partialVolumeCorrection¶

purpose:

Perform partial volume correction for ASL images.

description:

This function performs a partial volume correction for ASL images by dividing the observed CBF by the gray matter and white matter probabilities, as described in Johnson et al., Radiology 2005: CBF_corrected = CBF_observed / (GM_prob + 0.4 * WM_prob)

usage:

partialVolumeCorrection(image, image.gm, image.wm, mask=NULL, proportion=0.4)

examples:

activity.gm <- 10

activity.wm <- activity.gm * 0.4

percent.gm <- matrix(seq(0.1, 1, by = 0.1), nrow = 2)

percent.wm <- -percent.gm + 1

activity.obs <- percent.gm * rnorm(n = length(percent.gm), mean = activity.gm,
    sd = 5) +
rnorm(n = length(percent.wm), mean = activity.wm, sd = 5)

activity.corrected <- partialVolumeCorrection(activity.obs, percent.gm, percent.wm)