t2sGrey: Effective Transverse Relaxation

In FIACH: Retrospective Noise Control for fMRI

Description

This function returns a theoretical value for T2* based on the models presented in Yablonskiy and Haacke (1994).

Usage

t2sGrey(B0, alpha = 0.38, hct = 0.4, cbf.base = 55, chi = 1.8e-07, 
        e.base = 0.4, w0 = 267500000,r2=t2Grey(B0,TRUE),relax=TRUE)

Arguments

B0	Magnetic field strength specified in Tesla.
alpha	Power to which cbf.base is raised to estimate Cerebral Blood Volume.
hct	Hematocrit expressed as a real number between 0 and 1.
cbf.base	Cerebral Blood Flow at rest, specified in ml per mm per minute.
chi	Volume susceptibility difference between oxygenated and deoxygenated blood specified in cgs units.
e.base	1- oxygenation fraction during rest. ranging between 0 and 1
w0	Gyromagnetic ratio of the proton expressed in radians per second per tesla
r2	Transverse relaxation rate. Specified in Hz
relax	Boolean indicating whether R2* or T2* should be returned

Value

Either R2* in Hz or T2* in ms is returned

Author(s)

Tim Tierney

Examples

t2sGrey(3,relax=TRUE)
t2sGrey(3,relax=FALSE)

FIACH documentation built on May 1, 2019, 8:02 p.m.