091) 1C Number of lines in k-space acquired per excitation of the same volume regardless of the type of echo or the number of frames derived from them. See section C.8.12.5.2.1. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>RF Echo Train Length (0018,9240) 1C Number of RF echoes collected per RF shot (or excitation) per frame. A value of zero shall correspond to a pure gradient echo frame. Note that this value corresponds to the current frame. Several frames may be derived from the same shot. See section C.8.13.5.2.1. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Gradient Echo Train Length (0018,9241) 1C Number of gradient echoes collected per RF echo per shot (or excitation) per frame. A value of zero shall correspond to a pure RF echo frame. If RF Echo Train Length (0018,9240) is non zero and Gradient Echo Train Length is as well then only the central echo will be an RF Spin Echo, all others will be gradient echoes. See section C.8.13.5.2.1. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Specific Absorption Rate Sequence (0018,9239) 1C Sequence containing the methods of SAR calculation and the corresponding values. One or more Items shall be included in this sequence. Required if the system is capable of calculating Specific Absorption Rate (0018,9181).
>>Specific Absorption Rate Definition (0018,9179) 1 Specification of the method of SAR calculation as defined in Applicable Safety Standard Description (0018,9174). Defined Terms: IEC_WHOLE_BODY IEC_PARTIAL_BODY IEC_HEAD IEC_LOCAL
>>Specific Absorption Rate Value (0018,9181) 1 Specific Absorption Rate in W/kg.
>Gradient Output Type (0018,9180) 1C Definition of gradient output unit, for which the value is stored in Gradient Output (0018,9182). Defined Terms: DB_DT = in T/s ELECTRIC_FIELD = in V/m PER_NERVE_STIM = percentage of peripheral nerve stimulation Required if the system is capable of calculating Gradient Output (0018,9182).
>Gradient Output (0018,9182) 1C Unit is defined by Gradient Output Type (0018,9180). Required if the system is capable of calculating Gradient Output (0018,9182).
>Operating Mode Sequence (0018,9176) 1C Sequence of operating mode information relating to the frame/SOP instance as required to adhere to the Applicable Safety Standard Agency (0018,9174) regulations. One or more Items shall be included in this sequence. Required if required by law or regulations. May be present otherwise.
>>Operating Mode Type (0018,9177) 1 Defined Terms: STATIC FIELD RF GRADIENT
>>Operating Mode (0018,9178) 1 Operating mode applicable for the defined by the applicable standard. Defined Terms: IEC_NORMAL IEC_FIRST_LEVEL IEC_SECOND_LEVEL

C.8.13.5.2.1 RF Echo Train Length and Gradient Echo Train Length Attributes Usage

The three Echo Train Length attributes all specify information related to the pulse sequence, one or more frames, and the echo type. The following examples illustrate their usage.

For a sequence with each excitation/shot producing 2 spin echoes that produce a line of k-Space for 2 different frames, the following values would be used for each frame:

Echo Train Length 2
Gradient Echo Train Length 0
RF Echo Train Length 1

For a sequence with each excitation/shot producing 2 gradient echoes that produce a line of k-Space for 2 different frames, the following values would be used:

Echo Train Length 2
Gradient Echo Train Length 1
RF Echo Train Length 0

For a sequence with each excitation/shot producing 8 spin echoes that produce 8 lines of k-Space for 1 frame, the following values would be used:

Echo Train Length 8
Gradient Echo Train Length 0
RF Echo Train Length 8

C.8.13.5.3 MR FOV/Geometry Macro

Table C.8-90 specifies the attributes of the MR FOV/Geometry Functional Group macro.

