[Imaging and PET/CT evaluation of GI tract cancers]

Imaging plays a pivotal role in the management of GI tract cancers for diagnosis, characterization, locoregional staging, metastatic work-up and follow-up during and after curative or palliative treatment. The imaging protocols should be optimized and reproducible because of their impact on therapy. Thoracic, abdominal and pelvic CT is the cornerstone of the imaging work-up, optimized and tailored to the specific GI segment involved, requiring good GI tract distension. Image interpretation of native axial and reformatted multiplanar images is routinely performed. In specific cases, additional targeted imaging with US or MRI or whole body imaging with PET/CT or MRI may be valuable. PET/CT is a complement to morphological imaging. PET allows detection of lesions otherwise undetected on morphological imaging, usually due to poor contrast with surrounding tissues, and characterization of known lesions. PET/CT is best used as an integral part of a comprehensive imaging work-up. Radiologist and nuclear medicine specialist provide complementary information. Each must be familiar with the clinical questions at hand and related stakes, and advantages and limitations of each modality to optimize treatment as part of a multidisciplinary management approach.