Differentiation between idiopathic and atypical parkinsonian syndromes using three-dimensional magnetic resonance spectroscopic imaging
- Adriane Gröger1,
- Benjamin Bender2,
- Isabel Wurster1,
- Grzegorz Lukasz Chadzynski2,
- Uwe Klose2,
- Daniela Berg1
- 1Department of Neurodegeneration, Hertie Institute for Clinical Brain Research and German Centre for Neurodegenerative Diseases (DZNE), University of Tübingen, Tübingen, Germany
- 2Department of Diagnostic and Interventional Neuroradiology, Magnetic Resonance Research Group, University Hospital Tübingen, Tübingen, Germany
- Correspondence to Dr A Gröger, Department of Neurodegeneration, Hertie Institute for Clinical Brain Research and German Centre for Neurodegenerative Diseases (DZNE), University of Tübingen, Hoppe-Seyler-Str 3, Tübingen 72076, Germany;
- Received 12 March 2012
- Revised 28 November 2012
- Accepted 18 December 2012
- Published Online First 18 January 2013
Objectives Degeneration of dopaminergic neurons in the substantia nigra (SN) pars compacta is the primary cause of idiopathic Parkinson's disease (iPD). In early stages of disease in particular, presentation of symptoms is non-specific leading to difficulties in differentiating between iPD and atypical parkinsonian syndromes (aPS). The aim of this study was to evaluate the feasibility of three-dimensional magnetic resonance spectroscopic imaging (MRSI) of the SN region for differentiation between iPD and aPS.
Methods 20 patients with iPD, 10 with aPS and 22 controls were examined on a 3 T MR scanner using three-dimensional MRSI with a voxel size of 0.252 ml and an echo time of 30 ms. Excitation volume was positioned in such a way that in each hemisphere 1 voxel defines the rostral and 1 voxel the caudal SN region. Using a fully automatic spectra evaluation, the metabolite ratios of N-acetyl aspartate/creatine (NAA/Cr) were calculated.
Results In all cases spectra with good quality were obtained. Differences in rostral to caudal NAA/Cr ratios were significant between controls and iPD patients, as well as between iPD and aPS patients (p<0.001 for both). For controls, rostral NAA/Cr was greater than caudal, whereas in iPD patients this ratio was reversed. aPS patients showed similar ratios as controls.
Conclusions Typical reversed rostral to caudal NAA/Cr ratios in iPD patients suggests that they could be linked to specific pathology of neuronal loss in the SN pars compacta. Therefore, the results suggest that MRSI may support the differential diagnosis of patients with clinically unclassifiable parkinsonian syndromes who do not yet fulfil the established clinical criteria.