Unless they are all lying:

AI Overview

The recent MRI Donald Trump underwent in October was not a brain MRI, according to a memo released by the White House physician. The scan was for his cardiovascular and abdominal systems.

When asked by reporters about the MRI, Trump stated he had "no idea" what part of his body was scanned but insisted "It wasn't the brain because I took a cognitive test and I aced it".

The memo from Dr. Sean Barbabella, the physician to the President, detailed that the "advanced imaging" was performed as a preventative measure considered standard for men in his age group, to evaluate cardiovascular and abdominal health. The results of these scans were described as "perfectly normal".