.. DO NOT EDIT. .. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY. .. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE: .. "generated/gallery/10-gradient-echo/gre_radial2D_sequence.py" .. LINE NUMBERS ARE GIVEN BELOW. .. only:: html .. note:: :class: sphx-glr-download-link-note :ref:`Go to the end ` to download the full example code. .. rst-class:: sphx-glr-example-title .. _sphx_glr_generated_gallery_10-gradient-echo_gre_radial2D_sequence.py: ========================= 2D radial gradient echo ========================= A spoiled low-flip-angle excitation is followed by one radial spoke through k-space centre. Gradient and RF spoiling suppress residual transverse coherence before the next TR. TR and flip angle primarily determine T1 weighting, with T2* decay during TE. Radial SPGR is used for motion-robust dynamic and structural imaging. .. GENERATED FROM PYTHON SOURCE LINES 12-32 .. GENERATED FROM PYTHON SOURCE LINES 33-38 Nyquist angular sampling ------------------------ ``ceil(pi / 2 * n)`` spokes over half a turn, which sample the outer radius at the Nyquist spacing. .. GENERATED FROM PYTHON SOURCE LINES 38-46 .. code-block:: Python import pypulseqpp as pp from pypulseqpp.sequences import gre_radial2D_sequence baseline = gre_radial2D_sequence(n=192, n_slices=1, te=None, tr=None, n_dummy=0) print(f"{baseline.num_blocks} blocks, {baseline.duration()[0]:.2f} s") .. rst-class:: sphx-glr-script-out .. code-block:: none 1208 blocks, 3.13 s .. GENERATED FROM PYTHON SOURCE LINES 47-49 Sequence diagram ---------------- .. GENERATED FROM PYTHON SOURCE LINES 49-52 .. code-block:: Python baseline.paper_plot() .. image-sg:: /generated/gallery/10-gradient-echo/images/sphx_glr_gre_radial2D_sequence_001.png :alt: gre radial2D sequence :srcset: /generated/gallery/10-gradient-echo/images/sphx_glr_gre_radial2D_sequence_001.png :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 53-58 Sampling order -------------- Colour encodes spoke acquisition order. Consecutive spokes use a distributed angular ordering rather than adjacent angles. .. GENERATED FROM PYTHON SOURCE LINES 58-61 .. code-block:: Python pp.plot.plot_kspace(baseline, color_by="shot", plane="xy") .. image-sg:: /generated/gallery/10-gradient-echo/images/sphx_glr_gre_radial2D_sequence_002.png :alt: gre radial2D sequence :srcset: /generated/gallery/10-gradient-echo/images/sphx_glr_gre_radial2D_sequence_002.png :class: sphx-glr-single-img .. GENERATED FROM PYTHON SOURCE LINES 62-67 Angular undersampling --------------------- ``ry=3`` retains one third of the spoke angles. Every spoke crosses the origin, whereas angular sampling density decreases with k-space radius. .. GENERATED FROM PYTHON SOURCE LINES 67-81 .. code-block:: Python alternative = gre_radial2D_sequence( n=192, n_slices=1, ry=3, te=None, tr=None, n_dummy=0 ) .. rst-class:: sphx-glr-script-out .. code-block:: none blocks duration (s) acquisitions Nyquist 1208 3.13 302 ry = 3 404 1.05 101 .. GENERATED FROM PYTHON SOURCE LINES 82-84 .. code-block:: Python pp.plot.plot_kspace(alternative, color_by="shot", plane="xy") .. image-sg:: /generated/gallery/10-gradient-echo/images/sphx_glr_gre_radial2D_sequence_003.png :alt: gre radial2D sequence :srcset: /generated/gallery/10-gradient-echo/images/sphx_glr_gre_radial2D_sequence_003.png :class: sphx-glr-single-img .. rst-class:: sphx-glr-timing **Total running time of the script:** (0 minutes 2.692 seconds) .. _sphx_glr_download_generated_gallery_10-gradient-echo_gre_radial2D_sequence.py: .. only:: html .. container:: sphx-glr-footer sphx-glr-footer-example .. container:: sphx-glr-download sphx-glr-download-jupyter :download:`Download Jupyter notebook: gre_radial2D_sequence.ipynb ` .. container:: sphx-glr-download sphx-glr-download-python :download:`Download Python source code: gre_radial2D_sequence.py ` .. container:: sphx-glr-download sphx-glr-download-zip :download:`Download zipped: gre_radial2D_sequence.zip ` .. only:: html .. rst-class:: sphx-glr-signature `Gallery generated by Sphinx-Gallery `_