Preoperative and postoperative 1H-MR spectroscopy changes in frontal deep white matter and the thalamus in idiopathic normal pressure hydrocephalus.

Abstract

BACKGROUND:

In a previous study we found significantly decreased N-acetyl aspartate (NAA) and total N-acetyl (tNA) groups in the thalamus of patients with idiopathic normal pressure hydrocephalus (iNPH) compared with healthy individuals (HI). No significant difference between the groups could be found in the frontal deep white matter (FDWM).

OBJECTIVE:

The primary aim of this study was to investigate if these metabolites in the thalamus were normalised after shunt surgery. The secondary aim was to investigate postoperative metabolic changes in FDWM.

SUBJECTS AND METHODS:

Fourteen patients with iNPH, mean age 74 years, and 15 HI, also mean age 74 years, were examined. Assessment of a motor score (MOSs) was performed before and after shunt surgery. Absolute quantitative (1)H-MR spectroscopy (1.5 T, volumes of interest 2.5-3 ml) was performed on the patients in the FDWM and in the thalamus, before and 3 months after shunt surgery, and also once on the HI. The following metabolites were analysed: tNA, NAA, total creatine, total choline (tCho), myo-inositol (mIns), glutamate and lactate concentrations. MRI volumetric calculations of the lateral ventricles were also performed.

RESULTS:

At 3 months postoperatively, we found no significant changes of tNA or NAA in the thalamus. In contrast, in the FDWM, there was a significant increase of tCho (p=0.01) and a borderline significant decrease of mIns (p=0.06). 12/14 patients were shunt responders (motor function). Median reduction of the lateral ventricle was 16%. A weak correlation between MOS and ventricular reduction was seen.

CONCLUSIONS:

Normalisation of thalamic tNA and NAA could not be detected postoperatively. The increased tCho and decreased mIns in the FDWM postoperatively might relate to clinical improvement.

• Authors: Fredrik Lundin, Anders Tisell, Göran Leijon, Olof Dahlqvist Leinhard, Leif Davidsson, Anders Grönqvist, Carsten Wikkelsø, Peter Lundberg
• Journal: Journal of neurology, neurosurgery, and psychiatry (J Neurol Neurosurg Psychiatry) Vol. 84 Issue 2 Pg. 188-93 (Feb 2013) ISSN: 1468-330X [Electronic] England
• PMID: 23134662 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Aspartic Acid
• Lactic Acid
• Glutamic Acid
• Inositol
• N-acetylaspartate
• Creatine
• Choline

Topics

• Aged
• Aged, 80 and over
• Aspartic Acid (analogs & derivatives, metabolism)
• Case-Control Studies
• Choline (metabolism)
• Creatine (metabolism)
• Female
• Frontal Lobe (metabolism)
• Functional Neuroimaging (methods)
• Glutamic Acid (metabolism)
• Humans
• Hydrocephalus, Normal Pressure (metabolism, pathology, surgery)
• Inositol (metabolism)
• Lactic Acid (metabolism)
• Lateral Ventricles (pathology)
• Magnetic Resonance Spectroscopy (methods, statistics & numerical data)
• Male
• Middle Aged
• Nerve Fibers, Myelinated (metabolism)
• Postoperative Period
• Preoperative Period
• Thalamus (metabolism)