Ultrasound evaluation of soft tissue masses and fluid collections.

Musculoskeletal ultrasound has utility as a first-line screening modality in the evaluation of soft tissue masses. The sonographic appearances of cysts or lipomas may be sufficient to obviate the need for further imaging. For other complex cystic or solid masses, ultrasound is an inexpensive, widely available imaging modality that can evaluate lesion vascularity, guide diagnostic and therapeutic aspiration or biopsy procedures, and be used for follow-up examinations to determine response to therapeutic interventions.