Diffusion MRI findings in phenylketonuria

Area of Science:

• Neuroimaging
• Metabolic Disorders
• Radiology

Background:

• Phenylketonuria (PKU) is an inherited metabolic disorder requiring early dietary intervention.
• Mentally normal PKU patients under long-term dietary control were assessed using diffusion MRI.
• Understanding brain changes in treated PKU is crucial for long-term management.

Observation:

• Diffusion MRI was performed using spin-echo, echo-planar imaging at 1.5 T.
• Heavily diffusion-weighted (b=1000 mm²/s) images and apparent diffusion coefficient (ADC) values were analyzed.
• Two distinct diffusion patterns were observed in the two patients studied.

Findings:

• Restricted diffusion pattern: high signal on b=1000 images with low ADC values (0.46–0.57 x 10⁻³ mm²/s).
• Increased diffusion pattern: normal signal on b=1000 images with high ADC values (1.37–1.63 x 10⁻³ mm²/s).
• These findings suggest potential differences in brain histopathology or disease progression.

Implications:

• Diffusion MRI may reveal distinct neuropathological states in treated PKU.
• Further research is needed to correlate these patterns with specific histopathological findings.
• This could lead to more refined diagnostic or prognostic tools for PKU patients.