DTI MRI (Diffusion Tensor Imaging) does not show severed brain connections. It shows abnormal fluid flow that indicates improper function of brain cells.

How old were you when you suffered your TBI ?
Why would you expect to have a titanium plate or polymer plate ?

Do you have a specific symptom you are trying to treat ?

In the US, most medical records are not kept past 7 years unless they get digitized (scanned) and stored electronically. 20 years ago, not many hospitals were digitizing records so physical (paper or film) records would be destroyed unless there was an ongoing need.