**1. Introduction**

The preoperative imaging diagnosis of rectal cancer lies at the heart of oncological staging and has a crucial influence on patient management and therapy planning. Computer tomography (CT) with intravenous contrast medium is the standard method to exclude metastases in the liver and lungs. However, the current state-of-the-art modality for local staging of the tumor is magnetic resonance imaging (MRI). Its new development, 3D MRI, seems to bring additional valuable possibilities for the surgery planning of rectal cancer.

### **1.1 Multidisciplinary management team (MDT) in rectal MRI**

Due to the multitude of treatment options available today for the treatment of rectal cancer, it became an international standard (e.g. in [1]) that a multidisciplinary team (MDT) discusses each patient situation pre-therapeutically in a tumor conference. This procedure ensures that all therapeutic options are considered as necessary for the patient's benefit. The basis for these discussions and decisions of the MDT is in most cases the imaging findings. Magnetic resonance imaging (MRI) of the pelvis has become of central importance in recent years, as it can best depict the relationship of the tumor to the mesorectal fascia and the other structures of the pelvis.

In order to make good therapeutic decisions, an MRI must not only be carried out in a technically adequate manner, but must also be interpreted and presented accordingly. Moreover, the radiologist should also have a basic understanding of the various available therapy options. In particular, it is important to understand the surgery relevant aspects in order to have a target-oriented interdisciplinary discussion. Similarly, the treatment partners should also have basic knowledge of the findings and interpretation of MRI in order to be able to understand the findings of the radiologist.
