Identification of axonal involvement in Hallervorden-Spatz disease with magnetic resonance spectroscopy.

Hallervorden-Spatz disease is a neurodegenerative disorder associated with cysteine-iron complex accumulation typically seen as bilateral symmetrical hypointense signal changes in the medial globus pallidus on magnetic resonance imaging. We used magnetic resonance spectroscopy to identify and quantify neuronal damage in two siblings with Hallervorden-Spatz disease. The first patient presenting with a rapidly progressive extrapyramidal syndrome had markedly decreased N-acetylaspartate (NAA) to creatinine (Cr) ratios in the globus pallidi and the periatrial white matter. He also had increased myoinositol (mI) to creatinine (Cr) ratios implying glial proliferation in the affected regions. However the second patient who had the initial presentation of disease had normal NAA/Cr and mI/Cr ratios. These findings indicate that the quantification of NAA:Cr and mI:Cr ratios might be used to predict the extent of neuronal axonal loss and glial proliferation in patients with Hallervorden-Spatz disease respectively.