partialVolumeCorrection: Perform partial volume correction for ASL images.

In neuroconductor/ANTsR: ANTs in R: Quantification Tools for Biomedical 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(img, img.gm, img.wm, mask = NULL, proportion = 0.4)

Arguments

img	Low-resolution image to be corrected. All input images can be either of type antsImage or numeric vectors (if numeric vectors, the mask is ignored).
img.gm	Gray matter probability image for partial volume correction.
img.wm	White matter probability image for partial volume correction.
mask	Brain mask for image.
proportion	Ratio of activity for white matter to gray matter. Assumed to be 0.4.

Value

Returns partial volume corrected antsImage.

Author(s)

Kandel BM

References

Method: Pattern of cerebral hypoperfusion in Alzheimer disease and mild cognitive impairment measured with arterial spin-labeling MR imaging: initial experience. Johnson NA, Jahng GH, Weiner MW, Miller BL, Chui HC, Jagust WJ, Gorno-Tempini ML, Schuff N. Radiology 2005.

Ratio of GM to WM activity: Quantitative magnetic resonance imaging of human brain perfusion at 1.5 T using steady-state inversion of arterial water. Roberts DA, Detre JA, Bolinger L, Insko EK, Leigh JS Jr. PNAS 1994.

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)

neuroconductor/ANTsR documentation built on Oct. 11, 2020, 8:14 a.m.