Sample Sequence
The code below shows how the famous “MiniFLASH” sequence can be expressed using the mtrk SDL. In this formulation, the amplitude of the phase-encoding gradient is varied using an equation. Alternatively, the gradient amplitude could also be stored and read from an array using the line-counter as index.
{
"file": {
"format": "mtrk-SDL",
"version": 1,
"measurement": "abc",
"system": "Skyra-XQ"
},
"settings": {
"readout_os": 2
},
"infos": {
"description": "MiniFlash equivalent",
"slices": 1,
"fov": 300,
"seqstring": "YARRA",
"reconstruction": "%SiemensIceProgs%\\IceProgram2D"
},
"instructions": {
"main": {
"steps": [
{
"action": "loop",
"counter": 1,
"range": 128,
"steps": [
{
"action": "run_block",
"block": "block_TR"
}
]
}
]
},
"block_TR": {
"steps": [
{
"action": "calc",
"type": "float_rfspoil",
"float": 0,
"increment": 50
},
{
"action": "init",
"gradients": "logical"
},
{
"action": "sync",
"object": "ttl",
"time": 0
},
{
"action": "grad",
"axis": "slice",
"object": "grad_slice_select",
"time": 0
},
{
"action": "rf",
"object": "rf_excitation",
"time": 100,
"added_phase": {
"type": "float",
"float": 0
}
},
{
"action": "grad",
"axis": "read",
"object": "grad_read_dephase",
"time": 2660
},
{
"action": "grad",
"axis": "phase",
"object": "grad_phase_encode",
"time": 2660,
"amplitude": {
"type": "equation",
"equation": "phaseencoding"
}
},
{
"action": "grad",
"axis": "slice",
"object": "grad_slice_refocus",
"time": 2760
},
{
"action": "grad",
"axis": "read",
"object": "grad_read_readout",
"time": 9430
},
{
"action": "adc",
"object": "adc_readout",
"time": 9460,
"frequency": 0,
"phase": 0,
"added_phase": {
"type": "float",
"float": 0
},
"mdh": {
"line": {
"type": "counter",
"counter": 1
},
"first_scan_slice": {
"type": "counter",
"counter": 1,
"target": 0
},
"first_scan_slice": {
"type": "counter",
"counter": 1,
"target": 0
},
"last_scan_slice": {
"type": "counter",
"counter": 1,
"target": 127
}
}
},
{
"action": "grad",
"axis": "phase",
"object": "grad_phase_encode",
"time": 13300,
"amplitude": "flip"
},
{
"action": "grad",
"axis": "slice",
"object": "grad_slice_refocus",
"time": 13300,
"amplitude": "flip"
},
{
"action": "mark",
"time": 20000
},
{
"action": "submit"
}
]
}
},
"objects": {
"rf_excitation": {
"type": "rf",
"array": "rfpulse",
"duration": 2560,
"initial_phase": 0,
"thickness": 5,
"flipangle": 15,
"purpose": "excitation"
},
"grad_slice_select": {
"type": "grad",
"array": "grad_100_2560_100",
"duration": 2660,
"tail": 0,
"amplitude": 4.95
},
"grad_slice_refocus": {
"type": "grad",
"array": "grad_220_80_220",
"duration": 300,
"tail": 0,
"amplitude": -21.96
},
"grad_read_dephase": {
"type": "grad",
"array": "grad_220_10_220",
"duration": 230,
"tail": 0,
"amplitude": -21.96
},
"grad_read_readout": {
"type": "grad",
"array": "grad_30_3840_30",
"duration": 3870,
"tail": 0,
"amplitude": 2.61
},
"grad_phase_encode": {
"type": "grad",
"array": "grad_220_10_220",
"duration": 230,
"tail": 0,
"amplitude": 10
},
"adc_readout": {
"type": "adc",
"duration": 3840,
"samples": 128,
"dwelltime": 30000
},
"ttl": {
"type": "sync",
"duration": 10,
"event": "osc0"
}
},
"arrays": {
"rfpulse": {
"size": 128,
"type": "complex_float",
"encoding": "text",
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},
"grad_100_2560_100": {
"encoding": "text",
"type": "float",
"size": 276,
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},
"grad_220_10_220": {
"encoding": "text",
"type": "float",
"size": 45,
"data": [0.0, 0.0455, 0.0909, 0.1364, 0.1818, 0.2273, 0.2727, 0.3182, 0.3636, 0.4091, 0.4545, 0.5, 0.5455, 0.5909, 0.6364, 0.6818, 0.7273, 0.7727, 0.8182, 0.8636, 0.9091, 0.9545, 1.0, 0.9545, 0.9091, 0.8636, 0.8182, 0.7727, 0.7273, 0.6818, 0.6364, 0.5909, 0.5455, 0.5, 0.4545, 0.4091, 0.3636, 0.3182, 0.2727, 0.2273, 0.1818, 0.1364, 0.0909, 0.0455, 0.0]
},
"grad_220_80_220": {
"encoding": "text",
"type": "float",
"size": 52,
"data": [0.0, 0.0455, 0.0909, 0.1364, 0.1818, 0.2273, 0.2727, 0.3182, 0.3636, 0.4091, 0.4545, 0.5, 0.5455, 0.5909, 0.6364, 0.6818, 0.7273, 0.7727, 0.8182, 0.8636, 0.9091, 0.9545, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 0.9545, 0.9091, 0.8636, 0.8182, 0.7727, 0.7273, 0.6818, 0.6364, 0.5909, 0.5455, 0.5, 0.4545, 0.4091, 0.3636, 0.3182, 0.2727, 0.2273, 0.1818, 0.1364, 0.0909, 0.0455, 0.0]
},
"grad_30_3840_30": {
"encoding": "text",
"type": "float",
"size": 390,
"data": [0.0, 0.3333, 0.6667, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 0.6667, 0.3333, 0.0]
}
},
"equations": {
"phaseencoding": {
"equation": "0.3378125*(ctr(1)-64.5)"
}
}
}