The Role of Fat Tissues in the Diagnosis of Musculoskeletal Imaging

Fat tissue is a unique component of the soft tissue, and this fat tissue lies primarily in the spaces beneath the normal subcutaneous tissue, and within or around the organs. An entire lesion, or just a part of it, can be composed of these fat tissues. Therefore, it plays an important role in the diagnostic workup of suspected musculoskeletal diseases as well as in the differentiation between them. Fat tissue is shown as low density on plain radiographs, decreased attenuation on CT images, high signal intensity on T1-weighted images and it is hypoechoic on sonography. Because of its distinctive features, fat tissue is easy to verify on various modalities.?In addition, recent image studies like fat-suppressed imaging and STIR imaging provide more precise information of the lesion that involve fat tissue. In this article, we have reviewed the differentiation of musculoskeletal diseases, including the various tumorous lesion and tumor-like lesions involving the fat tissue.

Breast Imaging Reporting and Data System (BI-RADS) US lexicon and Final Assessment Category for Solid Breast Masses: the Rates of Inter- and Intraobserver Agreement

PURPOSE: To evaluate the rates of inter- and intraobserver agreement of the BI-RADS US lexicon. MATERIALS AND METHODS: Two radiologists reviewed 60 sonograms of solid breast masses to evaluate interobserver agreement. After four weeks, the radiologists reinterpreted the series to evaluate the intraobserver agreement. The radiologists described shape, orientation, margin, lesion boundary, echo pattern, posterior acoustic features and microcalcifications. Final assessment categories and management plans were suggested for each case. The rates of inter- and intraobserver agreements were measured by the use of kappa statistics. RESULTS: Interobserver agreement ranged from the highest for orientation (k=0.65) and shape (k=0.61) to the lowest for posterior acoustic features (k=0.42). For the final assessment categories (k=0.46) and management (k=0.49), interobserver agreements were moderate. Intraobserver agreement ranged from the highest for microcalcifications in mass (k=0.90, 0.82) and orientation (k=0.87, 0.83) and the lowest for echo patterns (k=0.62, 0.57) and posterior acoustic features (k=0.59, 0.65). In the final assessment category and management, intraobserver agreements were substantial or nearly complete (k=0.65-0.83). CONCLUSION: There were variable ranged inter- and intraobserver agreements in the description of the BI-RADS US lexicon of solid breast masses. Among them, margin and lesion boundary showed lower agreements. A modification of the BI-RADS US lexicon with more detailed guidelines, followed by continuous education, are suggested.