Dear Developers and Users
Is it possible to compare the segment of a specific organ, e.g. liver, (from CT images) in two different patients?
Basically, is it reasonable to directly compare such segments (from two different patients) using the Segment Comparison module? Because the coordinate space of patients’ CT images seems to be different, it may not be correct to do this and maybe it is necessary, for example, to equalize the centers of the image space at firstly.
I investigated this by following the steps below.
1- I once compared the liver segments of two patients, without doing anything, with Segment Comparison module. Their Dice coefficient was equal to zero.
2- Once again, I first converted the segments of two patients into labelMapVolume. Then I converted both to Volume and used Center Volume option in Volume module. I re-segmented the resulting nodes with the Threshold filter in the Segment Editor module with lower and upper limits equal to 1. Finally, I calculated Dice Coefficient with Segment Comparison module. This coefficient was equal to 0.566832.
Based on this experience, I concluded that the spatial position of the two segments is dependent on the coordinate space of the initial CT images of the two patients, and this issue completely affects the value of the Dice coefficient.
Please guide me in understanding this difference.
My main question is this:
How can I calculate the similarity of two segments without this dependency?
Please guide me.