Imaging Advances on CT and MRI in Colorectal Cancer

Colorectal cancer (CRC) is the most common gastrointestinal neoplasm. Imaging plays a key role in the primary diagnosis, risk stratification and prognosis, therapy planning, treatment response assessment, follow-up, and, to some extent, also in prevention of CRC. The most used imaging modalities for the evaluation of these tumours are computed tomography (CT) and magnetic resonance imaging (MRI). We review the literature and, drawed on our own experience, evaluate recent innovations in hardware, software (including artificial intelligence), and analytic tools that are opening new possibilities to CT and MRI imaging in CRC. Finally, we examine the advantages and disadvantages of these techniques. Advances in CT technology have improved image quality and reduced radiation exposure to patients and have allowed a paradigm shift from an imaging modality that provided solely anatomical data to one that can also provide functional information. In addition, technological improvements in MRI have made possible a faster and more robust imaging technique and the generation of new data of tumour phenotype. All these advances have expanded the clinical capabilities of these techniques in colorectal tumours. Recent developments and emerging technologies in CT and MRI are changing the management of CRC patients in many clinical scenarios. Current evidence supports the clinical application of many of them. In other cases, such as quantitative imaging, multiparametric assessment, and radiomics/radiogenomics, important problems of standardization and reproducibility of these techniques persist that limit their introduction in daily clinical practice.