FIACH (version 0.1.2)

t2sGrey: Effective Transverse Relaxation

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

Examples

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