On the left T1- and T2-weighted images of the thigh muscles.
Notice that there is an obvious difference between the signal intensities of the quadriceps muscle and the posterior muscles.
On the T1-weighted image only the posterior muscles contain normal fat.
On the T2-weighted image there is edema of the quadriceps, which is a sign of early muscular dystrophy.
Although the exact diagnosis cannot be made by MR, it can be helpful in suggesting a location for biopsy to determine the type of muscle degenerative disease.