Phenylketonuria: findings at MR imaging and localized in vivo H-1 MR spectroscopy of the brain in patients with early treatment.
OBJECTIVE
To characterize white matter changes in early-treated phenylketonuria (PKU) with magnetic resonance (MR) imaging and hydrogen-1 MR spectroscopy and to correlate these findings to biochemical control and brain function.


METHODS
Fifty-one patients aged 12-33 years underwent T1-, T2-, and proton-density-weighted MR imaging and testing of intelligence, visual evoked potentials (VEPs), and neuropsychologic status (29 adult patients only). H-1 MR spectroscopy was performed in eight patients to determine brain metabolite concentrations, including phenylalanine (PHE) concentration, and brain compartmentation.


RESULTS
MR imaging revealed a high frequency of supra- and infratentorial abnormalities. MR imaging grade, which was based on areas of high signal intensity on T2-weighted images, showed statistically significant correlation with long-term biochemical control and neuropsychologic test results but not with intelligence quotient or VEPs. H-1 MR spectroscopy revealed normal metabolite levels, except for increased PHE levels. It also showed enlarged cerebrospinal fluid-like compartments in affected white matter, related to plasma and brain concentrations of PHE and MR imaging grades.


CONCLUSIONS
A synergistic use of MR imaging and MR spectroscopy may help elucidate both the pathogenesis of brain dysfunction and clinical treatment policies in PKU.
Department of Pediatric Neurology, University of Heidelberg, Germany.
J
J
Pietz
R
R
Kreis
H
H
Schmidt
U K
UK
Meyding-Lamadé
A
A
Rupp
C
C
Boesch
D000293:Adolescent; D000328:Adult; D001921:Brain / Q000473:pathology*; D001923:Brain Chemistry; D002648:Child; D005074:Evoked Potentials, Visual; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009483:Neuropsychological Tests; D010661:Phenylketonurias / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology / Q000628:therapy