Anyone know what is wrong with my T2* calculations?

%Variable definitions:
Masks = niftiread("Gated_Image_TE1_1.nii.gz");

%T2* Calculations, lets see if this works
fitfunc = cftool;

%Echo times matrix
x = [0.086883, 0.15, 0.3, 0.7 ];

%Images = matrix;

    Images = zeros(128,128,128,4);
    Images(:,:,:,1) = niftiread('Original_Gated_Image_TE1_1.nii.gz'); 
    Images(:,:,:,2) = niftiread('Original_Gated_Image_TE2_1.nii.gz'); 
    Images(:,:,:,3) = niftiread('Original_Gated_Image_TE3_1.nii.gz'); 
    Images(:,:,:,4) = niftiread('Original_Gated_Image_TE4_1.nii.gz'); 
   Images = Images/max(Images(:));
    %%
tic
A = zeros(size(Masks));
B = zeros(size(Masks));
C = zeros(size(Masks));
D = zeros(size(Masks));
SB=0;
%f0 = fitoptions('Origins',[0,0]);
for i = 1:128
    for j = 1:128
        parfor k = 1:128
            if Masks(i,j,k) == 1
                try
                    y = squeeze(Images(i,j,k,:));
                    %myfit = fit(x',y,'exp2','StartPoint',[0,0,0,0]);
                    myfit = fit(x',y, 'a*exp(-x/b)+c', 'StartPoint', [1,0.2,0.001],'UpperLimit',[10000,2,.05],'LowerLimit',[0,0,-Inf]);
                    A(i,j,k) = myfit.a;
                    B(i,j,k) = myfit.b;
                    C(i,j,k) = myfit.c;
                %D(i,j,k) = myfit.d;
                catch
                    %B(i,j,k) = -10;
                    %disp('Something Broke');
                    SB=SB+1;
                end

            end
        end
    end
end
toc

So when I try to run the mask (Gated_ImageTE1_1.nii.gz) over the origianl scan ('Original_Gated_Image_TE1_1.nii.gz') nothing comes back. When I unkill the catch functions the entire thing just ends up having a value of -10 where the mask should be. So I am unsure as to what is happening and why. If anyone could let me know what is happening that would be greatly appreciated! Thanks in advance.

Answer 1

[Catalytic]

The problem with try...catch is that if you have any coding errors in the try block, it will never get executed. Here, you are using parameter names 'UpperLimit' and 'LowerLimit', which do not exist.

It would be much better to request an exitflag from FIT, instead of using try/catch -

[myfit,~,output]=fit( ___ )
if output.exitflag<=0
    continue
end

[William]

This helped! Sorry it took me a while to get back to you. Forgot to respond and mark helped