From the University of Huddersfield in England:

One of the issues when examining examples of high value antique pocket pistols is the evaluation of the interior mechanism. Damage to the mechanism has a detrimental effect on the value of the piece, however disassembly is complicated and may cause distress to interior components. In the past X-ray has been used to avoid this, but only provides a two dimensional image which may fail to reveal aspects of interior wear or replacement components.

3D Micro CT scanning utilises a technique which enables a 360 degree examination of the interior allowing an evaluation to be made not only of internal wear and damage but also the identification of replacement parts within the mechanism which may call into question the historical authenticity of the artifact.

The video shows actual scans of several antique pistols. Music track is awful so turn your volume down: