K. Johannik et al., LOCALIZED BRAIN PROTON NMR-SPECTROSCOPY IN YOUNG-ADULT PHENYLKETONURIA PATIENTS, Magnetic resonance in medicine, 31(1), 1994, pp. 53-57
Localized proton magnetic resonance spectroscopy with short echo time
(TE= 20 ms) was used to investigate biochemical changes in the cerebra
l white matter of 20 young adult patients (median 19 years) with pheny
lketonuria (PKU). Results were compared with those of a group of 12 ag
e-matched healthy volunteers (median 25 years). Concentrations of N-ac
etyl-aspartate (NAA) and choline (Cho) relative to creatine (Cr) were
unchanged. However, concentrations of inositol (Ins) relative to creat
ine were found to be significantly lower (P < 0.001) in the PKU patien
ts (0.30 +/- 0.09 versus 0.57 +/- 0.17). Individual inositol concentra
tions did not correlate with age, diet, serum phenylalanine (Phe) leve
ls or extent of pathological regions in the T-2-weighted images. The l
ack of correlation with individual data suggests that the decreased in
ositol concentration could be related to a metabolic deficiency during
fetal development. No signal from the phenyl ring protons of phenylal
anine was detected in the PKU patients (phenylalanine serum concentrat
ion less than or equal to 1.27 mM), which suggests that concentration
of phenylalanine may be lower in brain than in serum.