BrainWeb.isochromats

BrainWeb.isochromats()

Return the brain sampled as isochromats, for simulate().

The voxels are averaged in cubes spacing wide. Each tissue a cube holds is spins isochromats of proton density, between them, the tissue’s times the fraction of the cube it fills times the cube’s volume in m³, precessing at the cube’s mean field_ppm: at the cube’s centre, or over the cube for a "box" voxel, and at the quantiles of the Lorentzian line of the tissue’s T2’ (Bloch engine).

Parameters:

• spacing – Width of a cube, in metres: a whole number of millimetres.

• field_t – The magnet’s field, in T, at which fat’s chemical shift is resolved into a frequency, with pypulseqpp’s default gamma.

• off_resonance_hz – Frequency of every isochromat from the scanner’s centre frequency, in Hz, beside its chemical shift.

• region – Which isochromats are kept, from their (n, 3) positions, in m, and (n,) frequencies, in Hz, as Slabs answers; the whole head without one.

• coil – The scanner’s coil the brain is scanned with, in place of the phantom’s coils.

• spins – Isochromats per tissue of a cube: a cube number for a "box".

• voxel – "point" or "box": where a cube’s isochromats lie.

• motion – The head’s motion, as Isochromats takes it.

• seed – Seed of the frequencies of each voxel’s isochromats and of their Brownian walks.

• threads – Worker threads of the simulation; 0 for every core.

• device – The device the ADC windows are read and the runs of repetitions carried on, as Isochromats takes it; the engine does both itself without one.

Raises:

ValueError – If spacing is not a whole number of millimetres, field_t is not given, the brain has coils of its own and coil is given, or spins do not fill a voxel.