title: Volume-selective 1H MR spectroscopy for in vivo detection of valproate in patients with epilepsy.
abstract: We performed volume-selective 1H MR spectroscopy (1H-MRS) on 12 patients on valproate monotherapy to detect valproate in vivo in the brain. We also acquired reference valproate spectra in vitro in subphysiological 15 g/l albumin solution in saline, in which valproate showed two resonance peaks at 0.7 and 1.2 ppm and a minimum detection threshold of 240 mg/l. In vivo 1H-MRS spectra in brain showed peaks between 0.6 and 1.6 ppm. Simultaneous serum valproate concentrations did not correlate with these integrated MRS peaks. On follow-up, changes in these signals also did not correlate with increasing serum valproate levels. The inconsistency of in vivo 1H-MRS signals at varying serum levels and the high detection levels in vitro suggest that valproate signals are missed in vivo because valproate is metabolised or strongly bound, presumably to brain macromolecules.
authors.affiliation: Department of Neurology, Benjamin Franklin Medical Centre, Free University of Berlin, Hindenburgdamm 30, 12200, Berlin, Germany. seyfert@ukbf.fu-berlin.de
authors.forename: S
authors.initials: S
authors.lastname: Seyfert
authors.forename: J
authors.initials: J
authors.lastname: Bernarding
authors.forename: J
authors.initials: J
authors.lastname: Braun
mesh_terms: D000328:Adult; D000927:Anticonvulsants / Q000032:analysis* / Q000627:therapeutic use; D001923:Brain Chemistry; D004827:Epilepsy / Q000175:diagnosis / Q000188:drug therapy*; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D014635:Valproic Acid / Q000032:analysis* / Q000627:therapeutic use
chemical_list: D000927:Anticonvulsants; D014635:Valproic Acid