Differentiation between portal-systemic encephalopathy and neurodegenerative disorders in patients with Wilson disease: H-1 MR spectroscopy.

Abstract

To investigate the extent to which neurodegeneration and metabolic changes caused by portosystemic shunting occur in Wilson disease. Twenty-two adult patients with biochemically proved Wilson disease underwent magnetic resonance (MR) imaging, hydrogen-1 MR spectroscopy, neurologic and psychometric testing, and ultrasound evaluation of the liver. In addition, 13 age-matched adult control subjects underwent MR imaging and H-1 MR spectroscopy. For MR spectroscopy, the authors used a single-voxel technique with a repetition time of 2,000 msec and an echo time of 31 msec. The volume of interest included the right and left globi pallidus, which are the most common sites of lesions in Wilson disease. N-acetylaspartate-creatine and choline-creatine ratios were decreased in patients with Wilson disease versus control subjects (P < .001 for N-acetylaspartate-creatine ratio, P < .05 for choline-creatine ratio). Also, patients with Wilson disease and portosystemic shunting had lower myo-inositol-creatine ratios than did patients with Wilson disease and no portosystemic shunting (P < .05). Reductions in N-acetylaspartate indicate neuronal loss consistent with the neurodegenerative pattern associated with Wilson disease. In addition, H-1 MR spectroscopy shows metabolic abnormality in the brain, as decreased myoinositol, caused by portosystemic shunting.