QUANTITATIVE PROTON-DECOUPLED P-31 MRS AND H-1 MRS IN THE EVALUATION OF HUNTINGTONS AND PARKINSONS DISEASES

Objective: To determine cerebral energy status in patients with Huntin gton's disease (HD) and Parkinson's disease (PD). Methods: The study i ncluded 15 patients with DNA-proven, symptomatic HD and five patients with medically treated, idiopathic PD, all of whom were candidates for neurotransplant treatment, as well as 20 age-related normal subjects. Quantitative noninvasive, MRI-guided proton MRS was performed of sing le volumes in putamen of basal ganglia (BG), occipital gray matter, an d posterior parietal white matter; in addition, quantitative phosphoru s and proton-decoupled phosphorus MRS of superior biparietal white and gray matter was done. Outcome measures were quantitative metabolite r atios and millimolar concentrations of neuronal and glial markers, cre atine (Cr) and adenosine triphosphate (ATP), and intracellular pH. Res ults: In volume-corrected control BG (10.46 +/- 0.37 mM), [Cr] was 29% (p < 0.05) higher than in control gray matter (8.10 +/- 1.04 mM). In HD and PD, energy metabolism was not abnormal in the four cerebral loc ations measured by MRS. No increase in cerebral lactate or decrease in phosphocreatine and ATP was detected. Small, systematic abnormalities in N-acetylaspartate (NAA, decreased), Cr (decreased), choline-contai ning compounds (Cho, increased), and myoinositol (mI, increased) were demonstrable in all patient's individually and in summed spectra but w ere insufficient to make diagnosis possible in the individual patient. Conclusion: Previously described failure of global energy metabolism in HD was not confirmed. However, quantitative 1-hydrogen MRS and deco upled 31-phosphorus MRS are sensitive to +/-10% alterations in key cer ebral metabolites, and may be of value in noninvasive monitoring of ap propriate therapies.