General description

Behçet's disease is an inflammatory condition of unknown origin characterized by aphthous ulceration, perineal ulcers, ocular lesions, and skin manifestations. It is strongly associated with the HLA-B51 gene, which is positive in approximately 50% of cases.

Neuro-Behçet's disease refers to neural involvement of Behçet's disease, affecting the vasculature and brain parenchyma. Acute neuro-Behçet's disease typically presents with symptoms such as fever, headache, and neck rigidity, which may necessitate differentiation from infectious meningitis. Chronic neuro-Behçet's disease, on the other hand, is characterized by psychiatric symptoms, ataxia, and dysarthria.

Radiographic features

Acute phase

Acute neuro-Behçet's disease often affects the diencephalon to midbrain, with subsequent involvement of the pons and medulla. Additionally, the basal ganglia, and cerebral white matter may be affected, while the cerebral cortex is typically spared. Lesions typically demonstrate unilateral and asymmetric T2WI hyperintensity with contrast enhancement. Occasionally, microbleeds are observed within the lesions.

Chronic phase

Brainstem atrophy is a distinguishing feature of chronic neuro-Behçet's disease, differentiating it from the acute form of the condition.

White matter hyperintensities on T2WI and FLAIR typically originate in the corpus callosum and progressively spread into the surrounding cerebral white matter.

Spinal cord involvement

In neuro-Behçet's disease, the cervical spinal cord is typically involved, often affecting more than two vertebral segments. Imaging with T2WI frequently demonstrates a characteristic appearance known as the Bagel sign, which is marked by central hypointensity surrounded by peripheral hyperintensity. Additionally, the anterior horn of the spinal cord commonly exhibits bilateral T2WI hyperintensity, known as Motor neuron sign.