Table C.8-90MR FOV/GEOMETRY MACRO ATTRIBUTES

Attribute Name Tag Type Attribute Description
MR FOV/Geometry Sequence (0018,9125) 1 Identifies the geometry parameters of this frame. Only a single Item shall be included in this sequence.
>In-plane Phase Encoding Direction (0018,1312) 1C The axes of the in-plane phase encoding with respect to the frame. Enumerated Values: COLUMN ROW OTHER Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>MR Acquisition Frequency Encoding Steps (0018,9058) 1C Number of Frequency Encoding steps (kx) acquired Required if Frame Type (0008,9007) Value 1 is ORIGINAL. May be present otherwise.
>MR Acquisition Phase Encoding Steps in-plane (0018,9231) 1C Number of In-Plane Phase Encoding steps (ky) acquired Required if Frame Type (0008,9007) Value 1 is ORIGINAL. May be present otherwise.
>MR Acquisition Phase Encoding Steps out-of-plane (0018,9232) 1C Number of Out-of-Plane Phase Encoding steps (kz) acquired Required if MR Acquisition Type (0018,0023) equals 3D and Frame Type (0008,9007) Value 1 is ORIGINAL. May be present otherwise.
>Percent Sampling (0018,0093) 1C Fraction of acquisition matrix lines acquired, expressed as a percent. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Percent Phase Field of View (0018,0094) 1C Ratio of field of view dimension in phase direction to field of view dimension in frequency direction, expressed as a percent. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.

C.8.13.5.4 MR Echo Macro

Table C.8-91 specifies the attributes of the MR Echo Functional Group macro.

Table C.8-91MR ECHO MACRO ATTRIBUTES

Attribute Name Tag Type Attribute Description
MR Echo Sequence (0018,9114) 1 Identifies echo timing of this frame. Only a single Item shall be included in this sequence.
>Effective Echo Time (0018,9082) 1C The time in ms between the middle of the excitation pulse and the peak of the echo produced for kx=0. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.

C.8.13.5.5 MR Modifier Macro

Table C.8-92 specifies the attributes of the MR Modifier Functional Group macro.

