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J Neurol Neurosurg Psychiatry 82:772-778 doi:10.1136/jnnp.2010.223529
  • Research paper

Reduced thalamic N-acetylaspartate in idiopathic normal pressure hydrocephalus: a controlled 1H-magnetic resonance spectroscopy study of frontal deep white matter and the thalamus using absolute quantification

  1. G Leijon1
  1. 1Department of Clinical and Experimental Medicine, Division of Neuroscience, Linköping University, Linköping, Sweden
  2. 2Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden
  3. 3Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
  4. 4Department of Medical and Health Sciences, Division of Radiation Physics, Linköping University, Linköping, Sweden
  5. 5Department of Radiation Physics, CKOC, University Hospital of Linköping, Linköping, Sweden
  6. 6Department of Radiology, University Hospital of Linköping, Linköping, Sweden
  1. Correspondence to Dr Fredrik Lundin, Division of Neuroscience, University of Linköping, S-581 85 Linköping, Sweden; fredrik.lundin{at}lio.se
  • Received 16 July 2010
  • Revised 1 October 2010
  • Accepted 1 November 2010
  • Published Online First 8 January 2011

Abstract

Introduction Patients with idiopathic normal pressure hydrocephalus (INPH) frequently have a reduction in cerebral blood flow in the subcortical frontal lobe/basal ganglia/thalamic areas. With magnetic resonance spectroscopy, the metabolism in the brain can be examined. The aim of this study was to investigate if there was a compromised metabolism in the thalamus and in the subcortical frontal areas in INPH patients. This was done by measuring total creatine, myo-inositol, total choline, N-acetylaspartate (NAA), total N-acetylaspartate (tNA), glutamate and lactate levels. A comparison was made with healthy individuals (HI).

Subjects and methods 16 patients (nine males, seven females, mean age 74 years, range 49–83) diagnosed as INPH and 15 HI (nine males, six females, mean age 74 years, range 62–89) were examined. 1H magnetic resonance spectroscopy (1.5 T, point-resolved spectroscopy, echo time/relaxation time 30/3000 ms, volume of interest 2.5–3 ml) was performed in frontal deep white matter and in the thalamus. Absolute quantification with internal water as a reference was used.

Results INPH patients had lower NAA (p=0.02) and lower tNA (p=0.05) concentrations in the thalamus compared with HI. NAA and tNA in the frontal deep white matter did not differ between patients and HI. The absolute metabolic concentrations of total creatine, myo-inositol total choline, tNA, lactate and Cr ratios in frontal deep white matter and in the thalamus were similar in INPH patients and HI.

Conclusion Reduced thalamic NAA and tNA in INPH patients suggest a compromised metabolic neuronal function in these regions. Thus, the thalamus might have an important role in the pathogenesis of INPH.

Footnotes

  • FL and AT contributed equally.

  • Funding Financial support from the National Research Council (VR/NT), University Hospital Research funds, Center for Medical Image Science and Visualization and the University of Linköping.

  • Competing interests None.

  • Patient consent Obtained.

  • Ethics approval Ethics approval was provided by the Regional Ethical Review Board in Linköping, Sweden.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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