Validation of an MRI analysis for thigh muscle and fat composition changes in strength training
Bezerra, P, Zhou, S, Davie, AJ, Fuller, H & Hooper, A 2006, 'Validation of an MRI analysis for thigh muscle and fat composition changes in strength training', Journal of Science and Medicine in Sport, vol. 9, suppl. 1, p. 42.
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Publisher's version of article available at http://dx.doi.org/10.1016/j.jsams.2006.12.099
This pilot study aimed to validate an MRI analysis for thigh muscle and fat composition changes following strength training. Fifteen healthy men were randomly assigned into a control (CG), voluntary isometric knee extension (VG) or electromyostimualtion superimposed voluntary training (EG) group. Subjects trained the right leg three sessions per week for 6 weeks. MRI images of both thighs were obtained using a 1.5-T system, and analysed using ImageJ software. The cross-sectional areas of the thigh (CSA-T), fat (CSA-F) and muscle (CSA-M) tissues in MRI images, and circumferences and skinfolds, were measured at middle-point of the thigh, and at 5 cm above and 5 cm below this point. Analyses of 30 images in different formats (8- and 16-bit) were replicated to examine the reproducibility. Results showed high levels of reproducibility within either the 8- or 16-bit images (ICC 0.96–0.99). However, significant differences existed between the measurements of the two formats of images. From the results of all subjects, both CSA-T and CSA-M (in 8-bit images) showed a high correlation with the circumference (Pearson correlation r = 0.99 and r = 0.82, p < 0.01), while CSA-F was well correlated with the skinfold (r = 0.90, p < 0.01). Comparing the pre and post training measurements, variations in CSA-M of the trained limb of VG, EG and CG were +5%, +6% and +0.4%, and that of the untrained limb were +3%, +4% and +0.3%; and that in CSA-F of the trained limb were −1%, −19% and −10%, and that of the untrained limb were +0.6%, −14% and −7%, respectively, although these variations were not statistically significant.