SWI (2D Hamming)

Algorithm parameters overview

algorParam.swismwi.	Description
m	Power to which the phase mask is raised, controlling the contrast/strength of the phase weighting applied to the magnitude image
threshold	Phase threshold (in radians) used to build the phase mask from the unwrapped/high-pass filtered phase
filterSize	Size of the 2D low-pass (Hamming) filter kernel, in voxels, used to remove the background phase before computing the phase mask
method	Echo/phase combination method used to compute the SWI phase mask
ismIP	Enable minimum intensity projection (mIP) of the SWI image over a number of slices
slice_mIP	Number of slices used to compute the minimum intensity projection (mIP), when ismIP is enabled
isPositive	Save the positive (bright, e.g. paramagnetic contrast) phase-weighted SWI images
isNegative	Save the negative (dark, e.g. diamagnetic contrast) phase-weighted SWI images

Usage

algorParam.swismwi.m

Power to which the phase mask is raised, controlling the contrast/strength of the phase weighting applied to the magnitude image

Default Value: 4

Examples:

algorParam.swismwi.m = 1;

algorParam.swismwi.m = 4;

algorParam.swismwi.m = 8;

algorParam.swismwi.threshold

Phase threshold (in radians) used to build the phase mask from the unwrapped/high-pass filtered phase

Default Value: pi

Examples:

algorParam.swismwi.threshold = pi/2;

algorParam.swismwi.threshold = pi;

algorParam.swismwi.threshold = 2*pi;

algorParam.swismwi.filterSize

Size of the 2D low-pass (Hamming) filter kernel, in voxels, used to remove the background phase before computing the phase mask

Default Value: 12

Examples:

algorParam.swismwi.filterSize = 4;

algorParam.swismwi.filterSize = 12;

algorParam.swismwi.filterSize = 32;

algorParam.swismwi.method

Echo/phase combination method used to compute the SWI phase mask

Default Value: ‘default’

Examples:

algorParam.swismwi.method = 'default';

algorParam.swismwi.ismIP

Enable minimum intensity projection (mIP) of the SWI image over a number of slices

Default Value: true

Examples:

algorParam.swismwi.ismIP = true;

algorParam.swismwi.ismIP = false;

algorParam.swismwi.slice_mIP

Number of slices used to compute the minimum intensity projection (mIP), when ismIP is enabled

Default Value: 4

Examples:

algorParam.swismwi.slice_mIP = 2;

algorParam.swismwi.slice_mIP = 4;

algorParam.swismwi.slice_mIP = 8;

algorParam.swismwi.isPositive

Save the positive (bright, e.g. paramagnetic contrast) phase-weighted SWI images

Default Value: true

Examples:

algorParam.swismwi.isPositive = true;

algorParam.swismwi.isPositive = false;

algorParam.swismwi.isNegative

Save the negative (dark, e.g. diamagnetic contrast) phase-weighted SWI images

Default Value: false

Examples:

algorParam.swismwi.isNegative = true;

algorParam.swismwi.isNegative = false;