imgbfh2o - tpcclib 0.8.0 © 2023 by Turku PET Centre
Estimation of rate constants K1, k2 and Va from dynamic PET image in
ECAT 6.3, ECAT 7.x, NIfTI-1, or Analyze 7.5 file format using
one-tissue compartment model (1), solved using the basis function
approach (2, 3).
When applied to dynamic [O-15]H2O studies, the resulting K1 image
equals perfusion (blood flow) image. K1 image can be divided by tissue
density (g/mL) (option -density) and multiplied by 100 (option -dL)
to achieve the blood flow image in units (mL blood)/((100 g tissue) * min).
When applied to dynamic [O-15]O2 brain studies, the resulting K1 image
can be converted to oxygen consumption image by multiplying it by
arterial oxygen concentration (4) (mL O2 / dL blood) to get the
parametric image in units mL O2 / ((100 ml tissue) * min).
The model assumptions hold only when oxygen consumption is 1-6.7
mL O2/(100g * min) and fit time is set to 300 s or less (4).
Arterial blood TAC must be corrected for decay and delay, with sample times
in seconds. Dynamic PET image must be corrected for decay. Fit time must
be given in seconds.
Usage: imgbfh2o [Options] btacfile imgfile fittime flowfile
-mL or -dL
Units in flow and Va images will be given per mL or per dL,
respectively. By default, units are per mL.
With option -density the flow is calculated per gram or 100g tissue.
Tissue density can be changed from the default 1.04 g/mL.
Parametric K1/k2 (Vd, apparent p) image is saved.
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.
Parametric Va image is saved.
Set -Va=0, if Va=0 is assumed (pre-corrected); otherwise Va is fitted.
Weighted sum-of-squares are written in specified image file.
Pixels with AUC less than (threshold/100 x input AUC) are set to zero;
default is 0%
-k2min=<Min k2> and -k2max=<Max k2>
Enter the minimum and maximum k2 in units 1/min, applying to decay
-fmin=<Min K1> and -fmax=<Max K1>
Enter the minimum and maximum perfusion value; defaults are
0.005 and 4.0 mL/(mL*min), respectively.
-pmin=<Min p> and -pmax=<pmax>
Enter the minimum and maximum value for apparent partition coefficient
for water; defaults are 0.3 and 1.0 mL/mL, respectively.
Set number of basis functions; default is 500, minimum 100.
Basis function curves are written in specified file.
Pixels with their k2 in its min or max value (calculated from min and
max K1 and p values) in the specified imagefile with values 1 and 2,
respectively, others with value 0.
Display usage information on standard output and exit.
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.
Suppress displaying normal results on standard output.
Suppress displaying anything except errors.
Example 1. Calculation of perfusion and arterial blood volume image,
stopping fit at 180 s:
imgbfh2o -Va=s2345va.img s2345abfit.kbq s2345dy1.v 180 s2345flow.v
By default, the units of pixel values in the blood flow (K1) image is
(mL blood)/((mL tissue) * min), in Vd image (mL blood)/(mL tissue),
in k2 image 1/min, and in Va image (mL blood/mL tissue),
but the blood flow and Va units can be changed with above listed options.
1. Lammertsma AA, Jones T. J Cereb Blood Flow Metab. 1983;3:416-424.
2. Koeppe RA et al. J Cereb Blood Flow metab. 1985;5:224-234.
3. Boellaard R et al. Mol Imaging Biol. 2005;7:273-285.
4. Ohta S, et al. J Cereb Blood Flow Metab. 1992;12:179-192.
See also: bfmh2o, imgflow, arlkup, fit_h2o, imgunit, fitdelay, imgcbv
Keywords: image, modelling, perfusion, radiowater, basis function method