Table C.8-92MR MODIFIER MACRO ATTRIBUTES

Attribute Name Tag Type Attribute Description
MR Modifier Sequence (0018,9115) 1 Identifies general acquisition parameters of this frame. Only a single Item shall be included in this sequence.
>Inversion Recovery (0018,9009) 1C Inversion Recovery preparatory sequence. Enumerated Values: YES NO Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Inversion Times (0018,9079) 1C Times in ms after the middle of inverting RF pulse to middle of excitation pulse to detect the amount of longitudinal magnetization. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL and Inversion Recovery (0018,9009) equals YES. Otherwise may be present if Frame Type (0008,9007) Value 1 is DERIVED and Inversion Recovery (0018,9009) equals YES.
>Flow Compensation (0018,9010) 1C Flow Compensation. Defined Terms: ACCELERATION VELOCITY OTHER NONE Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Flow Compensation Direction (0018,9183) 1C Flow Compensation Direction. Enumerated Values: PHASE FREQUENCY SLICE_SELECT SLICE_AND_FREQ SLICE_FREQ_PHASE PHASE_AND_FREQ SLICE_AND_PHASE OTHER Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL and Flow Compensation (0018,9010) equals other than NONE. Otherwise may be present if Frame Type (0008,9007) Value 1 is DERIVED and Flow Compensation (0018,9010) equals other than NONE.
>Spoiling (0018,9016) 1C Spoiling. Enumerated Values: RF = RF spoiled GRADIENT = gradient spoiled RF_AND_GRADIENT NONE Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL and Echo Pulse Sequence (0018,9008) equals GRADIENT or BOTH. Otherwise may be present if Frame Type (0008,9007) Value 1 is DERIVED and Echo Pulse Sequence (0018,9008) equals GRADIENT or BOTH.
>T2 Preparation (0018,9021) 1C T2 prepared Pulse Sequence. Enumerated Values: YES NO Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Spectrally Selected Excitation (0018,9026) 1C Spectrally Selected Excitation. Enumerated Values: WATER = water excitation FAT = fat excitation NONE Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Spatial Pre-saturation (0018,9027) 1C Spatial Pre-saturation. Defined Terms: SLAB NONE Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Partial Fourier (0018,9081) 1C Partial Fourier. Enumerated Values: YES NO Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Partial Fourier Direction (0018,9036) 1C Direction of Partial Fourier. Enumerated Values: PHASE FREQUENCY SLICE_SELECT COMBINATION Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL and Partial Fourier (0018,9081) equals YES. Otherwise may be present if Frame Type (0008,9007) Value 1 is DERIVED and Partial Fourier (0018,9081) equals YES.
>Parallel Acquisition (0018,9077) 1C Parallel acquisition has been used to reduce measurement time. Enumerated Values: YES NO Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Parallel Acquisition Technique (0018,9078) 1C Parallel acquisition characteristics. Defined Terms: PILS SENSE SMASH OTHER Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL and Parallel Acquisition (0018,9077) equals YES. Otherwise may be present if Frame Type (0008,9007) Value 1 is DERIVED and Parallel Acquisition (0018,9077) equals YES.
>Parallel Reduction Factor In-plane (0018,9069) 1C Measurement time reduction factor expressed as ratio of original and reduced measurement time for the in-plane direction. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL and Parallel Acquisition (0018,9077) equals YES. Otherwise may be present if Frame Type (0008,9007) Value 1 is DERIVED and Parallel Acquisition (0018,9077) equals YES.
>Parallel Reduction Factor out-of-plane (0018,9155) 1C Measurement time reduction factor expressed as ratio of original and reduced measurement time for the out-of-plane direction Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL and Parallel Acquisition (0018,9077) equals YES. Otherwise may be present if Frame Type (0008,9007) Value 1 is DERIVED and Parallel Acquisition (0018,9077) equals YES.
>Parallel Reduction Factor Second In-plane (0018,9168) 1C Measurement time reduction factor expressed as ratio of original and reduced measurement time for the second in-plane direction. Only required for MR Spectroscopy SOP Instances. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL and Parallel Acquisition (0018,9077) equals YES. Otherwise may be present if Frame Type (0008,9007) Value 1 is DERIVED and Parallel Acquisition (0018,9077) equals YES.

C.8.13.5.6 MR Imaging Modifier Macro

Table C.8-93 specifies the attributes of the MR Imaging Modifier Functional Group macro.

