Ultrasound in musculoskeletal tumors with emphasis on its role in tumor follow-up.

Ultrasonography allows visualization of musculoskeletal masses that are not confined to the intraosseous compartment and assists in the determination of the consistency of such masses. Making a specific diagnosis using ultrasonography is hampered by the lack of specificity; however, it may be an indicator in guiding diagnostic needle biopsy, especially in large heterogeneous tumors. Color Doppler flow imaging allows visualization of blood flow within solid soft tissue masses. Probably, CDFI features do not assist in differentiation between malignant and benign tumors; however, it has proved to be a useful tool to monitor regression of tumor neovascularity induced by therapy in patients with musculoskeletal sarcoma. When recurrence of a soft tissue sarcoma is clinically suspected, ultrasonography can be used as the initial imaging technique for evaluation. Ultrasonography can also be used in addition to MR imaging when susceptibility artifacts secondary to orthopedic hardware (including prostheses) prevent evaluation of specific areas.