MR imaging-based volumetry in patients with early-treated phenylketonuria.
OBJECTIVE
Our purpose was to specify the most severely affected brain structures in early treated phenylketonuria regarding volume loss and establish possible correlations between volume loss and plasma levels of phenylalanine (Phe).


METHODS
In 31 patients with early treated phenylketonuria and in 27 healthy volunteers, we acquired volumetric MR imaging data. Serum Phe concentrations at different times were measured as well. Semiautomatic volumetric postprocessing of the cerebellum, cerebrum (supratentorial brain tissue), hippocampus, intracranial volume, lateral ventricles, nucleus caudatus, nucleus lentiformis, pons, and thalamus, as well as the two-dimensional extension of the corpus callosum, was performed using the software BRAINS2. For each separate brain structure, the relative differences between the normal and the phenylketonuria group (delta(rel)) were calculated.


RESULTS
The cerebrum, corpus callosum, hippocampus, intracranial volume, and pons were significantly smaller in patients with phenylketonuria than in healthy patients. The volume of the lateral ventricles was significantly larger in patients with phenylketonuria than in healthy ones. The most severely affected structures were the pons (delta(rel) = 16%), hippocampus (delta(rel) = 14.5%), cerebrum (delta(rel) = 13%), and corpus callosum (delta(rel) = 10%). No significant differences were found for the basal ganglia, cerebellum, and thalamus. There were no significant correlations found between the volume of any of the different brain structures and the metabolic parameters.


CONCLUSIONS
The most severely affected brain structures in early-treated patients with phenylketonuria regarding volume loss are the cerebrum, corpus callosum, hippocampus, and pons.
Pfaendner
Nadine H
NH
Division of Neuroradiology, Department of Neurology, University of Heidelberg Medical Center, Heidelberg, Germany.
Reuner
Gitta
G
Pietz
Joachim
J
Jost
Gregor
G
Rating
Dietz
D
Magnotta
Vincent A
VA
Mohr
Alexander
A
Kress
Bodo
B
Sartor
Klaus
K
Hähnel
Stefan
S
D000328:Adult; D001921:Brain / Q000473:pathology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009929:Organ Size; D010649:Phenylalanine / Q000097:blood; D010661:Phenylketonurias / Q000097:blood / Q000175:diagnosis* / Q000178:diet therapy* / Q000503:physiopathology; D013997:Time Factors
D010649:Phenylalanine