(covers information from several alternate timelines)
A neurographic scan was a detailed scan of the brain.
In the anti-time present, Beverly Crusher performed a level four neurographic scan of Jean-Luc Picard. The scan did not detect anything that might cause hallucinations or a psychogenic reaction nor signs of temporal displacement. However, the scan was detailed enough to find a small structural defect in the parietal lobe.
In the anti-time future, Data suggested to perform a complete series of neurographic scans on Picard with the equipment of the biometrics lab on the campus of Cambridge University. (TNG: "All Good Things...")