# MRI Slice image reconstruction

I have an MRI K-Space data 320 x 320 x 256 x 8 (4D complex double) from < mridata.org > . The data represents 320 x 320 K-Space of 256 slices from 8 channels. I am trying to reconstruct images for each slice. Here is the matlab code I tried:

% Version - 1
kspacedata= kspacefile.kdata;
imRef = ifftshift(ifftn(kspacedata));
imSOS    = squeeze(sqrt(sum( abs(imRef).^2, 4))); % sum-of-squares to combine all channels

% Version - 2
kspaceSlicedata = kspacedata(:,:,100,:);
imSliceRef = ifftshift(ifftn(kspaceSlicedata));
imSliceSOS    = squeeze(sqrt(sum(abs(imSliceRef).^2, 4))); % sum-of-squares to combine all channels

% Plotting
figure;
subplot(1,2,1); imagesc(imSOS(:,:,100));title('Version - 1');axis image; colormap(gray);
subplot(1,2,2); imagesc(imSliceSOS);title('Version - 2');axis image; colormap(gray);


In Version - 1, I take inverse transform on entire kspace data and plot image data corresponding to slice 100. In Version - 2, I take kspace data corresponding to slice 100 and do inverse transform on this kspace and plot the image data. Here is the output images I obtained.

I thought both versions will reconstruct the same way. But images appeared different. How can I take kspace data corresponding to one slice and perform inverse transform to reconstruct slice image?

Thanks.