One typical obstacle in quantitative MRI lies in the delineation of the regions of interest. When not absolutely necessary, per-muscle analyses are often abandoned, resulting in the loss of a wealth information. A software dedicated to accelerated segmentation of muscle images was recently introduced. It was tested here on the calf muscles of healthy volunteers and Duchenne patients. Results showed an important gain in average speed and were close to the manual segmentation used as reference. Thus, the tested software proved to be a valuable tool for quantitative analysis of skeletal muscle NMR images.