DICOM, PIXEL VALUE, VISUALIZATION

i masked a specific pixel range( suppose 1800 to 2000) in 381 heart dicom files and after viewing the masked pixed on volumeViewer App it gives me structure in below attached picture. Now i want to see on what area all the masked images are superimposing on the original heart ct scans(before masking)? what can I do for that?

and if I want to remove the bones to just see the heart how can i process for that?

[KALYAN ACHARJYA]

Sorry, not Getting the question can you simply more, is it asking for XOR logical opration/ or other logical operation between two images?