Specific Imaging Findings

Symmetric increased T2 signal in the deep gray matter is typical for Wilson disease (WD), primarily involving the putamen, followed by thalami (commonly ventrolateral), caudate, and globus pallidus. Hyperintensity may be characteristically localized to the outer rim of the putamen. Globi pallidi sometimes show very low T2 signal. In some patients the characteristic “giant panda” sign is found in the midbrain: hyperintensity throughout the tegmentum with relative sparing of red nuclei, lateral pars reticulata of the substantia nigra, and superior colliculi. Central and dorsal pons may also be affected. Dorsal pontine involvement with sparing of central tegmental tracts has been described as a second smaller panda face or “panda cub” – relatively low signal of central tegmental tracts represents the eyes and aqueduct represents the mouth. Less frequently affected are claustrum and other gray matter structures, including cortex, as well as the white matter, primarily superior and middle cerebellar peduncles. The lesions are usually of intermediate to low T1 signal intensity and do not enhance with contrast. With severe liver failure, symmetric T1 hyperintensity of globi pallidi may be present, similar to other causes of hepatic dysfunction. Generalized cerebral and cerebellar atrophy are commonly observed with WD. T2 hyperintensities frequently improve with therapy.

Pertinent Clinical Information

WD, also known as hepatolenticular degeneration, affects multiple organ systems and patients can present in strikingly diverse ways. Hepatic dysfunction is the initial manifestation in 40–50% of patients, while 40–60% present with neurologic manifestations. Neurologic symptoms usually start in the late teens, but can occur even earlier. Tremor is most frequent, followed by dysarthria, cerebellar dysfunction, dystonia, gait abnormalities, and autonomic dysfunction. Psychiatric illness is present in up to two-thirds of patients, most commonly personality changes and depression. Kayser–Fleischer rings – brown or green corneal pigmentation caused by sulfur–copper deposition – are the classic WD finding, almost invariably present in individuals with neurologic or psychiatric symptoms. Diagnosis relies on a battery of tests including slit lamp examination, serum ceruloplasmin, bound and unbound serum copper, 24-h urinary copper excretion, and neuroimaging. Liver biopsy for determination of copper content is the single most sensitive and accurate test, usually performed only when noninvasive exams are inconclusive.