Diffusion weighted magnetic resonance imaging in Neuro-Behçet's disease

T2 weighted image (A) and apparent diffusion coefficient map (B) obtained 3 days after onset show T2 hyperintensity and increased diffusion involving a basal ganglion on the right side. Follow up images (C and D) obtained 1 year later show considerable resolution of previous T2 and diffusion abnormalities but basal ganglia atrophy. Neurological involvement is one of the most devastating manifestations of Behcet's disease.1 However, the pathogenic mechanism for CNS lesions in patients with neuro-Behcet's disease is unclear. Although vasculitis is usually considered to be the central pathological feature in Behcet's disease, a vasculitic process was not usually demonstrated in the CNS.2 Diffusion weighted imaging can detect changes in water diffusion associated with cellular dysfunction. It has been well documented that acute infarction related to cytotoxic oedema is characterised by a marked decrease in diffusion, and also that increased interstitial water related to vasogenic oedema shows increased diffusion.3 Conventional MRI cannot distinguish between these different types of oedema. We report on a patient with neuro-Behcet's disease with a significantly reversible T2 signal and diffusion abnormalities in CNS lesions. A 54 year old Asian man was admitted with dysarthria and left hemiparesis, which evolved over a period of 2 days and was associated with gradual mental …