What are the typical MRI findings of the brain and spine in a case of Guillain-Barré Syndrome (GBS)?

MRI Findings in Guillain-Barré Syndrome (GBS)

MRI is not part of routine diagnostic evaluation for GBS but can reveal characteristic nerve root enhancement on gadolinium-enhanced imaging, which is a sensitive but nonspecific feature that can support the diagnosis, especially in young children where clinical and electrophysiological assessment may be challenging. 1

Brain MRI Findings

• Brain MRI is typically normal in classical GBS 2
• May be useful to exclude differential diagnoses such as brainstem infection, stroke, or other neurological conditions 1
• No specific brain abnormalities are characteristic of GBS 2, 3

Spine MRI Findings

• Nerve root enhancement is the most characteristic finding:

  • Thickening and enhancement of intrathecal spinal nerve roots and cauda equina on gadolinium-enhanced T1-weighted images 4, 5, 6
  • Enhancement patterns may vary:
    • Enhancement of both anterior and posterior spinal nerve roots 6
    • Enhancement of only anterior spinal nerve roots (strongly suggestive of GBS) 6
  • Enhancement is most commonly seen in the thoracolumbar region 5

• High sensitivity of nerve root enhancement:

  • Present in up to 92-100% of pediatric GBS cases 5
  • Enhancement correlates with inflammatory infiltration and breakdown of the blood-nerve barrier 4

• Follow-up imaging may show:

  • Diminished thickening and enhancement of spinal nerve roots with clinical improvement 6

Clinical Utility of MRI in GBS

• Primary utility is to exclude differential diagnoses rather than confirm GBS 1

• Particularly helpful in:

  • Young children where clinical and electrophysiological assessment can be challenging 1
  • Atypical presentations of GBS 2, 3
  • Distinguishing GBS from acute flaccid myelitis in children 1

• Differential diagnoses that can be excluded with MRI include:

  • Brainstem infection or stroke 1
  • Spinal cord or anterior horn cell inflammation 1
  • Nerve root compression 1
  • Leptomeningeal malignancy 1

Important Caveats

• Nerve root enhancement is nonspecific and can be seen in other conditions:

  • Neoplastic processes affecting nerve roots 6
  • Other inflammatory conditions 6
  • A minority of cases of acute flaccid myelitis 1

• MRI findings should always be interpreted in conjunction with:

  • Clinical presentation (progressive symmetric weakness with areflexia) 2, 3, 7
  • CSF analysis (albumino-cytological dissociation) 2, 7
  • Electrodiagnostic studies 1, 2

• Timing of MRI may affect sensitivity:

  • Enhancement may not be present very early in the disease course 5
  • Repeat imaging may be necessary if initial MRI is negative but clinical suspicion remains high 5

Protocol Recommendations

• Spine MRI should include:
  • T1-weighted sequences with and without gadolinium enhancement 1
  • T2-weighted sequences in sagittal and axial planes 1
  • Fat-suppressed T2-weighted sequences (STIR) 1
  • High-resolution steady-state or equivalent heavily T2-weighted 3D sequence 1