Quantitative proton-decoupled 31P MRS and 1H MRS in the evaluation of Huntington's and Parkinson's diseases.
OBJECTIVE
To determine cerebral energy status in patients with Huntington's disease (HD) and Parkinson's disease (PD).


METHODS
The study included 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 single volumes in putamen of basal ganglia (BG), occipital gray matter, and posterior parietal white matter; in addition, quantitative phosphorus and proton-decoupled phosphorus MRS of superior biparietal white and gray matter was done. Outcome measures were quantitative metabolite ratios and millimolar concentrations of neuronal and glial markers, creatine (Cr) and adenosine triphosphate (ATP), and intracellular pH.


RESULTS
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 locations 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-containing compounds (Cho, increased), and myoinositol (mI, increased) were demonstrable in all patient's individually and in summed spectra but were insufficient to make diagnosis possible in the individual patient.


CONCLUSIONS
Previously described failure of global energy metabolism in HD was not confirmed. However, quantitative 1-hydrogen MRS and decoupled 31-phosphorus MRS are sensitive to +/-10% alterations in key cerebral metabolites, and may be of value in noninvasive monitoring of appropriate therapies.
Hoang
T Q
TQ
Huntington Medical Research Institute, Pasadena, CA 91105, USA.
Bluml
S
S
Dubowitz
D J
DJ
Moats
R
R
Kopyov
O
O
Jacques
D
D
Ross
B D
BD
D000255:Adenosine Triphosphate / Q000032:analysis; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001479:Basal Ganglia / Q000166:cytology / Q000378:metabolism; D003404:Creatinine / Q000032:analysis; D004734:Energy Metabolism / Q000502:physiology; D006801:Humans; D006816:Huntington Disease / Q000175:diagnosis*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008875:Middle Aged; D009412:Nerve Fibers / Q000737:chemistry / Q000378:metabolism; D009474:Neurons / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D010300:Parkinson Disease / Q000175:diagnosis*; D010759:Phosphorus Isotopes; D011522:Protons
D010759:Phosphorus Isotopes; D011522:Protons; D000255:Adenosine Triphosphate; D003404:Creatinine