Work

Detection of skeletal muscle hypoperfusion during exercise using phosphorus-31 nuclear magnetic resonance spectroscopy

Year: 1986

Type: article

Abstract: Blood flow to working skeletal muscle is frequently reduced in patients with heart failure or peripheral vascular disease. To determine if phosphorus nuclear magnetic resonance (NMR) can noninvasively detect such muscle underperfusion, gated phosphorus-31 NMR spectroscopy was used to compare muscle inorganic phosphate, phosphocreatine and pH during mild wrist Rexion exercise at 0.2, 0.4 and 0.6 W in eight normal men, before and after reduction of forearm blood flow. Forearm Row was reduced by cuff inRation to a pressure determined by Doppler ultrasound to bring Dow to 40 to 60% of control. Attention was focused on the inorganic phosphate to phosphocreatine (Pi/PCr) ratio and pH, two variables potentially sensitive to muscle oxygen delivery. At rest with normal Dow, PiPCr averaged 0.12 ± 0.03 and pH averaged 7.02 ± 0.04. Exercise produced a progressive increase in Pi/PCr (0.2 W = 0.43 ± 0.12; 0.4 W = 0.75 ± 0.31; 0.6 W = 1.04 ± 0.47) and a modest decrease in pH (0.2 W = 6.94 ± 0.04; 0.4 W = 6.86 ± 0.18; 0.6 W = 6.85 ± 0.06). Flow reduction had no effect on Pi/PCr or pH at rest. In contrast, Row reduction during exercise was associated with higher P;!PCr at all three work loads (0.2 W = 0.60 ± 0.27; 0.4 W = 0.99 ± 0.50; 0.6 W = 2.00 ± 1.26 [all p < 0.05 versus normal flow]) and lower pH (0.2 W = 6.78 ± 0.12; 0.4 W = 6.69 ± 0.23; 0.6 W = 6.65 ± 0.30 [p < 0.01 versus normal Row at 0.2 and 0.4 W; P = 0.05 at 0.6 WD. Blood Row reduction also impaired the rate of recovery of the Pi/PCr ratio after exercise. These data indicate that moderllte underperfusion of working skeletal muscle increases inorganic phosphate to phosphocreatine levels and lowers intracellular pH. These metabolic changes can be continuously and non-invasively monitored by phosphorus nuclear magnetic resonance spectroscopy. This approach may prove useful in investigating skeletal muscle oxygen delivery in disease states involving reduced muscle blood flow.

Source: Journal of the American College of Cardiology

DOI: 10.1016/s0735-1097(86)80338-2

Authors: David H. Wiener, John Maris, Britton Chance, John R. Wilson

Institution: University of Pennsylvania

Language: English

Topic: Advanced MRI Techniques and Applications

Subfield: Radiology, Nuclear Medicine and Imaging

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $7,166