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.
Pietz
J
J
Department of Pediatric Neurology, University of Heidelberg, Germany.
Kreis
R
R
Schmidt
H
H
Meyding-Lamadé
U K
UK
Rupp
A
A
Boesch
C
C
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