Multidetector CT and MRI in diseases of the GI tract

With the introduction of spiral scanning then multidetector technologies, the accuracy for diagnosing digestive tract diseases with CT has been highly improved, and CT is used more and more in the evaluation of patients with suspected gastrointestinal disorders. CT is able to demonstrate both the intramural and the extra-mural components of the disease, and has a major role in the preoperative staging and the follow-up Improvements of CT protocols, such as CT-enteroclysis, or multiplanar 2D and 3D post-processing, including now techniques for 'virtual endoscopy', lead to discuss new indications in which CT could now compete with conventional X-rays series and video-endoscopy. This precise study of the digestive wall, the peri-digestive fat, the digestive tract blood supply, may be performed by MRI, under the condition of access to high level machines and standardized protocols. MR-enteroclysis and MR-virtual colonoscopy could be performed with much lower risk for the patient, in terms of radiation dose or contrast adverse effects. Endo-luminal coils should give to MR an ultra-high resolution for analysing the different layers of the gastrointestinal wall. Learning objectives: to review how to perform CT and MRI protocols for digestive tract imaging, to recognize the CT arid MR patterns of the main digestive tract diseases, to discuss the value, limits and role of CT and MR in digestive tract diseases, to discuss the potential role of CT and MR new technological developments for digestive tract imaging in the upcoming future Conclusion: CT is nowadays a modality of choice for digestive imaging. Improvements in technologies and indications, the necessary discussion of the risks and benefits for the patient should let the radiologists consider MRI in gastrointestinal disorders as an important part of the routine activity in clinical MRI. (authors)