Maple syrup urine disease: diffusion MRI, and proton MR spectroscopy findings.

A 7-month-old boy is reported with acute metabolic crisis of maple syrup urine disease. A reversible intramyelinic type of edema was noted by diffusion MRI which completely resolved in 3 months in accordance with good clinical outcome. Proton MR spectroscopy revealed decreased NAA, and presence of methyl resonances of branched chain amino acids at 0.9 ppm, and lactic acid in the initial examination. After 3 months, NAA returned to normal, and lactic acid disappeared. The methyl resonance of branched chain amino acids, however, remained.