What is the role of brain MRI in the workup of Wilson disease?

Updated: Feb 14, 2019
  • Author: Richard K Gilroy, MBBS, FRACP; Chief Editor: Praveen K Roy, MD, AGAF  more...
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Answer

MRI of the brain appears to be more sensitive than CT scanning in detecting early lesions of Wilson disease. MRI studies have identified focal abnormalities in the white matter, pons, and deep cerebellar nuclei. These lesions, measuring 3-15 mm in diameter, are typically bilateral, appearing with low signal intensity on T1-weighted images and with high signal intensity on T2-weighted images, representing cell loss and gliosis. Other studies describe decreased signal intensity in the putamen and other parts of the basal ganglia, which may represent either copper or iron ferritin deposition.

A characteristic "face of the giant panda" sign has been described, formed by high signal intensity in the tegmentum (except for the red nucleus), preserved signal intensity of the lateral portion of the pars reticulata of the substantia nigra, and hypointensity of the superior colliculus.

Results from a study by Tarnacka et al indicated that relative to the thalamus, the basal ganglia are more sensitive to ongoing degenerative changes and portal-systemic encephalopathy in Wilson disease. The authors used proton magnetic resonance spectroscopy (MRS) in 37 patients with newly diagnosed Wilson disease to identify the pathomechanism of the disease's cerebral pathology, specifically looking at the globus pallidus and thalamus to assess cerebral metabolic changes in myoinositol, choline, creatine, N-acetyl-aspartate, lipid, glutamine, and glutamate levels and ratios. [19]

The investigators speculated that N-acetyl-aspartate/creatine ratio reductions seen in hepatically and neurologically impaired patients in the study may have indicated an association between neurodegeneration and all presentations of Wilson disease. In addition, they suggested that observed decreases in myoinositol and choline and an increase in neurologic glutamate may have been due to portosystemic shunting. [19]


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