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Background In this study we sought to evaluate the contribution of dynamic four-dimensional computed tomography (4DCT) relative to the standard imaging work-up for the identification of the dorsal intercalated segment instability (DISI) in patients with suspected chronic scapholunate instability (SLI). Methods Forty patients (22 men, 18 women; mean age 46.5 ± 13.1 years) with suspected SLI were evaluated prospectively with radiographs, arthrography, and 4DCT. Based on radiographs and CT arthrography, three groups were defined: positive SLI (n = 16), negative SLI (n = 19), and questionable SLI (n = 5). Two independent readers used 4DCT to evaluate the lunocapitate angle (LCA) (mean, max, coefficient of variation [CV], and range values) during radioulnar deviation. Results The interobserver variability of the 4DCT variables was deemed excellent (intraclass correlation coefficient = 0.79 to 0.96). Between the three groups, there was no identifiable difference for the LCAmean. The LCAmax values were lower in the positive SLI group (88 degrees) than the negative SLI group (102 degrees). The positive SLI group had significantly lower LCAcv (7% vs. 12%, p = 0.02) and LCArange (18 vs. 27 degrees, p = 0.01) values than the negative SLI group. The difference in all the LCA parameters between the positive SLI group and the questionable SLI group was not statistically significant. When comparing the negative SLI and questionable SLI groups, the LCAcv (p = 0.03) and LCArange (p = 0.02) values were also significantly different. The best differentiation between patients with and without SLI was obtained with a LCAcv and LCArange threshold values of 9% (specificity of 63% and sensitivity of 62%) and 20 degrees (specificity of 71% and sensitivity of 63%), respectively. Conclusion In this study, 4DCT appeared as a quantitative and reproducible relevant tool for the evaluation of DISI deformity in cases of SLI, including for patients presenting with questionable initial radiography findings. Level of evidence This is a Level III study.

International audience; The imaging characterization of musculoskeletal tumors can be challenging, and a significant number of lesions remain indeterminate when conventional imaging protocols are used. In recent years, clinical availability of functional imaging methods has increased. Functional imaging has the potential to improve tumor detection, characterization, and follow-up. The most frequently used functional methods are perfusion imaging, diffusion-weighted imaging (DWI), and MR proton spectroscopy (MRS). Each of these techniques has specific protocol requirements and diagnostic pitfalls that need to be acknowledged to avoid misdiagnoses. Additionally, the application of functional methods in the MSK system has various technical issues that need to be addressed to ensure data quality and comparability. In this article, the application of contrast-enhanced perfusion imaging, DWI, and MRS for the evaluation of bone and soft tissue tumors is discussed, with emphasis on acquisition protocols, technical difficulties, and current clinical indications.