Instead of having 76 separate image matrices, you should hold all the slices in an MxNxP array. If A is this array, then you can extract slices along whatever axis you want by indexing
A(:,:,i); %axial
A(:,i,:); %sagittal/coronal
A(i,:,:); %coronal/sagittal
You can also use griddedInterpolant() to interpolate oblique slices.
