title: Metabolic alterations in Parkinson's disease after thalamotomy, as revealed by 1H MR spectroscopy.
abstract: OBJECTIVE
  To determine, using proton magnetic resonance spectroscopy (1H MRS) whether thalamotomy in patients with Parkinson's disease gives rise to significant changes in regional brain metabolism.
  
  
  METHODS
  Fifteen patients each underwent stereotactic thalamotomy for the control of medically refractory parkinsonian tremor. Single-voxel 1H MRS was performed on a 1.5T unit using a STEAM sequence (TR/TM/TE, 2000/14/20 msec), and spectra were obtained from substantia nigra, thalamus and putamen areas, with volumes of interest of 7-8 ml, before and after thalamotomy. NAA/Cho, NAA/Cr and Cho/Cr metabolite ratios were calculated from relative peak area measurements, and any changes were recorded and assessed.
  
  
  RESULTS
  In the substantia nigra and thalamus, NAA/Cho ratios were generally low. In the substantia nigra of 80% of patients (12/15) who showed clinical improvement, decreased NAA/Cho ratios were observed in selected voxels after thalamic surgery (p < 0.05). In the thalamus of 67% of such patients (10/15), significant decreases were also noted (p < 0.05).
  
  
  CONCLUSIONS
  Our results suggest that the NAA/Cho ratio may be a valuable criterion for the evaluation of Parkinson's disease patients who show clinical improvement following surgery. By highlighting variations in this ratio, 1H MRS may help lead to a better understanding of the pathophysiologic processes occurring in those with Parkinson's disease.
authors.affiliation: Department of Biomedical Engineering, Kangnam St. Mary's Hospital College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Hyun-Man
authors.initials: HM
authors.lastname: Baik
authors.forename: Bo-Young
authors.initials: BY
authors.lastname: Choe
authors.forename: Hyoung-Koo
authors.initials: HK
authors.lastname: Lee
authors.forename: Tae-Suk
authors.initials: TS
authors.lastname: Suh
authors.forename: Byung-Chul
authors.initials: BC
authors.lastname: Son
authors.forename: Jae-Mun
authors.initials: JM
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D002794:Choline / Q000378:metabolism; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000378:metabolism* / Q000473:pathology / Q000601:surgery*; D011522:Protons; D011699:Putamen / Q000378:metabolism / Q000473:pathology; D013378:Substantia Nigra / Q000378:metabolism / Q000473:pathology; D013788:Thalamus / Q000378:metabolism* / Q000473:pathology / Q000601:surgery*
chemical_list: D011522:Protons; D001224:Aspartic Acid; C000179:N-acetylaspartate; D002794:Choline