My dad's a radiologist, so access to scans isn't an issue, but the sticking point would be knowing what's normal and what's not.

That looks like a bog-standard USB cable, but Apple's Lightning and USB-C cables are far more complicated, with actual chips onboard.

https://www.chipworks.com/blog/systems-analysis-apple-lightn...

I don't think there's much possibility of me vetting one of these sorts of third-party cable based on an x-ray, or even a physical teardown.