Soft-tissue tumors--role of diagnostic imaging.

The radiologic evaluation of soft-tissue masses has changed dramatically within the last two decades. Before the introduction of computer-assisted imaging, assessment of clinically suspicious soft-tissue masses was usually limited to radiographs. Although radiographs were sensitive to the identification of adipose tissue and soft-tissue mineralization, they provided little other diagnostic information. The emergence of CT improved this situation dramatically. Masses could be not only delineated with a great confidence but well staged with excellent depiction of anatomic detail. However, diagnosis remained problematic, with images sufficiently suggesting the correct histology in only a minority of cases: typically, lipomas and hemangiomas. The introduction of MR imaging markedly improved soft-tissue contrast and multiplanar image acquisition capabilities. Depiction of anatomic detail is of high importance in the evaluation of soft-tissue tumors. Attempts were made to develop rules analogous to those for bone tumors, for differentiating benign and malignant processes on the basis of lesion morphology and signal intensity.