Differentiation of SCA2 from MSA-C using proton magnetic resonance spectroscopic imaging.
OBJECTIVE
To assess and compare biochemical and volumetric features of the cerebellum in patients with spinocerebellar ataxia type 2 (SCA2) and patients with the cerebellar variant of multiple system atrophy (MSA-C).


METHODS
Nine genetically assigned SCA2 patients and six MSA-C patients who met the clinical criteria of MSA-C underwent a clinical and neuroradiological workup with respect to cerebellar features. The MR protocol consisted of a sagittal T1-weighted three-dimensional fast low-angle shot (3D FLASH) sequence and a transversal T2- and spin-density-weighted turbo spin-echo sequence. The proton magnetic resonance spectroscopic imaging ((1)H-MRSI) protocol consisted of two chemical shift imaging (CSI) sequences (echo time (TE) = 20 and 135 msec).


RESULTS
Both short- and long-TE MR spectroscopy (MRS) images showed significant decreases in values for N-acetylaspartate to creatine (NAA/Cr), and choline to creatine (Cho/Cr) ratios in MSA-C and SCA2 compared to normal controls, though there was no difference between the two patient groups. In contrast, distinct cerebellar lactate (Lac) peaks were detected in seven SCA2 patients, and small peaks were detected in two. However, we did not detect any definite Lac peak in MSA-C or control subjects.


CONCLUSIONS
MRSI revealed Lac pathology in SCA2 but not in MSA-C. Whether this indicates distinct pathogenetic mechanisms of cerebellar degeneration remains to be established.
Boesch
Sylvia M
SM
Department of Neurology, Medical University Innsbruck, Innsbruck, Austria. Sylvia.Boesch@uibk.ac.at
Wolf
Christian
C
Seppi
Klaus
K
Felber
Stephan
S
Wenning
Gregor K
GK
Schocke
Michael
M
D000328:Adult; D017668:Age of Onset; D000368:Aged; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D002531:Cerebellum / Q000473:pathology; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D019344:Lactic Acid / Q000378:metabolism; D008279:Magnetic Resonance Imaging / Q000379:methods; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D019578:Multiple System Atrophy / Q000175:diagnosis* / Q000378:metabolism; D012016:Reference Values; D012720:Severity of Illness Index; D020754:Spinocerebellar Ataxias / Q000175:diagnosis* / Q000378:metabolism; D013997:Time Factors
D001224:Aspartic Acid; D019344:Lactic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline