[31P-mr spectroscopy of peripheral skeletal musculature under load: demonstration of normal energy metabolites compared with metabolic muscle diseases].
OBJECTIVE
31P-MR spectroscopy of skeletal muscle under exercise was used to obtain the range of normal variation and comparison was made for different neuromuscular diseases.


METHODS
41 examinations of 24 volunteers and 41 investigations in 35 patients were performed on 1.5 T MR systems (Gyroscan 515 und S15/ACSII, Philips). Localised 31P-MR spectra of the calf muscle were obtained in time series with a resolution of 12 s.


RESULTS
Two types of muscle energy metabolism were identified from the pattern of spectroscopic time course in volunteers: While the first group was characterised by a remarkable decline to lower pH values during exercise, the second group showed only small pH shifts (minimum pH: 6.48 +/- 0.13 vs 6.87 +/- 0.07, p < 10(-6)) although comparable workload conditions were maintained. The pH-values correlated well with blood lactate analysis. Patients with metabolic disorders and chronic fatigue syndrome (CFS) showed decreased resting values of PCr/(PCr + Pi) and increased pH levels during exercise. PCr recovery was significantly delayed (0.31 vs 0.65 min-1, p < 0.00005) in metabolic muscle disorders but was normal in CFS patients.


CONCLUSIONS
Findings in volunteers indicate utilisation of different metabolic pathways which seems to be related to the fibre type composition of muscle. Reduced resting levels for PCr/(PCr + Pi), altered pH time courses, and decreased PCr recovery seem to be helpful indicators for diagnosis of metabolic muscle disorders.
Block
W
W
Radiologische Klinik der Universität Bonn. block@uni-bonn.de
Träber
F
F
Kuhl
C K
CK
Keller
E
E
Lamerichs
R
R
Karitzky
J
J
Rink
H
H
Schild
H H
HH
D002239:Carbohydrate Metabolism, Inborn Errors / Q000378:metabolism*; D002334:Carnitine O-Palmitoyltransferase / Q000172:deficiency; D004734:Energy Metabolism; D006012:Glycogen Storage Disease Type V / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007625:Kearns-Sayre Syndrome / Q000378:metabolism; D017241:MELAS Syndrome / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D018482:Muscle, Skeletal / Q000378:metabolism*; D009135:Muscular Diseases / Q000378:metabolism*; D010732:Phosphofructokinase-1 / Q000172:deficiency; D010758:Phosphorus; D005082:Physical Exertion; D012016:Reference Values; D016474:Weight-Bearing / Q000502:physiology*
D010758:Phosphorus; D002334:Carnitine O-Palmitoyltransferase; D010732:Phosphofructokinase-1