imgflowd - tpcclib 0.8.0 © 2023 by Turku PET Centre

Estimation of rate constants K1 (perfusion), k2 and Va from dynamic
radiowater PET image in ECAT 6.3, ECAT 7.x, NIfTI-1, or Analyze 7.5 file
format using. The two-compartment model equations
  dCt(t)/dt = K1*Ca(t) - k2*Ct(t)
  Croi(t) = Va*Ca(t) + Ct(t)
are linearized (1) into equation
  Croi(t) = Va*Ca(t) + (K1+Va*k2)*Integral[Ca(t)] - k2*Integral[Croi(t)]
from which the model parameters are solved using Lawson-Hanson non-negative
least squares (NNLS) method (2).
Arterial blood curve (BTAC) and dynamic PET image must be corrected for physical decay.
BTAC sample times must be in seconds.
Since time delay varies inside PET image, this program requires a delay map
which contains the time delay for each image pixel.
Usage: imgflowd [Options] btacfile imgfile delayfile flowfile
 -end=<Fit end time (sec)>
     Use data from 0 to end time; by default, all of it.
     Parametric k2 image is saved; in some situations perfusion calculation
     from k2 can be more accurate than the default assumption of f=K1.
     Perfusion can be calculated from k2 using equation f=k2*pH2O, where
     pH2O is the physiological partition coefficient of water in tissue.
 -Va=<filename> | -Va=0
     Parametric Va image is saved, or set Va to 0 if image is pre-corrected
     for arterial blood volume; by default Va is fitted.
 -max=<Max value>
     Upper limit for blood flow (K1) values.
     Pixels with negative K1 estimates are set to zero.
 -h, --help
     Display usage information on standard output and exit.
 -v, --version
     Display version and compile information on standard output and exit.
 -d[n], --debug[=n], --verbose[=n]
     Set the level (n) of debugging messages and listings.
 -q, --quiet
     Suppress displaying normal results on standard output.
 -s, --silent
     Suppress displaying anything except errors.
The units of pixel values in the blood flow (K1) image is
(mL blood)/((mL tissue) * min), in k2 image 1/min, and
in Va image (mL blood/mL tissue).
1. Blomqvist G. On the construction of functional maps in positron
   emission tomography. J Cereb Blood Flow Metab. 1984;4:629-632.
2. Lawson CL & Hanson RJ. Solving least squares problems.
   Prentice-Hall, 1974.
See also: imgdelay, imgflowm, imgbfh2o, imgcbv
Keywords: image, modelling, perfusion, blood flow, radiowater, NNLS