Reproducibility of estimation of blood flow in the human masseter muscle from measurements of 133Xe clearance.
The reproducibility of estimations of the masseter intramuscular blood flow (IMBF) was assessed bilaterally within and between clinical sessions. The 133Xe clearance in nine normal individuals was measured before, during, immediately after, and after endurance of isometric contraction at an attempted level of 50% of maximum voluntary clenching contraction. An overall low reproducibility of the estimations was found. This result was probably caused by uncertainties about the exact site of intramuscular 133Xe deposition, errors in assessment of the plots of clearance, and variabilities in the relative contraction levels sustained and, especially, in the overall muscle effort. In agreement with previous reports concerning other skeletal muscles, the 133Xe clearance method provided inconsistent estimates of absolute values of IMBF also in this clinical setting. Although there was a high intra-individual variation in the relative level of isometric contraction sustained, the endurance test induced distinct changes in IMBF, among which the estimate of post-endurance hyperemia was the most consistent for each individual. Therefore, measurements of 133Xe clearance seem to be useful to detect intra-individual changes in masseter IMBF resulting from isometric work.
Monteiro
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Department of Clinical Oral Physiology, School of Dentistry, Karolinska Institutet, Huddinge, Sweden.
Kopp
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D004576:Electromyography; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D008406:Masseter Muscle / Q000098:blood supply*; D008410:Masticatory Muscles / Q000098:blood supply*; D012039:Regional Blood Flow; D015203:Reproducibility of Results; D014980:Xenon Radioisotopes / Q000493:pharmacokinetics
D014980:Xenon Radioisotopes