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Keywords:

  • Phosphorus spectroscopy;
  • Magnetic resonance imaging;
  • Neurometabolism;
  • Energetics;
  • Malformations of cortical development;
  • Epilepsy

Summary

Purpose:  The aim of this study was to evaluate phospholipid metabolism in patients with malformations of cortical development (MCDs).

Methods:  Thirty-seven patients with MCDs and 31 control subjects were studied using three-dimensional phosphorus magnetic resonance spectroscopy (31P-MRS) at 3.0 T. The voxels in the lesions and in the frontoparietal cortex of the control subjects were compared (the effective volumes were 12.5 cm3). Robust quantification methods were applied to fit the time-domain data to the following resonances: phosphoethanolamine (PE); phosphocholine (PC); inorganic phosphate (Pi); glycerophosphoethanolamine (GPE); glycerophosphocholine (GPC); phosphocreatine (PCr); and α-, β-, and γ-adenosine triphosphate (ATP). We also estimated the total ATP (ATPt = α-+β-+γ-ATP), phosphodiesters (PDE = GPC+GPE), phosphomonoesters (PME = PE+PC), and the PME/PDE, PCr/ATPt and PCr/Pi ratios. The magnesium (Mg2+) levels and pH values were calculated based on PCr, Pi, and β-ATP chemical shifts.

Key Findings:  Compared to controls and assuming that a p-value < 0.05 indicates statistical significance, the patients with MCDs exhibited significantly lower pH values and higher Mg2+ levels. In addition, the patients with MCDs had lower GPC and PDE and an increased PME/PDE ratio.

Significance:  Mg2+ and pH are important in the regulation of bioenergetics and are involved in many electrical activity pathways in the brain. Our data support the idea that neurometabolic impairments occur during seizure onset and propagation. The GPC, PDE, and PME/PDE abnormalities also demonstrate that there are membrane turnover disturbances in patients with MCDs.