This study will use diffusion weighted MRI (DWI MRI) and dynamic-contrast enhanced MRI (DCE MRI) techniques to detect changes in sarcoma tumour vasculature. The main aims of this study are to correlate histological response of soft tissue sarcoma after pre-operative radiotherapy with several pre-treatment DCE and DWI MRI parameters and to assess the impact of these on early response prediction. Detected changes may reflect the sensitivity of the tumour to radiotherapy and may be associated with long term outcomes after treatment.

15 patients normally having pre-operative radiotherapy as part of their sarcoma treatment will be recruited to this study.

Patients will have an additional three specialised MRI scans: one prior to the start of radiotherapy, one during the second week of radiotherapy while on treatment and one scan a week before surgery but after the completion of radiotherapy.

Post-operatively, results of the histological examination of the sarcoma will be correlated to both the MRI scan data and outcomes after treatment

Inclusion Criteria:

• Patients must have histologically confirmed diagnosis of intermediate/high grade soft tissue sarcoma (STS)
• Patients must be suitable for treatment with preoperative radiotherapy and radical surgery
• Standard radiological assessments (CT or MRI) may have already been performed but must be done within 4 weeks of starting radiotherapy
• Patient must have measurable disease on CT/MRI imaging
• ECOG performance status 0-2
• Adequate pre-treatment haematological and biochemical parameters
• Age greater than or equal to 18 years
• No significant co-morbidity thereby excluding patient from having radical treatment.
• No previous treatment for diagnosis of STS including neo-adjuvant chemotherapy
• Women of child bearing age MUST have a negative pregnancy test prior to study entry and be using an adequate contraception method unless child bearing potential has been terminated by surgery/radical radiotherapy
• Patients must have given written informed consent

Exclusion Criteria:

• Patients with cardiac pacemakers, cochlear implants, intraocular foreign bodies or any other MRI incompatibility factors (e.g. recent surgery).
• Patients with a known history of anaphylactic reaction to contrast material for MRI
• Previous administration of gadoxetic acid or other contrast material 24hr prior to or after the MRI
• Any evidence of severe or uncontrolled systemic diseases which, in the view of the investigator, makes it undesirable for the patient to participate in the trial
• Evidence of significant clinical disorder or laboratory finding which, in the opinion of the investigator makes it undesirable for the patient to participate in the trial
• Any other serious uncontrolled medical conditions
• Clinical evidence of metastatic disease
• Any pregnant or lactating woman
• Any patient with a medical or psychiatric condition that impairs their ability to give informed consent
• Evidence of impaired renal function, serum creatinine >1.5x upper limit of normal