Table C.8-93MR IMAGING MODIFIER MACRO ATTRIBUTES

Attribute Name Tag Type Attribute Description
MR Imaging Modifier Sequence (0018,9006) 1 Identifies sequence containing MR modifier Sequence Attributes. Only a single item shall be included in this sequence.
>Magnetization Transfer (0018,9020) 1C Magnetization Transfer pulse sequence. Enumerated Values: ON_RESONANCE OFF_RESONANCE NONE Required if Frame Type (0008,9007) Value 1 is ORIGINAL. May be present otherwise.
>Blood Signal Nulling (0018,9022) 1C Blood Signal Nulling (“Black Blood”) preparatory pulse sequence. Enumerated Values: YES NO Required if Frame Type (0008,9007) Value 1 is ORIGINAL. May be present otherwise.
>Tagging (0018,9028) 1C Tagging. Defined Terms: GRID LINE NONE Required if Frame Type (0008,9007) Value 1 is ORIGINAL. May be present otherwise.
>Tag Spacing First Dimension (0018,9030) 1C Space between lines in mm. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL and Tagging (0018,9028) is GRID or LINE. Otherwise may be present if Frame Type (0008,9007) Value 1 is DERIVED and Tagging (0018,9028) is GRID or LINE.
>Tag Spacing Second Dimension (0018,9218) 1C Space between the lines in mm in the other direction. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL and Tagging (0018,9028) is GRID. Otherwise may be present if Frame Type (0008,9007) Value 1 is DERIVED and Tagging (0018,9028) is GRID.
>Tag Angle First Axis (0018,9019) 1C Angle of the tag lines relative to the rows axis (left to right) of the image, with a range of 0-180 degrees. The angle is increasing in clockwise direction. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL and Tagging (0018,9028) is GRID or LINE. Otherwise may be present if Frame Type (0008,9007) Value 1 is DERIVED and Tagging (0018,9028) is GRID or LINE.
>Tag Angle Second Axis (0018,9219) 1C Angle of the tag lines relative to the rows axis (left to right) of the image, with a range of 0-180 degrees. The angle is increasing in clockwise direction. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL and Tagging (0018,9028) is GRID. Otherwise may be present if Frame Type (0008,9007) Value 1 is DERIVED and Tagging (0018,9028) is GRID.
>Tag Thickness (0018,9035) 1C Thickness of the line in mm. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL and Tagging (0018,9028) is GRID or LINE. Otherwise may be present if Frame Type (0008,9007) Value 1 is DERIVED and Tagging (0018,9028) is GRID or LINE.
>Tagging Delay (0018,9184) 3 Delay time in ms of the beginning of the application of the tagging pattern relative to the last R-peak.
>Transmitter Frequency (0018,9098) 1C Center transmitter frequency in MHz. Required if Frame Type (0008,9007) Value 1 is ORIGINAL. May be present otherwise.
>Pixel Bandwidth (0018,0095) 1C Reciprocal of the effective sampling period, in hertz per pixel. Required if Frame Type (0008,9007) Value 1 is ORIGINAL. May be present otherwise.

C.8.13.5.7 MR Receive Coil Macro

Table C.8-94 specifies the attributes of the MR Receive Coil Functional Group macro.

Table C.8-94MR RECEIVE COIL MACRO ATTRIBUTES

Attribute Name Tag Type Attribute Description
MR Receive Coil Sequence (0018,9042) 1 A sequence that provides information about each receive coil used. Only a single Item shall be included in this sequence.
>Receive Coil Name (0018,1250) 1C Name of receive coil used. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Receive Coil Manufacturer Name (0018,9041) 2C Name of manufacturer of receive coil. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Receive Coil Type (0018,9043) 1C Type of receive coil used. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise. Defined Terms: BODY VOLUME = head, extremity, etc. SURFACE MULTICOIL
>Quadrature Receive Coil (0018,9044) 1C Indicates whether the receive coil is quadrature. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise. Enumerated Values: YES = quadrature or circularly polarized NO = linear
>Multi-Coil Definition Sequence (0018,9045) 1C A sequence that provides information regarding each element of a multi-coil. It should include attributes for all elements, whether used in the current acquisition or not. One or more Items shall be included in this sequence. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL and Receive Coil Type (0018,9043) equals MULTICOIL. May be present otherwise only if Receive Coil Type (0018,9043) equals MULTICOIL.
>>Multi-Coil Element Name (0018,9047) 1 Name of element of multi-coil.
>>Multi-Coil Element Used (0018,9048) 1 Indicates whether the multi-coil element was used in the current acquisition. Enumerated Values: YES NO
>Multi-Coil Configuration (0018,9046) 3 A textual description of the configuration of multi-coil elements which was used in the current acquisition.

C.8.13.5.8 MR Transmit Coil Macro

Table C.8-95 specifies the attributes of the MR Transmit Coil Functional Group macro.

Table C.8-95MR TRANSMIT COIL MACRO ATTRIBUTES

Attribute Name Tag Type Attribute Description
MR Transmit Coil Sequence (0018,9049) 1 A sequence that provides information about the transmit coil used. Only a single Item shall be included in this sequence.
>Transmit Coil Name (0018,1251) 1C Name of transmit coil used. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Transmit Coil Manufacturer Name (0018,9050) 2C Name of manufacturer of transmit coil. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Transmit Coil Type (0018,9051) 1C Type of transmit coil used. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise. Defined Terms: BODY VOLUME = head, extremity, etc. SURFACE

C.8.13.5.9 MR Diffusion Macro

Table C.8-96 specifies the attributes of the MR Diffusion Functional Group macro.

