Dynamic phosphorus-31 magnetic resonance spectroscopy in arterial occlusive disease: effects of vascular therapy on spectroscopic results.
OBJECTIVE
The aim of the authors' prospective study was to explore therapy-induced changes of muscular metabolism in arterial occlusive disease (AOD).


METHODS
Before and after vascular therapy, respectively, 31 patients with AOD were examined by dynamic phosphorus-31 (31P) magnetic resonance spectroscopy (MRS) at 1.5 T; in the magnet, the quadriceps muscle was stressed by an isometric and an isotonic form of exercise until exhaustion, respectively. Twenty-three patients were treated by standardized percutaneous transluminal angioplasty; eight patients underwent a vascular operation.


RESULTS
Vascular therapy induced a marked improvement of clinical and angiographic results. At the same work load, exercise-induced metabolic changes of the quadriceps muscle were significantly less pronounced after the vascular therapy: maxima of the ratio inorganic phosphate (Pi)/phosphocreatine (PCr) (isometric exercise: 0.34 [after therapy] versus 0.44 [before therapy]; isotonic exercise: 0.36 [after therapy] versus 0.51 [before therapy]) as well as minima of pH (isometric exercise: 7.00 [after therapy] versus 6.93 [before therapy]; isotonic exercise: 7.00 [after therapy] versus 6.93 [before therapy]). In relation to maximal values of Pi/PCr, the extent of acidosis was smaller after vascular therapy, resulting in a flatter slope of the regression line between these parameters (b = -0.24 +/- 0.10 versus b = -0.31 +/- 0.09). After both of the exercises, time of half recovery of Pi/PCr was significantly shorter after vascular therapy (isometric exercise: 43 seconds [after therapy] versus 83 seconds [before therapy]; isotonic exercise: 42 seconds [after therapy] versus 57 seconds [before therapy]).


CONCLUSIONS
After effective vascular therapy, minor exercise-induced metabolic changes (increased "work/energy cost-index"), a decreased contribution of anaerobic glycolysis to total adenosine triphosphate production as well as a markedly increased recovery rate of Pi/PCr are unequivocal spectroscopic proofs of an improved oxidative metabolism of muscle cells because of increased tissue perfusion.
Schunk
K
K
Department of Radiology, University Hospital Mainz, Germany.
Romaneehsen
B
B
Rieker
O
O
Düber
C
C
Kersjes
W
W
Schadmand-Fischer
S
S
Schmiedt
W
W
Thelen
M
M
D000255:Adenosine Triphosphate / Q000378:metabolism; D000328:Adult; D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D001157:Arterial Occlusive Diseases / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000628:therapy*; D004734:Energy Metabolism; D015444:Exercise / Q000502:physiology; D005260:Female; D005263:Femoral Artery / Q000378:metabolism / Q000473:pathology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007083:Iliac Artery / Q000378:metabolism / Q000473:pathology; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D010725:Phosphocreatine / Q000378:metabolism; D010759:Phosphorus Isotopes; D011446:Prospective Studies; D011859:Radiography; D018709:Statistics, Nonparametric
D010759:Phosphorus Isotopes; D010725:Phosphocreatine; D000255:Adenosine Triphosphate