mrsd: a toolkit to generate MR sequence diagrams

mrsd is a Python toolkit to generate MR sequence diagrams, as shown below for the basic FLASH sequence.

FLASH sequence diagram generated with mrsd

mrsd is based on Matplotlib and additionally requires numpy. The code which generated the previous diagram is available in the examples direction, and an excerpt is shown below.

figure, plot = matplotlib.pyplot.subplots()
diagram = mrsd.Diagram(
    plot, ["RF", "$G_{slice}$", "$G_{phase}$", "$G_{readout}$", "Signal"])

# Slice-selective pulse of the first TR
diagram.sinc_pulse("RF", 0, RF_duration, 1)
diagram.gradient("$G_{slice}$", *RF[0], selection)
diagram.idle(["$G_{phase}$", "$G_{readout}$", "Signal"], *RF[0])

# Dead time until the start of encoding
diagram.idle_all(RF[0][1], encoding[0])

# Encoding: rewind slice-selection gradient, run phase gradient, prephase
# read-out gradient
diagram.gradient("$G_{slice}$", *encoding, rewind)
diagram.stepped_gradient("$G_{phase}$", *encoding, 1)
diagram.gradient("$G_{readout}$", *encoding, prephasing)
diagram.idle(["RF", "Signal"], *encoding)

# Readout, centered on TE
diagram.gradient("$G_{readout}$", *readout, dephasing)
diagram.readout("Signal", *readout, +1)
diagram.idle(["RF", "$G_{slice}$", "$G_{phase}$"], *readout)

# Idle until end of TR
diagram.idle_all(readout[1], RF[1][0])

# Start of next TR
diagram.sinc_pulse("RF", TR, RF_duration, 1)
diagram.gradient("$G_{slice}$", *RF[1], selection)
diagram.idle(["$G_{phase}$", "$G_{readout}$", "Signal"], *RF[1])
diagram.idle_all(TR+RF_duration/2, TR+RF_duration)

# Add annotations: flip angles and TE/TR intervals
diagram.annotate("RF", 0.2, r"$\alpha$", 1)
diagram.annotate("RF", TR+0.2, r"$\alpha$", 1)
diagram.interval(0, TE, -1.5, "TE", 10)
diagram.interval(0, TR, -2.5, "TR", 10)

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