Phenylketonuria: findings at MR imaging and localized in vivo H-1 MR spectroscopy of the brain in patients with early treatment

Radiology. 1996 Nov;201(2):413-20. doi: 10.1148/radiology.201.2.8888233.


Purpose: 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.

Materials and 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.

Conclusion: A synergistic use of MR imaging and MR spectroscopy may help elucidate both the pathogenesis of brain dysfunction and clinical treatment policies in PKU.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Brain / pathology*
  • Brain Chemistry*
  • Child
  • Evoked Potentials, Visual
  • Female
  • Humans
  • Magnetic Resonance Imaging*
  • Magnetic Resonance Spectroscopy*
  • Male
  • Neuropsychological Tests
  • Phenylketonurias / metabolism
  • Phenylketonurias / pathology*
  • Phenylketonurias / physiopathology
  • Phenylketonurias / therapy