Inflammated nerves show on an mri?i get pain nerve under my eyebrow, my neurologist didn't put me a diagnostic put he thinks it could be trochleitis.

Depends: severe inflammation can show on MRI whereas, subtle inflammation may not. Can you describe your nerve pain a bit better?

No imaging for pain!: No existing imaging technologies show nerve transmission, much less sensations of pain. The closest to something like this: PET brain imaging for relative metabolic activity of different brain regions, yet this is still extremely crude reflecting complex activity of hundreds of thousands to millions of neurons as groups. The vehicle we are driving is far more complex than any medical technologies.

Yes: Inflammation in the trochlear area would likely show up on MRI. That being said, trochleitis is a clinical diagnosis and a common cause of one sided pain and swelling in the eyebrow area. Try appropriate therapy for several weeks (probably steroids and possibly acupuncture) and see if it resolves.

MRI Optional: Although brain MRI's can show trochlear nerves as potentially inflamed your neurologist believes that the problem is out in the periphery due to your symptoms. Brain imaging or even orbital imaging itself may not reveal such inflammation especially if minor. Remember, in the 21st-century of managed care and cost-effective medicine the catchphrase is: "Go Clinical or Go Home. "

Sinus: I would make sure you have ruled out more common etiologies like sinusitis. Eval by an ENT would be worthwhile.