Measurement of biceps brachii muscle cross-sectional area by extended-field-of-view ultrasound imaging technique

摘要

This study investigated the reliability of the extended-field-of-view (EFOV) ultrasonography technique and its validity against magnetic resonance imaging (MRI) for biceps brachii muscle cross-sectional area (CSA) assessment, and applied the method to examine changes in CSA following 10 sets of 3 maximal eccentric contractions of the elbow flexors. Bicep brachii CSA was assessed using both EFOV and MRI techniques at the mid-point of the upper arm. A Pearson product moment analysis showed a high correlation (r = 0.99) between the EFOV and MRI measures; however, the CSA obtained from the EFOV (12.5 ± 6.3 cm² ) was smaller (P=0.004) than that of MRI (12.9 ± 6.1 cm²). The reliability of the EFOV technique was assessed using the same scan image tracing twice (between-traces) and two images scanned from the same site (between-scans), and using the images taken from the same site one hour apart (between-measures). An Intra-class correlation (ICC) analysis showed good reliability (R=1.0) for both between-traces and between-scans, and coefficient of variation (CV) was less than 0.1 %. The reliability was also high for the measurements taken one hour apart (R=0.99, CV=0.7 %). These results show that EFOV is a valid and reliable method to assess biceps brachii CSA, but EFOV could give a smaller (~1 %) CSA than MRI. However, brachial is CSA was difficult to assess in this method, because of the limitation of the scanning technique. Biceps brachii CSA was increased (Pu3c0.05) immediately (8.7 ± 5.8 %) and 4 days (7.7 ± 6.0 %) following eccentric exercise of the elbow flexors, illustrating muscle swelling.