[Cerebral imaging for Wilson disease]

Wilson disease is an autosomal recessive inherited copper metabolic disorder that is characterized by diminished biliary excretion of copper and a raised serum level of free copper. This leads to a toxic copper accumulation, particularly in the liver and the brain. Therefore, clinical symptoms are dominated by hepatic and extrapyramidal symptoms. Untreated Wilson disease has an unfavorable outcome. Cerebral changes are depicted most sensitively by magnetic resonance tomography. Pathological findings mainly focus on the basal ganglia, the midbrain and the brainstem. Depending on the therapy and the severity of the neurological symptoms, signal increase as well as signal decrease may be observed in T1-weighted (T1w) and T2-weighted (T2w) images and can be reversible when using an appropriate therapy. Hyperintense areas in T2-weighted images are induced by edema, gliosis, demyelinisation or cystic degeneration. Signal increase in T1-weighted images are found in patients with hepatic insufficiency and are probably due to manganese deposits. Signal decrease in T2-weighted images is probably caused by the paramagnetic effect of the copper accumulation. Furthermore, recent studies show a correlation between the clinical severity and changes in diffusion-weighted sequences. Although cross-section imaging plays a rather subordinate role in the primary diagnostics of Wilson disease, the described cerebral changes in patients with extrapyramidal disturbances should include Wilson disease in the differential. Persistent or progressive hyperintense lesions in T2-weighted images reflect therapy failure, and clinical recovery correlates to an improvement in MR images. Therefore, repeat MR imaging can be used to monitor medical therapy.