`bcurve` computes the right-hand-side of equation
11, that is,

In the early stages of the development of RCBF,

- 1.
- Input and output arguments:
function integral = b_curve ... (args, shifted_g_even, ts_even, A, fstart, flengths)

The output argument`integral`is just the values of equation 18 after frame-by-frame integration, i.e. there is one number for each frame.The input arguments are = 0=

- <879>>=-0.25in
0
=
- args
- a three element vector containing ,
,
and
from equation . Keep in mind in the
following code that
`args(1)`is ,`args(1)`is , and`args(1)`is . - g_even
- the blood data resampled at an evenly-spaced time domain, and possibly shifted by some delay factor . We are not interested here in what that value of is, however.
- ts_even
- the evenly-spaced time domain at which
`g_even`is sampled. - A
- the PET activity, averaged over gray matter, for the current
slice. (This isn't actually used in
`b_curve`, but the argument is still here for historical reasons and to make calls to`b_curve`and`fit_b_curve`look the same.) - fstart
- the frame start times.
- flengths
- the frame lengths.
- 2.
- Evaluate the first term of the integrand in equation 18.
expthing = exp(-args(2)*ts_even); c = nconv(shifted_g_even,expthing,ts_even(2)-ts_even(1)); c = c (1:length(ts_even)); i1 = args(1)*c; % alpha * (convolution)

- 3.
- Evaluate the second term of the integrand, and the two terms
together to get the integrand,
`i`.i2 = args(3)*shifted_g_even; % gamma * g(t - delta) i = i1+i2;

- 4.
- Perform the frame-by-frame integration.
integral = nframeint (ts_even, i, fstart, flengths);

- 5.
- Clean up any NaN's that have cropped up by setting them to zero.
Also, truncate the function to whatever length
`A`is.nuke = find (isnan (integral)); integral (nuke) = zeros (size (nuke)); integral = integral (1:length(A));

`<:`<879>>

**Next:**Using the rCBF Package**Up:**Annotated Program Listings**Previous:**FINDINTCONVO Mark Wolforth <wolforth@bic.mni.mcgill.ca>

Greg Ward <greg@bic.mni.mcgill.ca>

Sean Marrett <sean@bic.mni.mcgill.ca>