This study will explore the potential value in proper therapeutic decision and clinical outcome prediction by using integrated MR-PET system and advanced MR techniques in patients with colorectal cancer.

This research expect that the image techniques and experience in this cancer group may be valuable and helpful for others. With advantage of MR-PET in better soft tissue delineation/functional information and less radiation dose than PET-CT, the ultimate goal in both research and clinical application is to establish new diagnostic standard and management guideline by MR-PET, which can further improve clinical outcome and disease prognosis in patients colorectal cancer.

Inclusion Criteria:

1. Group 1: Patients with newly diagnosed colorectal cancers
2. Group 2: Patients with suspicious recurrent colorectal cancers

Exclusion Criteria:

1. Age <20 or >90 years old
2. Contraindication for MRI: claustrophobia or MR non-compatible devices
3. Contraindication for MR contrast medium: severe adverse reaction or impaired renal function (Cre > 2.0)
4. History of other malignancy
5. Prior arthroplasty of hip (may cause artifacts on MRI)
6. Pregnancy

This is a prospective cohort study. Patients with 50 newly diagnosed colorectal cancers and 50 patients with suspicious recurrent colorectal cancers will be enrolled.