MR spectroscopy and atrophy in Gluten, Friedreich’s and SCA6 ataxias

Hadjivassiliou M, Wallis LI, Hoggard N, Grunewald RA, Griffiths PD, Wilkinson ID. MR spectroscopy and atrophy in Gluten, Friedreich’s and SCA6 ataxias. Acta Neurol Scand: 2012: 126: 138–143. © 2011 John Wiley & Sons A/S. Background – Previous work using proton MR spectroscopy (1H-MRS) of the cerebellum in the ataxias suggested that 1H-MRS abnormalities and atrophy do not necessarily occur concurrently. Aims – To investigate the spectroscopic features of different types of ataxias. Methods – Using a clinical MR system operating at 1.5T, we performed 1H-MRS with a single voxel placed over the right dentate nucleus in 22 patients with gluten ataxia (GA), six patients with Friedreich’s ataxia (FA), six patients with spinocerebellar ataxia type 6 (SCA6) and 21 healthy volunteers. Atrophy of the vermis and hemispheres on standard MRI was rated by a neuroradiologist. Any interaction between atrophy and 1H-MRS was analysed for the three groups of patients and controls. Results – Patients with GA had significant atrophy of the vermis and hemispheres as well as abnormal 1H-MRS. Patients with SCA6 had more severe overall atrophy of the vermis and hemispheres, but relatively preserved N-acetyl-aspartate/creatine (NAA/Cr). The FA group showed significant atrophy of only the superior vermis with normal 1H-MRS. Conclusions – This study suggests that 1H-MRS of the cerebellum in patients with ataxia provides information in addition to the presence of atrophy. There are significant 1H-MRS differences amongst different types of ataxia with interesting correlations between atrophy and NAA/Cr.