Reply:
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* H. Prosch
* N. Grois
* D. Prayer

Thank you for your interest in our article1 and for sharing your interesting case. The proton MR spectra fit well with that of another patient with neurodegenerative Langerhans cell histiocytosis (ND-LCH) previously reported.2 Decreased *N*-acetylaspartate peak accompanied by increased choline in the area of cerebellar signal intensity alterations supports the concept of a neurodegenerative process. Further studies are necessary to evaluate the sensitivity and specificity of 1H-MR spectroscopy in ND-LCH.

## References

1.  Prosch H, Grois N, Wnorowski M, et al. **Long-term MR imaging course of neurodegenerative Langerhans cell histiocytosis.** AJNR Am J Neuroradiol 2007;28:1022–28
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czo5OiIyOC82LzEwMjIiO3M6NDoiYXRvbSI7czoxOToiL2FqbnIvMjkvNC9lMTUuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

2.  Steiner M, Prayer D, Asenbaum S, et al. **Modern imaging methods for the assessment of Langerhans’ cell histiocytosis-associated neurodegenerative syndrome: case report.** J Child Neurol 2005;20:253–57
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NToic3BqY24iO3M6NToicmVzaWQiO3M6ODoiMjAvMy8yNTMiO3M6NDoiYXRvbSI7czoxOToiL2FqbnIvMjkvNC9lMTUuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

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