physics_based_augmentation/seqgen/pypulseq/tests/test_sigpy.py

# sms - check MB
# slr - check slice profile

import unittest

import numpy as np
import sigpy.mri.rf as rf

from pypulseq.make_sigpy_pulse import sigpy_n_seq
from pypulseq.opts import Opts
from pypulseq.sigpy_pulse_opts import SigpyPulseOpts


class TestSigpyPulseMethods(unittest.TestCase):
    def test_slr(self):
        print("Testing SLR design")

        time_bw_product = 4
        slice_thickness = 3e-3  # Slice thickness
        flip_angle = np.pi / 2
        # Set system limits
        system = Opts(
            max_grad=32,
            grad_unit="mT/m",
            max_slew=130,
            slew_unit="T/m/s",
            rf_ringdown_time=30e-6,
            rf_dead_time=100e-6,
        )
        pulse_cfg = SigpyPulseOpts(
            pulse_type="slr",
            ptype="st",
            ftype="ls",
            d1=0.01,
            d2=0.01,
            cancel_alpha_phs=False,
            n_bands=3,
            band_sep=20,
            phs_0_pt="None",
        )
        rfp, gz, _, pulse = sigpy_n_seq(
            flip_angle=flip_angle,
            system=system,
            duration=3e-3,
            slice_thickness=slice_thickness,
            time_bw_product=4,
            return_gz=True,
            pulse_cfg=pulse_cfg,
        )

        [a, b] = rf.sim.abrm(
            pulse,
            np.arange(
                -20 * time_bw_product, 20 * time_bw_product, 40 * time_bw_product / 2000
            ),
            True,
        )
        Mxy = 2 * np.multiply(np.conj(a), b)
        # pl.LinePlot(Mxy)
        # print(np.sum(np.abs(Mxy)))
        # peaks, dict = sis.find_peaks(np.abs(Mxy),threshold=0.5, plateau_size=40)
        plateau_widths = np.sum(np.abs(Mxy) > 0.8)
        self.assertTrue(29, plateau_widths)

    def test_sms(self):
        print("Testing SMS design")

        time_bw_product = 4
        slice_thickness = 3e-3  # Slice thickness
        flip_angle = np.pi / 2
        n_bands = 3
        # Set system limits
        system = Opts(
            max_grad=32,
            grad_unit="mT/m",
            max_slew=130,
            slew_unit="T/m/s",
            rf_ringdown_time=30e-6,
            rf_dead_time=100e-6,
        )
        pulse_cfg = SigpyPulseOpts(
            pulse_type="sms",
            ptype="st",
            ftype="ls",
            d1=0.01,
            d2=0.01,
            cancel_alpha_phs=False,
            n_bands=n_bands,
            band_sep=20,
            phs_0_pt="None",
        )
        rfp, gz, _, pulse = sigpy_n_seq(
            flip_angle=flip_angle,
            system=system,
            duration=3e-3,
            slice_thickness=slice_thickness,
            time_bw_product=4,
            return_gz=True,
            pulse_cfg=pulse_cfg,
        )

        [a, b] = rf.sim.abrm(
            pulse,
            np.arange(
                -20 * time_bw_product, 20 * time_bw_product, 40 * time_bw_product / 2000
            ),
            True,
        )
        Mxy = 2 * np.multiply(np.conj(a), b)
        # pl.LinePlot(Mxy)
        # print(np.sum(np.abs(Mxy)))
        # peaks, dict = sis.find_peaks(np.abs(Mxy),threshold=0.5, plateau_size=40)
        plateau_widths = np.sum(np.abs(Mxy) > 0.8)
        self.assertEqual(
            29 * n_bands, plateau_widths
        )  # if slr has 29 > 0.8, then sms with MB = n_bands


if __name__ == "__main__":
    unittest.main()