Muscle Health Measurements Using Electrical Impedance Myography

This study is being done to further develop a device, the mScan, to measure muscle health as compared to measurements of muscle health using MRI (magnetic resonance imaging). This device is held against the skin and uses Electrical Impedance Myography (EIM). EIM uses a very small, noninvasive (e.g. no needles), brief (about 6 seconds), and painless electrical current to measure the muscle. The investigators will look at how the mScan predicts the muscle measurements seen on MRI in people with and without muscle disease. The investigators hope that this can be used in the future as a quick, convenient and less time-consuming way than MRI to assess muscle health. This could be used to measure how well treatments for different muscle disorders are working over a period of time.