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.

Table C.7.6.18-1 CARDIAC SYNCHRONIZATION MODULE ATTRIBUTES

Attribute Name Tag Type Attribute Description
Cardiac Synchronization Technique (0018,9037) 1C Defines if a cardiac synchronization technique was applied during or after the acquisition. Enumerated Values: NONE REALTIME = total time for the acquisition is shorter than cardiac cycle, no gating is applied PROSPECTIVE = certain thresholds have been set for a gating window that defines the acceptance of measurement data during the acquisition RETROSPECTIVE = certain thresholds have been set for a gating window that defines the acceptance of measurement data after the acquisition PACED = there is a constant RR interval (e.g., Pacemaker), which makes thresholding not required Required if Image Type (0008,0008) Value 1 is ORIGINAL or MIXED. May be present otherwise.
Cardiac Signal Source (0018,9085) 1C Cardiac Signal Source. Defined Terms: ECG = electrocardiogram VCG = vector cardiogram PP = peripheral pulse MR = magnetic resonance, i.e. M-mode or cardiac navigator Required if Image Type (0008,0008) Value 1 is ORIGINAL or MIXED and Cardiac Synchronization Technique (0018,9037) equals other than NONE. Otherwise may be present if Image Type (0008,0008) Value 1 is DERIVED and Cardiac Synchronization Technique (0018,9037) equals other than NONE.
Cardiac RR Interval Specified (0018,9070) 1C R-R interval in ms measured prior to or during the scan. Required if Image Type (0008,0008) Value 1 is ORIGINAL or MIXED and Cardiac Synchronization Technique (0018,9037) equals other than NONE. Otherwise may be present if Image Type (0008,0008) Value 1 is DERIVED and Cardiac Synchronization Technique (0018,9037) equals other than NONE. Note: The Heart Rate (0018,1088) attribute is not used in this Module, since its value can be derived as 1/ Cardiac RR Interval Specified (0018,9070).
Cardiac Beat Rejection Technique (0018,9169) 1C Cardiac arrhythmia rejection technique. Defined Terms: NONE RR_INTERVAL = rejection based on deviation from average RR interval QRS_LOOP = rejection based on deviation from regular QRS loop PVC = rejection based on PVC criteria Required if Image Type (0008,0008) Value 1 is ORIGINAL or MIXED and Cardiac Synchronization Technique (0018,9037) equals PROSPECTIVE or RETROSPECTIVE. Otherwise may be present if Image Type (0008,0008) Value 1 is DERIVED and Cardiac Synchronization Technique (0018,9037) equals PROSPECTIVE or RETROSPECTIVE.
Low R-R Value (0018,1081) 2C R-R interval low limit for beat rejection, in ms. Required if Image Type (0008,0008) Value 1 is ORIGINAL or MIXED and Cardiac Synchronization Technique (0018,9037) equals PROSPECTIVE or RETROSPECTIVE. Otherwise may be present if Image Type (0008,0008) Value 1 is DERIVED and Cardiac Synchronization Technique (0018,9037) equals PROSPECTIVE or RETROSPECTIVE.
High R-R Value (0018,1082) 2C R-R interval high limit for beat rejection, in ms. Required if Image Type (0008,0008) Value 1 is ORIGINAL or MIXED and Cardiac Synchronization Technique (0018,9037) equals PROSPECTIVE or RETROSPECTIVE. Otherwise may be present if Image Type (0008,0008) Value 1 is DERIVED and Cardiac Synchronization Technique (0018,9037) equals PROSPECTIVE or RETROSPECTIVE.
Intervals Acquired (0018,1083) 2C Number of R-R intervals acquired and used to create the image (not including the intervals rejected). Required if Image Type (0008,0008) Value 1 is ORIGINAL or MIXED and Cardiac Synchronization Technique (0018,9037) equals other than NONE. Otherwise may be present if Image Type (0008,0008) Value 1 is DERIVED and Cardiac Synchronization Technique (0018,9037) equals other than NONE.
Intervals Rejected (0018,1084) 2C Number of R-R intervals rejected. Required if Image Type (0008,0008) Value 1 is ORIGINAL or MIXED and Cardiac Synchronization Technique (0018,9037) equals other than NONE. Otherwise may be present if Image Type (0008,0008) Value 1 is DERIVED and Cardiac Synchronization Technique (0018,9037) equals other than NONE.
Skip Beats (0018,1086) 3 Number of beats prescribed to be skipped after each detected arrhythmia.
Cardiac Framing Type (0018,1064) 1C Description of type of framing performed. See C.7.6.18.1.1.1 for description and Defined Terms. Required if type of framing is not time forward from trigger, may be present otherwise.

