Seven-Tesla proton magnetic resonance spectroscopic imaging in adult X-linked adrenoleukodystrophy.

[adrenomyeloneuropathy]

Adults with X-linked adrenoleukodystrophy (X-ALD ) remain at risk for progressive neurological deterioration . Phenotypes vary in their pathology , ranging from axonal degeneration to inflammatory demyelination . The severity of symptoms is poorly explained by conventional imaging .To test the hypothesis that neurochemistry in normal-appearing brains differs in adult phenotypes of X-ALD and that neurochemical changes correlate with the severity of symptoms .Using a 7 -Tesla scanner , we performed structural and proton magnetic resonance spectroscopic imaging in 13 adult patients with X-ALD : 4 patients with adult cerebral ALD , 5 patients with adrenomyeloneuropathy (AMN ), and 4 female heterozygotes . Nine healthy controls were included .Among adult X-ALD phenotypes , the myo-inositol to creatine ratio was 46 % higher and the choline to creatine ratio was 21 % higher in normal-appearing white matter of those with adult cerebral ALD compared with those with AMN (P < .05 ). Both N-acetylaspartate to creatine (P = .03 ) and glutamate to creatine (P = .04 ) ratios were lower in AMN patients than in controls . There were no significant differences between patients with AMN and female heterozygotes . In the cortex , patients with adult cerebral ALD had lower N-acetylaspartate to creatine ratios compared with female heterozygotes and controls (P = .02 ). The global myo-inositol to creatine ratio demonstrated a significant association with Expanded Disability Status Scale score (Spearman rho = 0 .66 , P = .04 ).Seven -Tesla proton magnetic resonance spectroscopic imaging reveals differences in the neurochemistry of adult cerebral ALD but can not distinguish AMN patients from female heterozygotes . Myo-inositol to creatine ratio correlates with the severity of the symptoms and may be a meaningful biomarker in adult X-ALD .