Diffusion tensor images in children with early-treated, chronic, malignant phenylketonuric: correlation with intelligence assessment.
OBJECTIVE
Diffusion tensor (DT) images can provide information about the nature of white matter changes, including axonal loss and demyelination. We applied DT imaging to verify white matter changes in patients with malignant phenylketonuria (PKU) and to correlate the findings with clinical intelligence quotients (IQs).


METHODS
We compared DT images with T2-weighted images in 12 patients with early-treated, chronic, stable malignant PKU and 12 age-matched control subjects. DT parameters included first, second, and third eigenvalues (EV1-3), apparent diffusion coefficients (ADCs), and fractional anisotropy (FA). Regions of interest were placed the frontoparietal, parieto-occipital, frontal and central white matter and in the anterior and posterior corpus callosum. Eight patients older than 3 years underwent IQ assessment including verbal, performance, and full-scale IQ tests.


RESULTS
In the eight patients older than 3 years, no definite abnormal signal intensity changes were found on T2-weighted images. EV2, EV3, and FA of the parieto-occipital white matter were significantly different in patients and control subjects older than 3 years. EV3 and ADC of the parieto-occipital white matter were significantly and negatively correlated with verbal IQ (r = -0.79, P = .04) and performance IQ (r = -0.93, P = .03). FA of the parieto-occipital central white matter was positively correlated with verbal IQ (r = 0.75, P = .05).


CONCLUSIONS
Though treated early, patients with chronic, stable malignant PKU had abnormal DT findings in the parieto-occipital central white matter. EV2, EV3, and FA maps are potential tools for demonstrating brain changes due to malignant PKU.
Peng
Steven Shinn-Forng
SS
Department of Medical Imaging, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
Tseng
Wen-Yih Isaac
WY
Chien
Yin-Hsiu
YH
Hwu
Wuh-Liang
WL
Liu
Hon-Man
HM
D006916:5-Hydroxytryptophan / Q000008:administration & dosage; D001369:Axons / Q000473:pathology; D001708:Biopterins / Q000008:administration & dosage / Q000031:analogs & derivatives*; D001925:Brain Damage, Chronic / Q000151:congenital* / Q000175:diagnosis / Q000628:therapy; D002540:Cerebral Cortex / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D003131:Combined Modality Therapy; D003337:Corpus Callosum / Q000473:pathology*; D038524:Diffusion Magnetic Resonance Imaging; D004292:Dominance, Cerebral / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007360:Intelligence / Q000502:physiology*; D007980:Levodopa / Q000008:administration & dosage; D008297:Male; D015997:Neonatal Screening; D009413:Nerve Fibers, Myelinated / Q000473:pathology; D010649:Phenylalanine / Q000008:administration & dosage; D010661:Phenylketonurias / Q000175:diagnosis / Q000628:therapy*; D011247:Pregnancy
D001708:Biopterins; D007980:Levodopa; D010649:Phenylalanine; D006916:5-Hydroxytryptophan; C003402:sapropterin