C.8.3.1 MR Image Module

Table C.8-4 contains the Attributes that describe MR images.

Table C.8-4MR IMAGE MODULE ATTRIBUTES

Attribute Name Tag Type Attribute Description
Image Type (0008,0008) 1 Image identification characteristics. See C.8.3.1.1.1 for specialization.
Samples per Pixel (0028,0002) 1 Number of samples (planes) in this image. See C.8.3.1.1.2 for specialization.
Photometric Interpretation (0028,0004) 1 Specifies the intended interpretation of the pixel data. See C.8.3.1.1.3 for specialization.
Bits Allocated (0028,0100) 1 Number of bits allocated for each pixel sample. Each sample shall have the same number of bits allocated. See C.8.3.1.1.4 for specialization.
Scanning Sequence (0018,0020) 1 Description of the type of data taken. Enumerated Values: SE = Spin Echo IR = Inversion Recovery GR = Gradient Recalled EP = Echo Planar RM = Research Mode Note: Multi-valued, but not all combinations are valid (e.g. SE/GR, etc.).
Sequence Variant (0018,0021) 1 Variant of the Scanning Sequence. Defined Terms: SK = segmented k-space MTC = magnetization transfer contrast SS = steady state TRSS = time reversed steady state SP = spoiled MP = MAG prepared OSP = oversampling phase NONE = no sequence variant
Scan Options (0018,0022) 2 Parameters of scanning sequence. Defined Terms: PER = Phase Encode Reordering RG = Respiratory Gating CG = Cardiac Gating PPG = Peripheral Pulse Gating FC = Flow Compensation PFF = Partial Fourier - Frequency PFP = Partial Fourier - Phase SP = Spatial Presaturation FS = Fat Saturation
MR Acquisition Type (0018,0023) 2 Identification of data encoding scheme. Enumerated Values: 2D = frequency x phase 3D = frequency x phase x phase
Repetition Time (0018,0080) 2C The period of time in msec between the beginning of a pulse sequence and the beginning of the succeeding (essentially identical) pulse sequence. Required except when Scanning Sequence (0018,0020) is EP and Sequence Variant (0018,0021) is not SK.
Echo Time (0018,0081) 2 Time in ms between the middle of the excitation pulse and the peak of the echo produced (kx=0). In the case of segmented k-space, the TE(eff) is the time between the middle of the excitation pulse to the peak of the echo that is used to cover the center of k-space (i.e.-kx=0, ky=0).
Echo Train Length (0018,0091) 2 Number of lines in k-space acquired per excitation per image.
Inversion Time (0018,0082) 2C Time in msec after the middle of inverting RF pulse to middle of excitation pulse to detect the amount of longitudinal magnetization. Required if Scanning Sequence (0018,0020) has values of IR.
Trigger Time (0018,1060) 2C Time, in msec, between peak of the R wave and the peak of the echo produced. In the case of segmented k-space, the TE(eff) is the time between the peak of the echo that is used to cover the center of k-space. Required for Scan Options (0018,0022) which include heart gating (e.g. CG, PPG, etc.)
Sequence Name (0018,0024) 3 User defined name for the Scanning Sequence (0018,0020) and Sequence Variant (0018,0021) combination.
Angio Flag (0018,0025) 3 Angio Image Indicator. Primary image for Angio processing. Enumerated Values: Y = Image is Angio N = Image is not Angio
Number of Averages (0018,0083) 3 Number of times a given pulse sequence is repeated before any parameter is changed
Imaging Frequency (0018,0084) 3 Precession frequency in MHz of the nucleus being addressed
Imaged Nucleus (0018,0085) 3 Nucleus that is resonant at the imaging frequency. Examples: 31P, 1H
Echo Number (0018,0086) 3 The echo number used in generating this image. In the case of segmented k-space, it is the effective Echo Number.
Magnetic Field Strength (0018,0087) 3 Nominal field strength of MR magnet, in Tesla
Spacing Between Slices (0018,0088) 3 Spacing between slices, in mm. The spacing is measured from the center-to-center of each slice.
