B0 inhomogeneities occur at interfaces of materials with different magnetic susceptibilities,
Usage
ni_fsl_b0_calc(
in_file,
args = NULL,
chi_air = 4e-07,
compute_xyz = FALSE,
delta = -9.45e-06,
directconv = FALSE,
extendboundary = 1,
out_file = NULL,
x_b0 = 0,
x_grad = 0,
xyz_b0 = NULL,
y_b0 = 0,
y_grad = 0,
z_b0 = 1,
z_grad = 0,
.cwd = NULL,
.env = NULL,
.engine = NULL,
.profile = NULL,
dry_run = FALSE,
echo = interactive()
)Arguments
- in_file
Character; file path. filename of input image (usually a tissue/air segmentation) Required.
- args
Character. Additional parameters to the command
- chi_air
Numeric. susceptibility of air
- compute_xyz
Logical. calculate and save all 3 field components (i.e. x,y,z)
- delta
Numeric. Delta value (chi_tissue - chi_air)
- directconv
Logical. use direct (image space) convolution, not FFT
- extendboundary
Numeric. Relative proportion to extend voxels at boundary
- out_file
Character; file path. filename of B0 output volume
- x_b0
Numeric. Value for zeroth-order b0 field (x-component), in Tesla
- x_grad
Numeric. Value for zeroth-order x-gradient field (per mm)
- xyz_b0
Character or numeric vector. Zeroth-order B0 field in Tesla
- y_b0
Numeric. Value for zeroth-order b0 field (y-component), in Tesla
- y_grad
Numeric. Value for zeroth-order y-gradient field (per mm)
- z_b0
Numeric. Value for zeroth-order b0 field (z-component), in Tesla
- z_grad
Numeric. Value for zeroth-order z-gradient field (per mm)
- .cwd
Working directory override.
- .env
Named character vector of environment variables.
- .engine
Execution engine override.
- .profile
Runtime profile override.
- dry_run
Logical; preview command without executing.
- echo
Logical; echo stdout/stderr in real time.