Magnetic resonance imaging (MRI) is presently the best study for assessing the size and extent of the patient's sarcoma. Many sarcomas contain fat that can interfere with the accuracy of sarcoma detection. The investigators have developed a new MRI method that can suppress all the fat signals in the patient's tumor and this may improve the investigators' ability to see the patient's sarcoma. The purpose of this study is to determine if the investigators' new fat-free imaging methods provides them with images that are better than, equal to, or worse than those images obtained by standard MRI methods. This study may help the investigators develop a more accurate MRI examination.