**5. Conclusions**

Ultrasound is the first-line technique in the study of muscle traumas, as it is readily available, has a good cost-benefit profile, enables assessment of muscle dynamics and provides reliable assessment of the extent of damage. Musculoskeletal Ultrasound has been shown to be effective for many applications related to sports medicine and has proved itself as one of several imaging methods invaluable to the diagnosis of sport medicine–related abnormalities. Some advantages of Ultrasound over MR imaging include portability, accessibility, high resolution, and relative lower cost. More importantly, dynamic imaging under Ultrasound visualization allows diagnoses that cannot be made with routine MR imaging. Additionally, direct imaging correlation with patient symptoms provides important information to the referring clinicians.

There however some disadvantages.

Among these is the fact that its resolution is limited to the tertiary bundle, it is unable to identify alterations to secondary and primary bundles and myofibrils, and cannot visualise deep muscle planes. For these reasons, Ultrasound may yield negative results in lesions with only slight muscle alterations, such as contracture, lengthening and DOMS. [4]

Other disadvantages of Ultrasound include operator dependence and long learning curve. This can be minimized, however, with proper training and standardized technique.

Musculoskeletal Ultrasound has recently experienced an increase in popularity for several reasons. Advances in technology including the advent of high-frequency transducers have markedly improved image resolution. [2]

Additionally, the relative low expense of Ultrasound compared with MR imaging has made this an attractive alternative imaging method for many indications. Ultrasound does have several potential advantages over MR imaging. Evaluation of a soft tissue process near metal orthopaedic hardware is possible with Ultrasound without the artefact that limits MR imaging. Additionally, Ultrasound can immediately guide percutaneous procedures when an abnor‐ mality, such as a joint effusion, is identified. Ultrasound also allows a dynamic evaluation of joints detecting abnormalities that may not be present during MR imaging positioning. Lastly, the improved resolution of superficial structures demonstrates subtle abnormalities that may be difficult to visualize with MR imaging. Current ultrasound technology produces in-plane resolutions of 200 to 450 bm and section thicknesses of 0.5 to 1 mm. For these reasons muscu‐ loskeletal Ultrasound has proved to be one of the most valuable imaging methods in the diagnosis of anomalies in sports medicine.

**Author details**

Massimo Manara1

2 FC Parma, Italy

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Before it gains universal acceptance in evaluation of the musculoskeletal system, however, Ultrasound must be able to produce results similar to those of MR imaging.

MR imaging is essentially the standard of care for the evaluation of the musculoskeletal system at most centres worldwide.

There exist several advantages of MR imaging over Ultrasound.

The primary advantage is relative lack of operator dependence. This is achieved through the use of standardized MR imaging protocols.

Other advantages include multiplanar capabilities, panoramic views, ability to evaluate deep muscle planes and to detect lesions missed by Ultrasound.

Another advantage is the ability of MR imaging to evaluate globally and thoroughly an anatomic area including deep soft tissues, bone marrow, and joint cartilage with high sensi‐ tivity.

Advanced technology has resulted in improved image resolution and shortened imaging times. Images may be acquired at all times of the day at various physical sites. Interpretation of images can also be accomplished promptly with data transfer to computer workstations.

Controversy exists when Ultrasound and MR imaging are compared. Unlike the research results using MR imaging, those pertaining to Ultrasound are usually more variable. Although this can be partially explained by the inherent operator dependence of this imaging method.

Additionally, there are relatively few blinded research studies that directly compare Ultra‐ sound with MR imaging. Many sonographic studies are limited to small subject groups without a gold standard. Additional research is needed to determine Ultrasound's true effectiveness in evaluating the musculoskeletal system relative to MR imaging.

Clinical studies, however, are demonstrating the potential of Ultrasound forseveral indications and interest in this imaging method continues to grow.

It is obvious that MR imaging will remain the most common advanced imaging method of the musculoskeletal system until research demonstrates that Ultrasound can produce similar results. It is clear, however, that there are several areas where musculoskeletal Ultrasound has been proved effective. Each of these points has allowed MR imaging to become widely accepted for evaluating the musculoskeletal system in sports medicine. [14]

As the images of the cases presented have shown, we too believe that MRI is to be considered the Gold Standard in muscular injuries, but we still consider Ultrasound the first choice because of its specific characteristics.

Further developments will extend applications of Ultrasound and MRI within muscularskeletal diagnostics, granting many more advantages in real-time performance, high tissue resolution and cost-benefit ratio.
