Proton magnetic resonance spectroscopy in Steele-Richardson-Olszewski syndrome.

Proton magnetic resonance spectroscopy, localized to the lentiform nucleus, was carried out in nine patients with a clinical diagnosis of Steele-Richardson-Olszewski syndrome (SRO) and in eight healthy age-matched controls. Three of the nine SRO patients had a so-called "eye of the tiger sign" with high signal in the globus pallidus surrounded by a ring of low signal on T2 weighted magnetic resonance imaging previously only reported in Hallervorden-Spatz disease. One of these patients had pathologically proven SRO at postmortem. The SRO group showed a significant reduction in the median concentration from N-acetyl groups (median, 6.87 mM; range, 4.92-10.59 mM; p < 0.015) compared with the control group (median, 9.85 mM; range, 9.26-11.0 mM). The N-acetylaspartate concentration was significantly reduced in seven of the nine patients studied. The reduction of the N-acetylaspartate-creatine ratio from the lentiform nucleus in the SRO group may reflect neuronal loss, occurring predominantly in the globus pallidus. Proton magnetic resonance spectroscopy may be a useful, noninvasive technique to help differentiate the various parkinsonian syndromes.