Affiliations: Department of Physiology II, School of Medicine, Iwate Medical University, Morioka, 020‐8505, Japan | Department of Radiology, School of Medicine, Iwate Medical University, Morioka, 020‐8505, Japan | Department of Neurosurgery, School of Medicine, Iwate Medical University, Morioka, 020‐8505, Japan | High Field Magnetic Resonance Imaging Research Institute, Iwate Medical University, Takizawa, 020‐0173, Japan
Abstract: The temperature and pH of human lower leg muscles were estimated noninvasively using 1H‐NMR spectroscopy at 3.0 and 1.5 T on five normal volunteers (21M, 24M, 27M, 34M, 47M). The chemical shifts of water and imidazole protons relative to cholines (–N+CH3) or creatines (–CH3) could be used as the temperature and pH probes, respectively [1–4]. Using the chemical shift, estimated values of the temperature in gastrocnemius (GAS; shell region) and soleus muscles (SOL; core region) under ambient temperature (21–25°C) were 33.6±0.4 and 35.3±0.4°C (mean±SE), respectively (significantly different; P<0.01). The values of pH in these muscles were estimated to be 6.97±0.01 and 6.96±0.02, respectively. Alternation of the surface temperature of the lower leg from 40 to 10°C significantly changed the temperature in GAS (P<0.0001) from 35.8±0.4 to 26.2±1.2°C and the pH in GAS rose from 6.95±0.01 to 7.01±0.01 (P<0.01). However, the values of pH and temperature in SOL were not significantly affected by this maneuver. These results indicate that the pH in GAS was moderately changed by muscle temperature (r=−0.59, P<0.01), and its change was estimated to be −0.005 pH units/°C.
Keywords: Magnetic resonance spectroscopy, temperature, pH, human lower leg muscles
Journal: Spectroscopy, vol. 16, no. 3-4, pp. 183-190, 2002
