Proton MR Spectroscopy and Imaging of a Galactosemic Patient before and after Dietary Treatment

SUMMARY: We describe how proton MR spectroscopy (1H-MR spectroscopy) was useful in elucidat-ing the diagnosis of galactosemia in an undiagnosed 6-month-old infant. In vivo 1H-MR spectroscopy of the brain showed a doublet at 3.7 parts per million, which was identified as galactitol (Gal-ol) by in vitro 1H-MR spectroscopy of the urine. Galactosemia was subsequently confirmed by laboratory tests and treatment was initiated. A follow-up brain MR imaging and 1H-MR spectroscopy study revealed resolution of white matter lesions and disappearance of Gal-ol peaks. Inborn errors of metabolism can lead to accumulation ofmetabolites in the brain and consequent abnormal peaks in the proton MR (1H-MR) spectroscopy spectrum. Patients with disorders in the carbohydrate metabolism can show ab-normal brain 1H-MR spectroscopy with unusual peaks in the region of the sugars, around 3.7 ppm. It was shown that in vitro 1H-MR spectroscopy of the urine can help in the correct assignment of these peaks.1 We report here a case where in vivo and in vitro 1H-MR spectroscopy aid in the diagnosis of galactosemia