Quantitative analysis of energy metabolism in human muscle using SLOOP 31P-MR-spectroscopy.
OBJECTIVE
Energy metabolism is vital for regular muscle function. In humans, in-vivo analysis using (31)P-MR-spectroscopy (MRS) is mostly restricted to semiquantitative parameters due to technical demands. We applied Spatial Localization with Optimal Pointspread Function (SLOOP) for quantification in human skeletal and cardiac muscle.


METHODS
10 healthy volunteers and 4 patients with myotonic dystrophy type 1 were examined using a 1.5 T system (Magnetom VISION) and chemical shift imaging (CSI) for data collection. Concentrations of PCr, ATP and Pi as well as PCr/ATP ratios were calculated by SLOOP.


RESULTS
Concentrations of PCr, ATP and Pi were 29.9 +/- 3.4, 7.1 +/- 0.9 and 5.7 +/- 1.2 [mmol/kg] in normal skeletal muscle, corresponding to previously published studies. Two of the patients with a duration of disease longer than 10 years and a pronounced muscle weakness showed a significant decrease of PCr and ATP in skeletal muscle below 10 and 5 mmol/kg. One of these patients had an additional reduction of PCr in cardiac muscle.


CONCLUSIONS
With MRS and SLOOP, a more accurate quantitative assessment of metabolism is now available in skeletal and cardiac muscle. Longitudinal studies of larger patient groups will allow to better describe the metabolic disorder in muscle disease over time. Moreover, these techniques offer a new way to quantify treatment effects in future trials.
Beer
M
M
Institut für Röntgendiagnostik der Universität Würzburg, Germany. meinrad.beer@mail.uni-wuerzburg.de
Schneider
C
C
Köstler
H
H
Buchner
S
S
Sandstede
J
J
Toyka
K V
KV
Hahn
D
D
D000328:Adult; D001706:Biopsy; D018450:Disease Progression; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation / Q000379:methods*; D008297:Male; D018908:Muscle Weakness / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D009223:Myotonic Dystrophy / Q000378:metabolism*; D012016:Reference Values