Number of Phase Encoding Steps (0018,0089) 3 Total number of lines in k-space in the 'y' direction collected during acquisition.
Percent Sampling (0018,0093) 3 Fraction of acquisition matrix lines acquired, expressed as a percent.
Percent Phase Field of View (0018,0094) 3 Ratio of field of view dimension in phase direction to field of view dimension in frequency direction, expressed as a percent.
Pixel Bandwidth (0018,0095) 3 Reciprocal of the total sampling period, in hertz per pixel.
Nominal Interval (0018,1062) 3 Average R-R interval used for the scans, in msec
Beat Rejection Flag (0018,1080) 3 Beat length sorting has been applied. Enumerated Values: Y = yes N = No
Low R-R Value (0018,1081) 3 R-R interval low limit for beat rejection, in msec
High R-R Value (0018,1082) 3 R-R interval high limit for beat rejection, in msec
Intervals Acquired (0018,1083) 3 Number of R-R intervals acquired.
Intervals Rejected (0018,1084) 3 Number of R-R intervals rejected.
PVC Rejection (0018,1085) 3 Description of type of PVC rejection criteria used.
Skip Beats (0018,1086) 3 Number of beats skipped after a detected arrhythmia.
Heart Rate (0018,1088) 3 Beats per minute.
Cardiac Number of Images (0018,1090) 3 Number of images per cardiac cycle.
Trigger Window (0018,1094) 3 Percent of R-R interval, based on Heart Rate (0018,1088), prescribed as a window for a valid/usable trigger.
Reconstruction Diameter (0018,1100) 3 Diameter in mm. of the region from within which data were used in creating the reconstruction of the image. Data may exist outside this region and portions of the patient may exist outside this region.
Receive Coil Name (0018,1250) 3 Receive coil used.
Transmit Coil Name (0018,1251) 3 Transmit coil used.
Acquisition Matrix (0018,1310) 3 Dimensions of the acquired frequency /phase data before reconstruction. Multi-valued: frequency rows\frequency columns\phase rows\phase columns.
In-plane Phase Encoding Direction (0018,1312) 3 The axis of phase encoding with respect to the image. Enumerated Values: ROW = phase encoded in rows. COL = phase encoded in columns.
Flip Angle (0018,1314) 3 Steady state angle in degrees to which the magnetic vector is flipped from the magnetic vector of the primary field.
SAR (0018,1316) 3 Calculated whole body Specific Absorption Rate in watts/kilogram.
Variable Flip Angle Flag (0018,1315) 3 Flip angle variation applied during image acquisition. Enumerated Values: Y = yes N = no
dB/dt (0018,1318) 3 The rate of change of the gradient coil magnetic flux density with time (T/s).
Temporal Position Identifier (0020,0100) 3 Temporal order of a dynamic or functional set of Images.
Number of Temporal Positions (0020,0105) 3 Total number of temporal positions prescribed.
Temporal Resolution (0020,0110) 3 Time delta between Images in a dynamic or functional set of Images.
Include 'General Anatomy Optional Macro' Table 10-7 Defined Context ID for the Anatomic Region Sequence is 4030.

C.8.3.1.1 MR Image Attribute Descriptions

C.8.3.1.1.1 Image Type

For MR Images, Image Type (0008,0008) is specified to be Type 1 and use one of the following Defined Terms for Value 3:

MPR PROJECTION IMAGE T1 MAP
T2 MAP DIFFUSION MAP DENSITY MAP
PHASE MAP VELOCITY MAP IMAGE ADDITION
PHASE SUBTRACT MODULUS SUBTRACT OTHER

C.8.3.1.1.2 Samples Per Pixel

For MR Images, Samples per Pixel (0028,0002) shall have an Enumerated Value of 1.

C.8.3.1.1.3 Photometric Interpretation

For MR Images, Photometric Interpretation (0028,0004) shall have one of the following Enumerated Values:

MONOCHROME1

MONOCHROME2

See C.7.6.3.1.2 for definition of these terms.

C.8.3.1.1.4 Bits Allocated

For MR Images, Bits Allocated (0028,0100) shall have the Enumerated Value of 16.