DYNAMIC P-31 MAGNETIC-RESONANCE SPECTROSCOPY IN ARTERIAL OCCLUSIVE DISEASE - CORRELATION WITH CLINICAL AND ANGIOGRAPHIC FINDINGS AND COMPARISON WITH HEALTHY-VOLUNTEERS

RATIONALE AND OBJECTIVES. The aim of this prospective study was to exp lore muscular metabolism in arterial occlusive disease (AOD) by dynami c phosphorus-31 (P-31) magnetic resonance spectroscopy (MRS). METHODS. The authors examined 56 patients with AOD. Acquisition of up to 60 co nsecutive phosphorus spectra of the quadriceps muscle was done by ''ti me series'' in 36 seconds each. In this way, the authors achieved unin terrupted monitoring of muscle metabolism during rest, exhaustion, and recovery. During P-31 MRS, the volunteers performed an isometric and an isotonic exercise until exhaustion of the quadriceps muscle. Spectr oscopic results of 56 patients with AOD were correlated with clinical and angiographic findings and were compared with spectroscopic results of 10 age-matched healthy volunteers. RESULTS. There were no signific antly differing spectroscopic results between patients and volunteers at rest, except for an elevated ratio phosphomonoester (PME)/beta-aden osine triphosphate (ATP) in patients with AOD (0.66 +/- 0.19 versus 0. 48 +/- 0.09). Despite a sixfold duration of both of the exercises unti l exhaustion in healthy volunteers, exercise-induced changes of inorga nic phosphate (P-i)/phosphocreatine (PCr), PME/beta-ATP, and pH were s imilar in healthy volunteers and patients with AOD. Compared with maxi mal exercise-induced values of P-i/PCr, acidosis was relatively increa sed in AOD, resulting in a steeper slope of linear regression line (-0 .33 +/- 0.06 versus -0.14 +/- 0.06) between these parameters. Recovery rate of P-i/PCr was markedly prolonged in AOD (time of half recovery: 80 seconds versus 25 seconds [isometric exercise] and 70 seconds vers us 37 seconds [isotonic exercise]), whereas recovery rate of pH was no t significantly slowed down in our patients (192 seconds versus 166 se conds [isometric exercise] and 234 seconds versus 220 seconds [isotoni c exercise]). CONCLUSIONS. Dynamic P-31 MRS provides a direct judgment of muscular metabolism, which is not only influenced by macro-, but a lso by microangiopathia. Results of P-31 MRS suggest a reduced mitocho ndrial oxidative phosphorylation in AOD.