I want to do segmentation of Brain MRI.

I remove the skull and tissue from Brain MRI using morphological operation. After that I tried that code for segmentation

bw = im2bw(binaryImage,0.7);
label = bwlabel(binaryImage);

stats = regionprops(label, 'Solidity' ,'Area');
density= [stats.Solidity];
area=[stats.Area];
high_dense_area =density > 0.5;
max_area = max(area(high_dense_area));
tumor_label= find(area == max_area);
tumor = ismember(label, tumor_label);
biggest = find(area==max(area));
subplot(2,3,6);
imshow(tumor,[]);
title('Tumor Area');

But this code detect tumor in few MR images. Sometimes it does not give the exact tumor region. how can i fix this code?