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Background: Bruxism is a common parafunctional activity that may alter the structural and mechanical properties of the masseter muscle. Shear wave elastography (SWE) provides a noninvasive and objective method for evaluating muscle stiffness. Despite increasing interest in SWE, its diagnostic value in bruxism has not been fully established. Methods: This comparative study included 2 groups: a bruxism group and a healthy control group. Bruxism was diagnosed in accordance with the diagnostic criteria for temporomandibular disorders (DC/TMD) by a dentist with 20 years of clinical experience. The control group comprised volunteers without bruxism, confirmed using the same diagnostic criteria. All participants underwent B-mode ultrasonography (US) in the supine position with their heads tilted to the opposite side at rest. US was used to assess the length and thickness of the masseter muscles, while SWE was used to measure muscle stiffness, reported in kilopascals (kPa). Results: Masseter muscle length was significantly shorter and SWE values were significantly higher in patients with bruxism compared to controls ( P < .05). A cutoff SWE value of 13.55 kPa was identified, yielding a sensitivity of 86.0% and specificity of 87.5% for the diagnosis of bruxism. The sample size in this study was larger than in previous SWE-based bruxism studies, enhancing the reliability of these findings. Conclusion: SWE demonstrates high diagnostic performance in identifying bruxism and may serve as a valuable objective tool in clinical practice. A threshold of 13.55 kPa can aid in distinguishing affected individuals with high sensitivity and specificity.

Background/Objectives: Breast abscesses and necrotic masses often show similar peripheral enhancement and a fluid-containing appearance on breast MRI, leading to diagnostic confusion. Accurate differentiation is critical because biopsies that fail to sample the lesion wall may yield false-negative results, may be misinterpreted as an infectious process, and delay diagnosis. Incorporating SWI into the protocol can provide additional clues to malignancy and, when warranted, prompt a second wall-targeted biopsy, thus reducing the risk of delayed cancer diagnosis. Methods: This single-center prospective diagnostic accuracy study included 42 female patients diagnosed between 2022 and 2025 with either necrotic breast tumors or abscesses, confirmed by histopathology. SWI-based Intralesional Susceptibility Score (ILSS), rim morphology, and mean ADC values were evaluated. Statistical analyses included the Mann–Whitney U test, chi-square test, ROC analysis, DeLong test for comparison of AUCs, and Cohen’s kappa for interobserver agreement. Results: SWI-based ILSS values were significantly higher in necrotic tumors compared to abscesses (mean ILSS: 2.28 vs. 0.85; 95% CI: 1.0–2.0; p < 0.001). Smooth hypointense rims were predominantly observed in abscesses (Sensitivity: 63.1%, 95% CI: 0.38–0.83; Specificity: 88.9%, 95% CI: 0.65–0.98; p = 0.001). Incomplete rim morphology was more frequent in tumors (Sensitivity: 78.9%, 95% CI: 0.54–0.93; Specificity: 77.8%, 95% CI: 0.52–0.93; p < 0.001). The double rim sign was highly specific for abscesses (Specificity: 95.2%, 95% CI: 0.76–0.99 p = 0.002). Conclusions: SWI provides valuable morphological information in differentiating abscesses from necrotic tumors on breast MRI. When used in combination with ADC values, it can enhance diagnostic accuracy.