Table C.8-96MR DIFFUSION MACRO ATTRIBUTES

Attribute Name Tag Type Attribute Description
MR Diffusion Sequence (0018,9117) 1 Identifies the diffusion parameters of this frame. Only a single Item shall be included in this sequence.
>Diffusion b-value (0018,9087) 1C Diffusion sensitization factor in sec/mm2. This is the actual b-value for original frames and those derived from frames with the same b-value, or the most representative b-value when derived from images with different b-values. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Diffusion Directionality (0018,9075) 1C Specifies whether diffusion conditions for the frame are directional, or isotropic with respect to direction. Defined Terms: DIRECTIONAL BMATRIX ISOTROPIC NONE = to be used when Frame Type (0008,9007) value 4 equals DIFFUSION_ANISO or Diffusion b-value (0018,9087) is 0 (zero). Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Diffusion Gradient Direction Sequence (0018,9076) 1C Sequence containing orientations of all diffusion sensitization gradients that were applied during the acquisition of this frame. Only a single Item shall be included in this sequence. Required if Diffusion Directionality (0018,9075) equals DIRECTIONAL May be present if Diffusion Directionality (0018,9075) equals BMATRIX.
>>Diffusion Gradient Orientation (0018,9089) 1C The direction cosines of the diffusion gradient vector with respect to the patient Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Diffusion b-matrix Sequence (0018,9601) 1C The directional diffusion sensitization expressed as a 3x3 matrix with diagonal symmetry (with six unique elements from which the other elements can be derived). The rows and columns of the matrix are the X (right to left), Y (anterior to posterior) and Z (foot to head) patient-relative orthogonal axes as defined in C.7.6.2.1.1. The values are in units of ms/mm2. Only a single Item shall be included in this sequence. Required if Diffusion Directionality (0018,9075) equals BMATRIX.
>>Diffusion b-value XX (0018,9602) 1 The value of b[X,X].
>>Diffusion b-value XY (0018,9603) 1 The value of b[X,Y].
>>Diffusion b-value XZ (0018,9604) 1 The value of b[X,Z].
>>Diffusion b-value YY (0018,9605) 1 The value of b[Y,Y].
>>Diffusion b-value YZ (0018,9606) 1 The value of b[Y,Z].
>>Diffusion b-value ZZ (0018,9607) 1 The value of b[Z,Z].
>Diffusion Anisotropy Type (0018,9147) 1C Class of diffusion anisotropy calculation. Defined Terms: FRACTIONAL RELATIVE VOLUME_RATIO Required if Frame Type (0008,9007) value 4 equals DIFFUSION_ANISO.

C.8.13.5.10 MR Averages Macro

Table C.8-97 specifies the attributes of the MR Averages Functional Group macro.

Table C.8-97MR AVERAGES MACRO ATTRIBUTES

Attribute Name Tag Type Attribute Description
MR Averages Sequence (0018,9119) 1 Identifies the averaging parameters of this frame. Only a single Item shall be included in this sequence.
>Number of Averages (0018,0083) 1C Maximum number of times any point in k-space is acquired. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.

C.8.13.5.11 MR Spatial Saturation Macro

Table C.8-98 specifies the attributes of the MR Spatial Saturation Functional Group macro.

Table C.8-98MR SPATIAL SATURATION MACRO ATTRIBUTES

Attribute Name Tag Type Attribute Description
MR Spatial Saturation Sequence (0018,9107) 2 A sequence that provides the position of spatial saturation bands deposited as part of the pulse sequence. Zero or more Items shall be included in this sequence.
>Slab Thickness (0018,9104) 1 Thickness of slab in mm.
>Slab Orientation (0018,9105) 1 The direction cosines of a normal vector perpendicular to the saturation plane with respect to the patient. See C.7.6.2.1.1 for further explanation.
>Mid Slab Position (0018,9106) 1 The x, y, and z coordinates of the midpoint of the slab plane in mm with respect to the patient. See C.7.6.2.1.1 for further explanation.

