Soft-tissue sarcomas: use of textural patterns in skeletal muscle as a diagnostic feature in postoperative MR imaging.

The authors assessed the value of tissue textural patterns as a diagnostic feature for differentiating nonspecific posttreatment tissue changes from musculoskeletal sarcoma recurrence on magnetic resonance (MR) images. The MR imaging studies of 40 patients who had previously undergone surgery and radiation therapy for soft-tissue sarcomas of the lower extremities were evaluated in a blind fashion. In 31 of the MR imaging studies, T2-weighted images demonstrated diffuse areas of high signal intensity in soft tissues at the operative region. Close examination of the corresponding regions on high-resolution transverse T1-weighted images demonstrated textural features typical of skeletal muscle in 23 patients and the absence of such features in eight. None of the 23 patients with the "texture sign" proved to have macroscopic tumor recurrence at clinical or surgical follow-up. Among the eight patients without recognizable textural features of muscle in the regions suspicious for tumor recurrence, two proved to have recurrent tumor at surgery. Recognition of a texture sign on high-resolution T1-weighted spin-echo images of regions suggestive of tumor recurrence helps improve the diagnostic specificity of follow-up MR examinations in patients who have undergone treatment for soft-tissue sarcomas.