Note: Low R-R Value (0018,1081), High R-R Value (0018,1082), Intervals Acquired (0018,1083) and Intervals Rejected (0018,1084) in this Module apply to the entire Image. The Cardiac Gating Sequence (0018,9118) in the Cardiac Gating Functional Group uses the same attributes and specifies the values for a single frame.

C.7.6.18.1.1 Attribute Descriptions

C.7.6.18.1.1.1 Cardiac Framing Type

Cardiac Framing Type (0018,1064) is the mechanism used to select the data acquired to construct the frames within a specified cardiac timing interval.

Defined Terms:

FORW = time forward from trigger

BACK = time back before trigger

PCNT = percentage of R-R forward from trigger

C.7.6.18.2 Respiratory Synchronization Module

Table C7.6.18-2 specifies the attributes of the Respiratory Synchronization Module.

Table C.7.6.18-2RESPIRATORY SYNCHRONIZATION MODULE ATTRIBUTES

Attribute Name Tag Type Attribute Description
Respiratory Motion Compensation Technique (0018,9170) 1C Applied technique to reduce respiratory motion artifacts. Defined Terms: NONE BREATH_HOLD REALTIME = image acquisition shorter than respiratory cycle GATING = Prospective gating TRACKING = prospective through-plane or in-plane motion tracking PHASE_ORDERING = prospective phase ordering PHASE_RESCANNING = prospective techniques, such as real-time averaging, diminishing variance and motion adaptive gating RETROSPECTIVE = retrospective gating CORRECTION = retrospective image correction Required if Image Type (0008,0008) Value 1 is ORIGINAL or MIXED. May be present otherwise.
Respiratory Signal Source (0018,9171) 1C Signal source from which respiratory motion is derived. Defined Terms: NONE BELT = includes various devices that detect or track expansion of the chest NASAL_PROBE CO2_SENSOR NAVIGATOR = MR navigator and organ edge detection MR_PHASE = phase (of center k-space line) ECG = baseline demodulation of the ECG Required if Image Type (0008,0008) Value 1 is ORIGINAL or MIXED and Respiratory Motion Compensation Technique (0018,9170) equals other than NONE. Otherwise may be present if Image Type (0008,0008) Value 1 is DERIVED and Respiratory Motion Compensation Technique (0018,9170 equals other than NONE.
Respiratory Trigger Delay Threshold (0020,9256) 1C Respiratory trigger threshold in percent of the chest expansion for the frame relative to the last Respiratory-Peak. See C.7.6.16.2.17.1 for further explanation. Required if Respiratory Motion Compensation Technique (0018,9170) equals other than NONE, REALTIME or BREATH_HOLD and if Image Type (0008,0008) Value 1 is ORIGINAL or MIXED. May be present otherwise.
Respiratory Trigger Type (0020,9250) 1C Characteristic of the respiratory signal used to the define the respiratory triggering. Defined Terms: TIME AMPLITUDE BOTH Required if the value is not TIME, may be present otherwise.

C.7.6.18.3 Bulk Motion Synchronization Module

Table C7.6.18-3 specifies the attributes of the Bulk Motion Synchronization Module.

Table C.7.6.18-3BULK MOTION SYNCHRONIZATION MODULE ATTRIBUTES

Attribute Name Tag Type Attribute Description
Bulk Motion Compensation Technique (0018,9172) 1C Applied technique to reduce bulk or other physiology motion artifacts. Defined Terms: NONE REALTIME = image acquisition shorter than motion cycle GATING = prospective gating TRACKING = prospective through and/or in-plane motion tracking RETROSPECTIVE = retrospective gating CORRECTION = retrospective image correction Required if Image Type (0008,0008) Value 1 is ORIGINAL or MIXED. May be present otherwise.
Bulk Motion Signal Source (0018,9173) 1C Signal source to measure motion. Defined Terms: JOINT = joint motion detection NAVIGATOR = MR navigator and organ edge detection MR_PHASE = phase (of center k-space line) Required if Image Type (0008,0008) Value 1 is ORIGINAL or MIXED and Bulk Motion Compensation Technique (0018,9172) equals other than NONE. Otherwise may be present if Image Type (0008,0008) Value 1 is DERIVED and Bulk Motion Compensation Technique (0018,9172) equals other than NONE.