Abstract
BACKGROUND: P-31-MR spectroscopy is a technique for undertaking a comprehensive evaluation of muscle metabolism. The goal of this study was to compare patients with mild and severe lower limb ischemia measured by P-31-MR spectroscopy at rest and during exercise.
METHODS: Sixteen non-diabetic mild peripheral arterial occlusive disease (PAOD) patients, 23 diabetic PAOD patients with severe ischemia and 19 healthy controls were examined by rest and dynamic P-31-MR spectroscopy with a P-31-MR system equipped with an 3T MR-compatible home-made pedal ergometer. Signal intensity ratios of phosphorous metabolites to the sum of all P-31 intensities (P-tot) and pH were obtained at rest.
The PCr drop (Delta PCr), time recovery constant of PCr (tau PCr), pH at the end of the exercise (PHend), and mitochondrial capacity (Q(max)) were calculated from dynamic MR spectra. RESULTS: Diabetic PAOD patients with severe ischemia differed from controls in both rest (PCr/Pi, beta ATP/P-tot pH) and dynamic (Q(max), pH(end), tau PCr) parameters.
PAOD patients with mild ischemia differed from controls only in Q(max) and PHend. Rest parameters of the non-diabefic PAOD patients did not differ from control values excluding rest pH which was higher in both patient groups.
CONCLUSIONS: A combination of rest and dynamic P-31-MR spectroscopy can distinguish among all three groups of subjects. On the other hand, examination at rest is sufficient for differentiation between patient groups and verification of severe ischemia.