Imaging of Acute Appendicitis for Adult Patients

Objectives: To describe the normal and pathological radiological appearance of the appendix in the adult patient using ultrasound (US), computed tomography (CT) and magnetic resonance imaging (MRI). Furthermore, to review the utility of the aforementioned imaging modalities in different clinical contexts. Summary: The diagnosis of an inflamed appendix based on clinical evaluation, biological data and crosssectional imaging. US is the first line technique to consider and is the modality of choice for children, young and thin patients and women of childbearing age. An inconclusive ultrasound examination should lead to the realization of a CT. The appearance of the normal and pathological appendix needs to be clarified, in view of the modern technological developments of US as well as on the basis of the new CT methods (multidetector CT, with or without dual energy, low-dose acquisition). CT examinations can be performed with or without intravenous injection of contrast medium, accompanied by oral or rectal opacification, with variable diagnostic performance depending on the thickness of the sections and the possible use of reconstructions. MRI remains the second most important examination for young patients and pregnant women. In view of such technical progress, the plain films of the abdomen no longer have a role in everyday practice. Conclusion: A better knowledge of the US and cross-sectional appearance (CT-MRI) of the normal or inflamed appendix should allow the radiologist to contribute to an optimal management of this very frequent acute clinical situation. This approach reduces unnecessary radiation and negative appendectomies and optimizes the health care expenditures