[Techniques for ultrasound imaging of meniscus lesions. Experimental principles].

The fact that a lesion of the knee meniscus presents in ultrasound as a hard, glaring reflection of sound waves is considered to be well established today. Nevertheless, different examiners report variable results. When looking for the reasons for these variations, we tried to determine whether different examination techniques are the cause or the technical equipment used. Thus we ran tests with isolated menisci containing artificial lesions in a waterbath. We found that sound waves falling on the object at an angle of 45 degrees in reference to the meniscal axis provide optimal imaging of the lesion. In contrast, the reflection of sound waves is very weak when the angle of incidence is about 10 degrees. As a result of these tests, a dynamic examination with tilting movements of the scanner in the vertical axis is recommended. The method of visualizing the menisci perpendicular to the axis of the leg was found to be much more difficult without yielding additional information. We thus suggest that this method of examination should not be used.