Diffusion magnetic resonance imaging in intermediate form of maple syrup urine disease.

An 8-year-old boy with the intermediate variant of maple syrup urine disease is reported. On b = 1000 s/mm2 (heavily diffusion weighted) images of diffusion magnetic resonance imaging, there was symmetric high signal in the globus pallidus, mesencephalon, dorsal pons, and nucleus dentatus, consistent with restriction of the mobility of water molecules. Apparent diffusion coefficient (ADC) maps revealed low ADC values ranging from 0.42 to 0.56 x 10(-3) mm2/s in these regions, compared to those of apparently unaffected regions in the brain parenchyma ranging from 0.63 to 0.97 x 10(-3) mm2/s. It is suggested that the areas of increased signal (and low ADC values) are the result of dysmyelination as a reflection of disorganized tissue integrity.