Magnetic resonance imaging of denervation-induced muscle atrophy: Effects of clenbuterol in the rat

We show that magnetic resonance imaging (MRI) can be used to quantify the a mount of muscle in the lower legs of adult rats and to noninvasively monito r the onset and progression of denervation-induced atrophy. Muscle cross-se ctional areas determined from 2D gradient-echo MR images allow longitudinal quantification of the protective effects of a beta (2)-adrenergic agonist clenbuterol. We also show that the estimation of clenbuterol's efficacy is improved by computation of the muscle volume. Rapid animal throughput and t he ability to accurately estimate efficacy make MRI an attractive technolog y for studying skeletal muscle atrophy and hypertrophy, allowing the evalua tion of potential therapies in longitudinal studies. (C) 2001 John Wiley & Sons, Inc.