Pilot Study: Dynamic Contrast-enhanced Magnetic Resonance Imaging(DCE-MRI)for Assessing Tumor Vascularity and Permeability in Soft Tissue Sarcoma Treated With Preoperative Radiotherapy Followed by Surgical Resection

Inclusion Criteria: 1. Pathologically confirmed soft tissue sarcoma. 2. Age ≥ 18. 3. ECOG 0-1. 4. Able to receive preoperative radiotherapy followed by surgical resection. 5. Able to provide treatment consent forms that conforms to federal and institutional guidelines. 6. Have adequate kidney function for safe administration of gadolinium contrast, as determined by current Department of Radiology MRI guidelines. 7. Creatinine clearance either by 24 hour collection or nomogram: Creatinine clearance (CC) \> 50 ml/min is determined by 24 hour collection or nomogram: CC male = (140 - age) x (wt. in kg)/(Serum Cr mg/dl) x 72 CC female = 0.85 x (CC male) Exclusion Criteria: 1. Patients have claustrophobia, iron or metal in the MRI scan site or pacemaker which are contraindicated for MRI scan. 2. patients have pacemaker or defibrillator and contraindicated to MRI images 3. Patients are allergic to gadolinium IV contrast. 4. Patients have acute or chronic renal insufficiency and contraindicated to gadolinium contrast enhancing MRI. 5. Patient had previous radiation to the same disease site. 6. Patient had chemotherapy prior to preoperative radiotherapy. 7. Patients that are pregnant. Patients that may become pregnant must have a negative pregnancy test prior to enrolling.