C.8.13.5.12 MR Metabolite Map Macro

Table C.8-99 specifies the attributes of the MR Metabolite Map Functional Group macro.

TABLE C.8-99MR METABOLITE MAP MACRO ATTRIBUTES

Attribute Name Tag Type Attribute Description
MR Metabolite Map Sequence (0018,9152) 1 Describes the chemical shift parameters used to measure the resonant peaks from which the MR metabolite map represented by this frame was derived. Only a single Item shall be included in this sequence.
>Metabolite Map Description (0018,9080) 1C Text describing the Metabolite Map. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Metabolite Map Code Sequence (0018,9083) 3 When the measured peaks or their ratios can be related to metabolite substances, this sequence may be used to describe the metabolite substance whose resonant peaks are mapped in the Metabolite Map, or the ratio of substance resonant peaks that is mapped. Only a single Item shall be included in this sequence.
>>Include 'Code Sequence Macro' Table 8.8-1. Defined Context ID = 4032
>Chemical Shift Sequence (0018,9084) 3 The list of frequencies that were used to create the Metabolite Map. One or more Items are permitted in this sequence.
>>Chemical Shift Minimum Integration Limit in ppm (0018,9295) 1 Minimal value of Chemical Shift Frequency in ppm.
>>Chemical Shift Maximum Integration Limit in ppm (0018,9296) 1 Maximum value of Chemical Shift Frequency in ppm.

C.8.13.5.13 MR Velocity Encoding Macro

Table C.8-100 specifies the attributes of the MR Velocity Encoding Functional Group macro. This Functional Group contains the velocity encoding values as valid for the reconstructed Images, rather than for their acquisition. The velocity encoding directions for acquisition are described in the Velocity Encoding Acquisition Sequence (0018,9092) defined in the MR Pulse Sequence Module Section C.8.13.4.

Table C.8-100MR VELOCITY ENCODING MACRO ATTRIBUTES

Attribute Name Tag Type Attribute Description
MR Velocity Encoding Sequence (0018,9197) 1 Identifies the velocity encoding of this frame. One or more Items shall be included in this sequence.
>Velocity Encoding Direction (0018,9090) 1C The direction cosines of the velocity encoding vector with respect to the patient. See C.7.6.2.1.1 and C.8.13.5.13.1 for further explanation. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Velocity Encoding Minimum Value (0018,9091) 1C Minimum velocity in cm/s. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.
>Velocity Encoding Maximum Value (0018,9217) 1C Maximum velocity in cm/s. Required if Frame Type (0008,9007) Value 1 of this frame is ORIGINAL. May be present otherwise.

C.8.13.5.13.1 Velocity Encoding Direction

The direction of the flow in a flow image is defined by the direction of the relevant flow vector in the MR Velocity Encoding Sequence (0018, 9197).

The actual flow value (as specified in the Real World Value Mapping Sequence (0040,9096)) has a positive sign when the flow direction coincides with the Velocity Encoding Direction (0018,9090) vector.

C.8.13.5.14 MR Arterial Spin Labeling Macro

Table C.8-100b specifies the attributes of the MR Arterial Spin Labeling Functional Group macro.

