The dynamic investigation arises as very useful during ongoing muscle injuries with large hematomas, which at times are not well definable in their extension and therefore can be placed in the differential diagnosis together with any growths of benign or malignant nature.

That is the case of Fig. 8.2, in which various sequences performed by dynamic ultrasound, elastosonography, and MRI are featured, demonstrating a large lesion partly colliquated and partly structured, referring to a possible space-occupying lesion.

In Fig. 8.3, it becomes fully highlighted, during the dynamic phases of contraction and flexed extension of the lower limb that the mentioned lesion is constituted by a large hematoma involving the medial twin head muscle, surely more perceivable during the dynamic phases.

Another extremely useful application of the mentioned method is provided through the fusion method (Fig. 8.4), which allows the overlap even in dynamic with the ultrasound investigation performed in real time.

Thus it is possible to check in a more accurate manner the possible alterations not underlined by either method and, above all, to use this method during the follow-up, in order to examine and better assess the evolution of the clinical picture.

Certainly a suitable utilization is carried out at the level of the extensive muscle lesions, during which at times the ultrasound examination does not allow a panoramic picture, so to provide certain and well-defined details of the extension of the mentioned lesion.

During the active and passive contraction phases, the presence of a partial lesion of the quadriceps muscle of the femur at the distal insertion is featured in Fig. 8.5, with evident greater retraction during the active contraction phase.

The employment of the dynamic method proves to be equally useful in ongoing plotted detachments of the osteotendon junction, such as the case of the anterior inferior iliac spine investigated through computed tomography plus 3D reconstruction (Fig. 8.6a) and better defined by the means of the dynamic MRI method, which during the phase of contraction shows in a more accurate manner the diastasis of the bone fragment retracted through the contraction of the adjacent muscle components (Fig. 8.6b).

The employment of the dynamic method in ongoing lesions caused by compression proves to be of fundamental importance, which can be difficult to approach by the means of the ultrasound investigation, especially in relation to the formation of a wide groove which does not allow a suitable probe support.