Effect of scanning level and XXXX on ultrasonographic cross-sectional measurements of the anterior masseter muscle.

@entity121 @entity2956 @entity2246
With the disadvantage of computed tomography showing cumulative biological effects and magnetic resonance imaging posing a problem in clinical availability and cost, several authors described the technique of ultrasonography to measure non-invasively local cross-sectional dimensions (LCSDs) of masseter muscle sites. However only few studies addressed the issue of 'technique-related factors for intra- and inter-observer reliability' to gain more consistent testing and diagnosis. The purpose of the present study was to determine (1) whether the scanning level and/or the @entity121 may affect LCSD measurements and (2) whether measurements made at identical levels may be reproducible. The study included 35 subjects with signs and symptoms of @entity2956 . Bilateral ultrasonographic investigation was performed with a linear (B-scan) 7.5 Mhz small-part transducer to register LCSDs of the anterior masseter muscle on three different levels. Scans were made on the relaxed and contracted muscle. Measurements were made in two sessions with a time interval of at least 5 min. Data were analysed for reproducibility by using the intra-class correlation coefficient (ICC) and the @entity2246 ( @entity2246 ). Scanning level and @entity121 had a significant effect on muscle measurements (P = 0.000). There was no difference in LCSD between the right and left muscle (P = 0.531). Measurements recorded at a given site were consistent across the testing sessions (P = 0.058). The scanning level with highest reproducibility was halfway between the origin and insertion (ICC = 0.92; @entity2246 = 6.2%). The data suggest that ultrasonography is a reliable method for measuring LSCDs of the anterior masseter muscle.
