[Knee imaging: what is the best modality].

A wide range of exams are available for imaging the knee: standard radiography, ultrasound, bone scintigraphy, CT scan, arthroscan, MRI, arthro-MRI. The radiologist must be aware of the performance capacities of each technique in order to orient the clinician's choice towards the most appropriate exam in a given clinical situation. In the first part of this paper, we examine the performances, advantages and disadvantages of each technique: exam conditions (patient position, incidence, slice thickness, sequence.) are detailed as required. The second part is a practical guide for some typical clinical situations with decision trees for ordering necessary and sufficient explorations.