Table C.8-100bMR ARTERIAL SPIN LABELING MACRO ATTRIBUTES

Attribute Name Tag Type Attribute Description
MR Arterial Spin Labeling Sequence (0018,9251) 1 A sequence that provides the position of Arterial Spin Labeling regions deposited as part of the pulse sequence. One or more items shall be included in this sequence.
>ASL Technique Description (0018,9252) 2 Text describing the used labeling technique in more detail.
>ASL Context (0018,9257) 1C The purpose of the Arterial Spin Labeling. Enumerated Values: LABEL CONTROL M_ZERO_SCAN Required if Frame Type (0008,9007) is ORIGINAL. May be present otherwise. See C.8.13.5.14.1 for further explanation.
>ASL Slab Sequence (0018,9260) 1C Sequence describing the ASL Slab geometry and anatomical region. One or more Items shall be included in this sequence. Required if ASL Context (0018,9257) is CONTROL or LABEL. May be present otherwise.
>>ASL Slab Number (0018,9253) 1 Consecutive number identifying the different slabs used for labeling, starting with 1.
>>Include ‘General Anatomy Optional Macro’ Table 10-7 The anatomical region where the slab is positioned. Defined Context ID for the Anatomic Region Sequence (0008,2218) is CID 4030. Defined Context ID for Anatomic Region Modifier Sequence (0008,2220) and Primary Anatomic Structure Modifier Sequence (0008,2230) is CID 2.
>>ASL Slab Thickness (0018,9254) 1 Thickness of slab in mm.
>>ASL Slab Orientation (0018,9255) 1 The direction cosines of a normal vector perpendicular to the ASL slab with respect to the patient. See C.7.6.2.1.1 for further explanation.
>>ASL Mid Slab Position (0018,9256) 1 The x, y, and z coordinates of the midpoint of the slab in mm with respect to the patient. See C.7.6.2.1.1 for further explanation.
>>ASL Pulse Train Duration (0018,9258) 1 Duration (in milliseconds) of the Label or Control pulse. See C.8.13.5.14.3 for further explanation.
>ASL Crusher Flag (0018,9259) 1 Indicates if an ASL Crusher Method has been used. Enumerated Values: YES NO See C.8.13.5.14.2 for further explanation.
>ASL Crusher Flow Limit (0018,925A) 1C Maximum Flow Limit (in cm/s). Required if ASL Crusher Flag (0018,9259) is YES.
>ASL Crusher Description (0018,925B) 1C Description of the ASL Crusher Method. Required if ASL Crusher Flag (0018,9259) is YES.
>ASL Bolus Cut-off Flag (0018,925C) 1 Indicates if a Bolus Cut-off technique is used. Enumerated Values: YES NO
>ASL Bolus Cut-off Timing Sequence (0018,925D) 1C Sequence that specifies the timing of the Bolus Cut-off technique and possibly its (scientific) description. Only a single Item shall be included in this sequence. Required if ASL Bolus Cut-off Flag (0018,925C) is YES.
>>ASL Bolus Cut-off Delay Time (0018,925F) 1 Bolus Cut-off pulse delay time (in ms). See C.8.13.5.14.3 for further explanation.
>>ASL Bolus Cut-off Technique (0018,925E) 2 Text describing the cut-off technique.

C.8.13.5.14.1 ASL Context

The attribute ASL Context (0018,9257) categorize the Original ASL images according to three contexts.  This categorization allows post processing applications to select the correct type of image.

LABEL: Images are acquired with magnetically labeled arterial blood supply.

CONTROL: Images are acquired with a 'control' pulse in the proximal vessels.

M_ZERO_SCAN: Images are acquired with no label or control pulse in the proximal vessels.

C.8.13.5.14.2 ASL Crusher Flag

In order to quantify the perfusion accurately, it may be necessary to suppress signals within the macroscopic blood vessels (crushing). This can be used to separate the arterial input function from the brain parenchymal signal. The ASL Crusher Flag (0018,9259) indicates the application of an ASL crushing technique.

Note: Frames with and without crushing may be present in one SOP Instance.

C.8.13.5.14.3 Relationship of ASL Timing Attributes

The general description of the ASL Acquisition technique requires a number of time related attributes that are depicted in Figure C.8.13.5.14-1.

[pic]

Figure C.8.13.5.14-1 Attributes for Quantitative ASL