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- # -*- coding: utf-8 -*-
- """
- A subroutine to add SPAIR fat suppression block.
- Requires the params structure as input.
- Need to think of the reequired output (pulse sequence variable itself?)
- @author: petrm
- """
- #imports
- from math import pi
- import numpy as np
- from MRI_sequences.pypulseq.make_delay import make_delay
- from MRI_sequences.pypulseq.make_gauss_pulse import make_gauss_pulse
- from MRI_sequences.pypulseq.make_trapezoid import make_trapezoid
- from MRI_sequences.pypulseq.calc_duration import calc_duration
- def SPAIR_block(params, scanner_parameters, gz90):
- #function creates CHESS saturation block with accompanied gx and gy spoiled gradients
- params['B0'] = 1.5 # TODO add to GUI
- params['FS_sat_ppm'] = -3.30 # TODO add to GUI
- params['FS_pulse_duration'] = 0.01 # TODO add to GUI
- #params['IR_time'] = 0.140 # SPAIR # TODO add to GUI
- params['BW_sat'] = -176.26464
- g_rf_area = gz90.area * 10
- FS_sat_frequency = params['B0'] * 1e-6 * params['FS_sat_ppm'] * params['gamma']
- flip_SPAIR = round(180 * pi / 180)
- rf_SPAIR = make_gauss_pulse(flip_angle=flip_SPAIR, system=scanner_parameters, duration=params['FS_pulse_duration'],
- bandwidth=abs(params['BW_sat']), freq_offset=FS_sat_frequency)
- gx_SPAIR = make_trapezoid(channel="x", system=scanner_parameters, delay=calc_duration(rf_SPAIR),
- area= g_rf_area, rise_time=params['dG'])
- gy_SPAIR = make_trapezoid(channel="y", system=scanner_parameters, delay=calc_duration(rf_SPAIR),
- area= g_rf_area, rise_time=params['dG'])
- delay_IR = np.ceil(params['TI'] / scanner_parameters.grad_raster_time) * scanner_parameters.grad_raster_time
- delay_IR = make_delay(delay_IR)
- return rf_SPAIR, gx_SPAIR, gy_SPAIR, delay_IR
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