Role of 3D FLAIR in Demonstration of Peripheral Lesions of Brainstem and Cranial Neuropathies

Aim: We present a pictorial review of 3D FLAIR images depicting its importance in demonstrating the peripheral lesions of brainstem particularly in relation to attachment of cranial nerves and cranial neuropathies and particularly in context of patients with multiple sclerosis (MS).

Discussion: T2 axials and routine 2D FLAIR have drawbacks in depicting the lesions on the peripheral aspects of brainstem. Such lesions are commonly found in MS. The revised McDonald’s criteria (2010) put equal emphasis on periventricular, juxtacortical, infratentorial and cord lesions. Detection of peripheral lesions thus play important role in fulfilling the criteria of dissemination in space and also provide anatomic correlate in several cranial nerve palsies. In clinically isolated syndromes, demonstration of lesions at the site of affected cranial nerves increase diagnostic confidence and exclude other potential disease processes. Ability to show signal changes at cranial nerve attachment can also potentially prevent a false attribution of symptoms to neurovascular compression.

Conclusion: We propose that 3D FLAIR sequence is extremely useful in detecting abnormalities on the surface of brainstem and cranial nerve attachments and should be performed in all patients of MS and cranial nerve palsies.