The multilinear reference tissue model (MRTM) estimates the binding potential from an observed time activity curve without the need for arterial sampling. Instead, a second time activity curve must be provided from a suitable reference region where there is negligible binding.
multilinearReferenceTissueModel(
tac,
ref,
time,
tstar,
MRTM2 = TRUE,
k2prime = NULL
)Binding potential
Approximate standard error of the binding potential
Ratio of the volumes of distrubution for the tissue and reference region (assumes a one-tissue model is valid)
Approximate standard error for the ratio
Clearance rate constant from the tissue to plasma (assumes a one-tissue model is valid)
Approximate standard error for k2
Design matrix used in the linear regression
Regression coefficients
a vector corresponding to the time activity curve from the tissue (in Bq/mL).
a vector corresponding to the time activity curve from the reference region (in Bq/mL).
a vector of average frame times (in minutes).
the time (in minutes) where the linear relationship between the response and covariates may be assumed to be true.
a logical value that selects the three-parameter model (MRTM) or the two-parameter model (MRTM2), where k2prime is fixed.
the value of k2prime that has been fixed.
Brandon Whitcher bwhitcher@gmail.com
See the references.
The numeric integration required to construct the design matrix is performed
by interpolating the time activity curves, both for the tissue and reference
region, to one-second resolution and then performing the cumsum
operation on them.
Given the nonlinear relationship between binding potential and the
regression parameters, the deltamethod is used to approximate its
standard error.
Ichise, M., Ballinger, J.R., Golan, H., Vines, D., Luong, A., Tsai, S. and Kung, H.F. (1996) Noninvasive quantification of dopamine D2 receptors with iodine-123-IBF SPECT, Journal of Nuclear Medicine, 37, 513-520.
Ichise, M., Liow, J.-S., Lu, J.-Q., Takano, A., Model, K., Toyama, H., Suhara, T., Suzuki, K., Innis, R.B., Carson, R.E. (2003) Linearized reference tissue parametric imaging methods: Application to [11C]DASB positron emission tomography studies of the serotonin transporter in human brain, Journal of Cerebral Blood Flow & Metabolism, 23, 1096-1112.
cumsum, deltamethod